Regional Update, Influenza and Other Respiratory Viruses. Epidemiological Week 34 (30 August 2024)

Regional Update, Influenza and Other Respiratory Viruses. Epidemiological Week 34 (30 August 2024)

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Regional Update, Influenza and Other Respiratory Viruses. Epidemiological Week 34 (30 August 2024). (2024). [Newsletters]. PAHO. https://iris.paho.org/handle/10665.2/61591

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InfluRep30ago2024.pdf (11.06 MB)

English and Spanish; 75 pages

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2024-08-30

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Pan American Health Organization

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[WEEKLY SUMMARY]. Regional Situation: During the last four epidemiological weeks (EW), there has been a decrease in the activity of Influenza- Like Illness (ILI). Activity has been observed in the Southern Cone, the Caribbean, and Central America. This activity is linked to the circulation of RSV in the Southern Cone and Central America, influenza in the Caribbean, and SARS-CoV-2 in North America, the Caribbean, and Central America. Additionally, epidemic levels of Severe Acute Respiratory Infection (SARI) have been observed in the Southern Cone, the Andean subregion, and Central America, related to positive cases of RSV, and to a lesser extent, influenza. In North America, there has been an increase in activity related to the circulation of SARS-CoV-2. Regarding the circulation of respiratory viruses at the regional level, SARS-CoV-2 activity has increased, particularly in North America, the Caribbean, and the Andean subregion. Additionally, although influenza activity has decreased, it remains fluctuating in some Caribbean countries and the Andean subregion. RSV activity has reached epidemic levels in Central America, the Andean subregion, and the Southern Cone. North America: Cases of ILI, SARI, and hospitalizations associated with respiratory viruses, after showing an increase in recent weeks, have begun to decline, although the majority of positive cases are attributable to SARS-CoV-2. Influenza activity has remained below the epidemic threshold in all countries. During this period, the predominant influenza viruses have been A(H3N2), followed by A(H1N1)pdm09 and B/Victoria. RSV activity has remained low. In contrast, SARS-CoV-2 activity has remained at levels similar to the peaks observed in the previous 2023-2024 wave. By country: • In Canada, SARS-CoV-2 activity has increased, reaching levels close to the peaks recorded in previous waves. Influenza activity remains below the epidemic threshold, while RSV activity remains low. • In Mexico, after rising to moderate levels in previous epidemiological weeks, ILI and SARI cases have shown a marked decline in the last four weeks. Most positive cases are attributable to SARS-CoV-2, which is currently declining. Both influenza and RSV activity remain low. • In the United States, the hospitalization rate associated with SARS-CoV-2 per 100,000 inhabitants has shown a decline in the last three weeks, and SARS-CoV-2 positivity rates have reached values similar to the peaks observed in 2023 and 2024. Influenza and RSV activity continue to remain low. Caribbean: Following the rise observed in previous weeks, ILI cases have shown a decreasing trend over the past four EW, associated with a higher proportion of positive influenza cases. SARI cases have remained low. Influenza activity has fluctuated, though declining at moderate levels over the past four EW, with A(H3N2) being predominant, followed by A(H1N1)pdm09. RSV activity has remained low, though showing a slight increase, and SARS-CoV-2 activity remains high. By country: In the last four EW, influenza activity has been observed in Belize, the Dominican Republic, and Guyana. Additionally, SARSCoV- 2 activity has been recorded in Belize, Jamaica, Barbados, Guyana, the Cayman Islands, and Saint Vincent and the Grenadines. • In Guyana, following an increase in ILI and SARI activity in previous weeks, a decline has been observed in the last two EW, with positive cases attributable to influenza, and to a lesser extent, SARS-CoV-2. Central America: After the increase in ILI and SARI activity observed in previous weeks, there has been a decline in the last three EW, with most positive cases attributable to SARS-CoV-2 and RSV, whose activity has shown an upward trend. Influenza activity, after reaching epidemic levels in several countries in the subregion, has declined over the past four EW. During this period, the predominant influenza viruses have been A(H3N2). RSV activity continues to rise, reaching levels similar to the peaks recorded in previous seasons. After reaching levels similar to the peaks observed in previous waves, SARS-CoV-2 activity has shown a downward trend over the past four EW. By country: • In Costa Rica, following the increase in ILI and SARI cases in previous weeks, a decreasing trend has been observed over the past four EW, with most positive cases attributable to SARS-CoV-2, whose activity is declining, and to a lesser extent, influenza, which is currently declining below the epidemic threshold. RSV activity has shown a slight increase, although it remains low. • In El Salvador, after reaching moderate levels, influenza circulation has shown a decline over the past four EW, falling below the epidemic threshold. SARS-CoV-2 has shown an increase, although it remains low compared to previous waves. • In Guatemala, there has been an increase in ILI activity to moderate levels, with most positive cases attributable to SARSCoV- 2, and to a lesser extent, influenza and RSV. SARI activity has increased to epidemic levels, with a significant rise in the proportion of positive RSV cases. • In Honduras, over the past four EW, SARI activity has fluctuated at epidemic levels, mainly associated with positive influenza cases, which are currently at epidemic levels, and to a lesser extent, SARS-CoV-2 and RSV. • In Nicaragua, after influenza circulation exceeded the elevated threshold, it has declined over the past four EW to levels below the epidemic threshold, and SARS-CoV-2 circulation remains low. However, RSV positivity rates have risen to levels similar to the peaks observed in previous seasons. • In Panama, ILI and SARI cases, following the increase observed in previous weeks, have experienced a slight decline over the past four EW. Most positive cases are attributable to RSV, whose activity has shown a significant increase, and to a lesser extent, SARS-CoV-2, whose activity remains low. Additionally, influenza activity has remained below the epidemic threshold. Andean: ILI and SARI activity has shown a decline over the past four EW in most countries. Additionally, there has been an increase in the proportion of positive SARS-CoV-2 cases, with a decrease in the proportion of positive RSV and influenza cases, whose activity has continued to decline during this period. The predominant influenza viruses have been A(H3N2). RSV activity has remained stable at moderate levels, while SARS-CoV-2 activity has remained at moderate levels compared to previous waves. By country: • In Bolivia, SARI cases are fluctuating around the epidemic threshold. Influenza activity has decreased to levels below this threshold. SARS-CoV-2 and RSV activity remain low. • In Colombia, SARI activity, after reaching epidemic levels in recent weeks, has declined below this threshold. Most positive cases are attributed to RSV, whose activity is declining, and to a lesser extent, SARS-CoV-2, which shows circulation levels similar to the peaks observed in previous waves. Acute Respiratory Infection (ARI) cases have decreased to epidemic levels. • In Ecuador, SARI and pneumonia activity has remained at epidemic levels over the past four EW. Positive SARI cases are mainly attributed to influenza, which is at epidemic levels, and to a lesser extent, RSV and SARS-CoV-2, which is on the rise. • In Peru, an increase in SARS-CoV-2 activity has been observed, although at levels lower than in previous waves. RSV has shown a decrease, and influenza activity remains below the epidemic threshold. • In Venezuela, there has been an increase in influenza activity, rising above the epidemic threshold, and a slight increase in RSV activity, which remains at low levels. Brazil and the Southern Cone: Following the increase observed in previous weeks, SARI activity has shown a decline over the past four EW, with most positive cases attributable to RSV. ILI activity has shown a slight uptick, associated with an increase in the proportion of positive SARS-CoV-2 cases. Influenza activity is declining, remaining below the epidemic threshold in most countries. During this period, the predominant influenza viruses have been A(H1N1)pdm09 and A(H3N2). RSV activity has shown a slight decrease after reaching levels below the peaks observed in previous seasons. SARS-CoV-2 activity has remained low, although showing a slight increase. By country: • In Argentina, ILI activity, after reaching high levels, has declined to levels below the epidemic threshold, while SARI activity, after reaching epidemic levels, has also fallen below this threshold. Influenza activity, after reaching high levels, has declined to epidemic levels. Meanwhile, RSV, after reaching positivity levels similar to the peaks observed in previous seasons, has shown a declining trend, and SARS-CoV-2, although at low levels, has shown a slight increase. • In Brazil, ILI and SARI activity has declined to levels below the epidemic threshold. Influenza activity is also decreasing below the epidemic threshold, while RSV activity remains low. However, SARS-CoV-2 activity has shown a slight increase, though it remains low. • In Chile, after the decline observed in previous weeks, there has been a rebound in ILI and SARI cases, with extraordinary and moderate levels, respectively. Most positive cases during the past four EW are attributable to RSV, whose activity remains elevated, although with positivity levels below the peaks observed in previous seasons. Influenza activity, after reaching extraordinary levels, has declined below the epidemic threshold. • In Paraguay, SARI activity remains at moderate levels, with most positive cases attributable to RSV, whose activity is declining, and to a lesser extent SARS-CoV-2, which is increasing. ILI activity, after reaching epidemic levels, has declined below this threshold, though showing a slight increase in the last week. • In Uruguay, SARI activity has shown a slight decline to epidemic levels, with most positive cases attributable to RSV, whose activity has reached positivity levels higher than the peaks observed in previous seasons.

[RESUMEN SEMANAL]. Situación regional: Durante las últimas cuatro semanas epidemiológicas (SE), se ha registrado un descenso en la actividad de Enfermedad Tipo Influenza (ETI). Se ha observado actividad en el Cono Sur, el Caribe y Centroamérica. Esta actividad está vinculada con la circulación de VRS en el Cono Sur y Centroamérica, influenza en el Caribe, así como del SARS-CoV-2 en Norteamérica, el Caribe y Centroamérica. Además, se han observado niveles epidémicos de Infección Respiratoria Aguda Grave (IRAG) en el Cono Sur, la subregión Andina y Centroamérica, relacionados con casos positivos de VRS, y en menor medida, de influenza. En Norteamérica, se ha detectado un incremento en la actividad relacionado con la circulación del SARS-CoV-2. En cuanto a la circulación de virus respiratorios a nivel regional, se ha observado un aumento en la actividad del SARS-CoV-2, especialmente en Norteamérica, el Caribe y la subregión Andina. Asimismo, aunque la actividad de influenza ha disminuido, se mantiene fluctuante en algunos países del Caribe y de la subregión Andina. La actividad del Virus Respiratorio Sincitial (VRS) ha alcanzado niveles epidémicos en América Central, la subregión Andina y el Cono Sur. América del Norte: Los casos de ETI, IRAG y las hospitalizaciones asociadas a virus respiratorios, tras haber mostrado un incremento en semanas previas, han comenzado a descender, aunque la mayor proporción de casos positivos son atribuibles a SARS-CoV-2. La actividad de la influenza se ha mantenido por debajo del umbral epidémico en todos los países. Durante este periodo, los virus de influenza predominantes han sido del tipo A(H3N2), seguidos por A(H1N1)pdm09 y B/Victoria. La actividad del VRS ha permanecido en niveles bajos. En contraste, la actividad del SARS-CoV-2 se ha mantenido en niveles similares a los máximos observados en la ola previa 2023-2024. Por países: • En Canadá, la actividad del SARS-CoV-2 ha incrementado, alcanzando niveles cercanos a los máximos registrados en olas previas. La actividad de la influenza sigue por debajo del umbral epidémico, mientras que la actividad del VRS se mantiene en niveles bajos. • En México, después de un ascenso hasta niveles moderados en semanas epidemiológicas previas, los casos de ETI e IRAG han mostrado un marcado descenso en las cuatro últimas SE. La mayoría de los casos positivos son atribuibles a SARSCoV- 2 que se encuentra en descenso. Tanto la actividad de la influenza como la del VRS se mantienen en niveles bajos. • En Estados Unidos, la tasa de hospitalizaciones asociadas a SARS-CoV-2 por cada 100,000 habitantes ha mostrado un descenso en las tres últimas semanas y los niveles de positividad para SARS-CoV-2 han alcanzado valores similares a los picos observados en 2023 y 2024. La actividad de la influenza y la del VRS continúan en niveles bajos. Caribe: Tras el ascenso observado es semanas previas, en las últimas cuatro SE, los casos de ETI han mostrado una tendencia decreciente, asociados a una mayor proporción de casos positivos de influenza. Los casos de IRAG han permanecido en niveles bajos. La actividad de influenza se ha mantenido fluctuante aunque en descenso en niveles intermedios durante las últimas cuatro SE, con predominio del tipo A(H3N2) y, en menor medida, de influenza A(H1N1)pdm09. La actividad del VRS se ha mantenido en niveles bajos, aunque mostrando un ligero incremento, y la actividad del SARS-CoV-2 sigue en niveles elevados. Por países: En las últimas cuatro SE, se ha observado actividad de influenza en Belice, República Dominicana y Guyana. Asimismo, se ha registrado actividad de SARS-CoV-2 en Belice, Jamaica, Barbados, Guyana, las Islas Caimán y San Vicente y las Granadinas. • En Guyana, tras el aumento en la actividad de ETI e IRAG en semanas previas, se ha observado un descenso en las dos últimas SE, con casos positivos atribuibles a influenza, y en menor medida SARS-CoV-2. América Central: tras el incremento observado en la actividad de ETI e IRAG en semanas previas, se ha producido un descanso en las tres últimas SE, con la mayoría de los casos positivos atribuibles a SARS-CoV-2 y VRS, cuya actividad ha mostrado un ascenso. La actividad de influenza, tras alcanzar niveles epidémicos en varios países de la subregión, ha mostrado un descenso en las últimas cuatro SE. Durante este periodo, los virus de influenza predominantes han sido de tipo A(H3N2). La actividad del VRS se mantiene en ascenso, alcanzando niveles similares a los máximos registrados en temporadas previas. La actividad del SARS-CoV-2 tras alcanzar niveles similares a los máximos observados en olas anteriores, ha presentado una tendencia decreciente en las cuatro últimas SE. Por países: • En Costa Rica, tras el aumento detectado en los casos de ETI e IRAG en semanas previas, durante las cuatro últimas SE se ha observado una tendencia decreciente, con la mayoría de los casos positivos atribuibles a SARS-CoV-2, cuya actividad se encuentra en descenso, y en menor medida a influenza, que actualmente se encuentra en descenso por debajo del umbral epidémico. La actividad del VRS ha mostrado un ligero ascenso, aunque manteniéndose en niveles bajos. • En El Salvador, la circulación de influenza, tras alcanzar niveles moderados, ha presentado un descenso en las últimas cuatro SE hasta situarse por debajo del umbral epidémico. El SARS-CoV-2 ha mostrado un ascenso, aunque se mantiene en niveles bajos en comparación con olas previas. • En Guatemala, se ha observado un incremento en la actividad de ETI hasta niveles moderados, con la mayoría de los casos positivos atribuibles a SARS-CoV-2 y en menor medida influenza y VRS. La actividad de IRAG ha presentado un incremento situándose en niveles epidémicos; con un marcado incremento en la proporción de casos positivos a VRS. • En Honduras, en las últimas cuatro SE, la actividad de IRAG se ha mantenido fluctuante entre niveles epidémicos, asociada principalmente a casos positivos de influenza, que actualmente se encuentra en niveles epidémicos, y en menor medida a SARS-CoV-2 y VRS. • En Nicaragua, tras alcanzar niveles de circulación de influenza por encima del umbral elevado, durante las cuatro últimas SE se ha observado un descenso hasta niveles por debajo del umbral epidémico y la circulación del SARS-CoV-2 se mantiene en niveles bajos. Sin embargo, los niveles de positividad del VRS han ascendido hasta niveles máximos observados en temporadas previas. • En Panamá, los casos de ETI e IRAG tras el incremento observado en semanas previas, ha experimentado un ligero descenso en las cuatro últimas SE. La mayoría de los casos positivos son atribuibles a VRS, cuya actividad ha mostrado un marcado ascenso, y en menor medida a SARS-CoV-2 cuya actividad permanece baja. Asimismo, la actividad de influenza se ha mantenido por debajo del umbral epidémico. Andina: La actividad de ETI e IRAG ha mostrado un descenso en las últimas cuatro SE en la mayoría de los países. Asimismo, se ha observado un aumento en la proporción de casos positivos de SARS-CoV-2, con un descenso en la proporción de casos positivos de VRS e influenza, cuya actividad ha permanecido en descenso durante este periodo. Los virus de influenza predominantes han sido de tipo A(H3N2). La actividad del VRS se ha mantenido estable en niveles moderados, mientras que la actividad de SARS-CoV-2 se ha mantenido en niveles medios en comparación con olas previas. Por países: • En Bolivia, los casos de IRAG se encuentran fluctuantes en torno al umbral epidémico. La actividad de influenza ha disminuido hasta niveles inferiores a este umbral. La actividad de SARS-CoV-2 y VRS se mantienen bajas. • En Colombia, la actividad de IRAG, tras alcanzar niveles epidémicos en las últimas semanas, ha presentado un descenso por debajo de este umbral. La mayoría de los casos positivos se atribuyen a VRS, cuya actividad se encuentra en descenso, y en menor medida a SARS-CoV-2, que muestra niveles de circulación similares a los máximos observados en olas anteriores. Los casos de IRA (Infección Respiratoria Aguda) han descendido a niveles epidémicos. • En Ecuador, la actividad de IRAG y neumonía se ha mantenido en niveles epidémicos en las últimas cuatro SE. Los casos positivos de IRAG se atribuyen principalmente a influenza, cuya actividad se encuentra en niveles epidémicos, y en menor medida a VRS y SARS-CoV-2, que se encuentra en ascenso. • En Perú, se ha observado un incremento en la actividad de SARS-CoV-2 aunque con niveles inferiores a olas previas. El VRS ha mostrado un descanso y la actividad de influenza se mantiene por debajo del umbral epidémico. • En Venezuela, se ha observado un incremento en la actividad de influenza, situándose por encima del umbral epidémico y un ligero incremento en la actividad de VRS que se mantiene en niveles bajos. Brasil y el Cono Sur: Tras el incremento observado en semanas previas, la actividad de IRAG ha mostrado un descenso en las últimas cuatro SE, con la mayoría de los casos positivos atribuibles a VRS. La actividad de ETI ha mostrado un ligero repunte, asociado con un incremento en la proporción de casos positivos a SARS-CoV-2. La actividad de influenza se encuentra en descenso, situándose por debajo del umbral epidémico en la mayoría de los países. Durante este periodo, los virus de influenza predominantes han sido de tipo A(H1N1)pdm09 y A(H3N2). La actividad del VRS ha mostrado un ligero descenso, tras alcanzar niveles inferiores a los máximos observados en temporadas previas. La actividad del SARS-CoV-2 se ha mantenido en niveles bajos, aunque mostrando un ligero incremento. Por países: • En Argentina, la actividad de ETI, tras alcanzar niveles elevados, ha descendido a niveles por debajo del umbral epidémico, mientras que la actividad de IRAG, tras alcanzar niveles epidémicos, también ha caído por debajo de este umbral. La actividad de influenza, después de alcanzar niveles elevados, ha descendido a niveles epidémicos. Paralelamente, el VRS tras alcanzar valores de positividad similares a los máximos observados en temporadas previas ha mostrado una tendencia decreciente y el SARS-CoV-2 aunque en niveles bajos ha mostrado un ligero incremento. • En Brasil, la actividad de ETI e IRAG ha descendido a niveles por debajo del umbral epidémico. La actividad de influenza se encuentra en descenso, también por debajo del umbral epidémico, y la actividad de VRS se mantiene en niveles bajos, mientras que la actividad del SARS-CoV-2 ha mostrado un ligero incremento, aunque se mantiene en niveles bajos. • En Chile, tras el descenso observado en semanas previas, se ha registrado un repunte en los casos de ETI e IRAG, con niveles extraordinarios y moderados, respectivamente. La mayoría de los casos positivos durante las últimas cuatro SE son atribuibles a VRS, cuya actividad se mantiene elevada, aunque con niveles de positividad por debajo de los máximos observados en temporadas anteriores. La actividad de influenza, tras alcanzar niveles extraordinarios, ha descendido a niveles por debajo del umbral epidémico. • En Paraguay, la actividad de IRAG se mantiene en niveles moderados, con la mayoría de los casos positivos atribuibles a VRS, cuya actividad está en descenso, y en menor medida, a SARS-CoV-2, cuya actividad está en ascenso. La actividad de ETI, tras alcanzar niveles epidémicos, ha descendido por debajo de este umbral, aunque mostrando un ligero ascenso en la última semana. • En Uruguay, la actividad de IRAG ha presentado un ligero descenso hasta niveles epidémicos, con la mayoría de los casos positivos atribuibles a VRS, cuya actividad ha alcanzado niveles de positividad superiores a los picos observados en temporadas anteriores.

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Regional Update, Influenza and Other Respiratory Viruses. Epidemiological Week 37 (20 September 2024)
(PAHO, 2024-09-20) Organización Panamericana de la Salud
[WEEKLY SUMMARY]. Regional Situation: Influenza-Like Illness (ILI) and Severe Acute Respiratory Infection (SARI) activity have shown an overall decreasing trend in recent epidemiological weeks (EWs). In North America and the Caribbean, most cases have been associated with SARS-CoV-2 and, to a lesser extent, influenza, both of which are declining. In Central America, the Andean region, and the Southern Cone, cases have decreased, with most positive results linked to RSV, SARS-CoV-2, and influenza. SARS-CoV-2 activity remains elevated in North America, though it has begun to decrease in most countries, as well as in some areas of the Caribbean and the Andean subregion, where the declining trend continues. In contrast, a slight increase has been observed in Brazil and the Southern Cone. Influenza has shown a general decline, although it continues to fluctuate in certain Caribbean and Andean countries. Meanwhile, RSV activity has started to decline in the Andean subregion and the Southern Cone, following epidemic levels in previous weeks, but remains high in some Central American countries. North America: Cases of ILI, SARI, and hospitalizations associated with respiratory viruses, after showing an increase in previous weeks, have started to decrease. The majority of positive cases are attributable to SARS-CoV-2, although this proportion is also decreasing. Influenza activity has remained below the epidemic threshold in all countries. During this period, the predominant influenza viruses have been A(H3N2), followed by A(H1N1)pdm09 and B/Victoria. RSV activity has remained low. In contrast, SARS-CoV-2 activity has remained at levels similar to the peaks observed in the previous 2023-2024 wave. By country: • In Canada, SARS-CoV-2 activity remains on the rise, reaching levels close to the peaks recorded in previous waves. Influenza activity remains below the epidemic threshold, while RSV activity remains low. • In Mexico, after rising to moderate levels in previous epidemiological weeks, ILI and SARI cases have shown a marked decline over the last four weeks to epidemic levels. Most positive cases are attributable to SARS-CoV-2, which is currently declining. Both influenza and RSV activity remain low. • In the United States, the hospitalization rate associated with SARS-CoV-2 per 100,000 inhabitants has declined over the last four weeks. SARS-CoV-2 positivity levels, after reaching values similar to the peaks observed in 2023 and 2024, have shown a decreasing trend over the last four EW. Influenza and RSV activity continue to remain low. Caribbean: ILI cases have maintained a declining trend, associated with a higher proportion of positive influenza cases. SARI cases have remained low, with most positive cases associated with SARS-CoV-2. Influenza activity has been declining over the past four EW, with A(H3N2) being predominant, followed by A(H1N1)pdm09. RSV activity has remained low, while SARS-CoV- 2 activity remains high compared to previous waves, although declining. By country: In the last four EW, influenza activity has been observed in Belize, the Dominican Republic, Saint Lucia, Suriname, and Guyana. Additionally, SARS-CoV-2 activity has been recorded in Haiti, Jamaica, Saint Lucia, Barbados, Guyana, and Saint Vincent and the Grenadines. RSV activity has also been detected in the Dominican Republic and Guyana. • In Jamaica, there has been an increase in SARI cases, which remain below the epidemic threshold, as well as pneumonia cases at moderate levels. This coincides with the peak in SARS-CoV-2 positivity detected in previous weeks, which is now declining. • In Guyana, after an increase in ILI and SARI activity in previous weeks, a decline has been observed in the most recent EW, with positive cases attributable to influenza, and to a lesser extent, SARS-CoV-2 and RSV. • In Saint Lucia, an increase in SARI activity has been detected, fluctuating around the epidemic threshold over the past four EW, coinciding with the circulation of SARS-CoV-2 and, to a lesser extent, influenza. Central America: A decline in ILI and SARI activity has been observed over the past four EW, with most positive ILI cases attributable to SARS-CoV-2, which is declining, and most positive SARI cases attributable to RSV, which is increasing. Influenza activity, after reaching epidemic levels in several countries of the subregion, has declined over the past four EW. During this period, the predominant influenza viruses have been B/Victoria, followed by A(H3N2). RSV activity remains on the rise, reaching levels similar to the peaks recorded in previous seasons. After reaching levels similar to the peaks observed in previous waves, SARS-CoV-2 activity has shown a downward trend over the past four EW to low levels. By country: • In Costa Rica, following the increase in ILI and SARI cases in previous weeks, a decreasing trend has been observed over the past four EW to epidemic levels. Most positive ILI cases are attributable to SARS-CoV-2, and most positive SARI cases are attributable to RSV. SARSCoV- 2 activity, after reaching peak levels seen in previous waves, has declined. RSV activity has shown a slight increase, although it remains low compared to previous seasons. Influenza activity remains below the epidemic threshold. • In El Salvador, after reaching moderate levels, influenza circulation has shown a decline over the past four EW, falling below the epidemic threshold. After a slight increase, SARS-CoV-2 activity remains low compared to previous waves. RSV activity remains low. • In Guatemala, there has been a slight increase in ILI activity to epidemic levels, with most positive cases attributable to influenza, and to a lesser extent, SARS-CoV-2 and RSV. SARI activity has also increased to epidemic levels, with a significant rise in the proportion of positive RSV cases. • In Honduras, over the past four EW, SARI activity has fluctuated at epidemic levels, mainly associated with positive influenza cases, which are currently fluctuating at epidemic levels, and to a lesser extent, SARS-CoV-2 and RSV, both of which are declining to low levels. • In Nicaragua, influenza levels have been below the epidemic threshold over the last four EW, and SARS-CoV-2 circulation remains low. However, RSV positivity rates have risen to levels similar to the peaks observed in previous seasons and continue to rise. • In Panama, ILI and SARI cases, after the increase observed in previous weeks, have shown a slight decline over the past four EW. Most positive cases are attributable to RSV, whose activity, after a significant increase to levels similar to those observed in previous seasons, has begun to decline. Additionally, fewer positive cases of SARS-CoV-2 have been detected, with activity remaining low. Influenza activity has remained below the epidemic threshold. Andean: ILI and SARI activity has shown a decline over the past four EW in most countries. Influenza activity has remained low and declining, with the predominant viruses being B/Victoria, followed by A(H3N2). RSV activity has been decreasing at moderate levels, and SARS-CoV-2 activity is declining after reaching moderate levels compared to previous waves. By country: • In Bolivia, SARI cases are below the epidemic threshold. Influenza activity has decreased to levels below this threshold. SARS-CoV-2 and RSV activity remain low, with a slight increase in SARS-CoV-2 activity. • In Colombia, ILI and SARI activity have declined below the epidemic threshold over the past four EW. Most positive cases are attributed to RSV, whose activity is declining, and to a lesser extent, SARS-CoV-2, which, after reaching circulation levels similar to the peaks observed in previous waves, has declined to low levels. Acute Respiratory Infection (ARI) cases have decreased to epidemic levels. • In Ecuador, SARI and pneumonia activity have shown a decline, reaching levels around the epidemic threshold. Positive SARI cases are mainly attributed to influenza, whose activity is fluctuating at epidemic levels, and to a lesser extent, SARS-CoV-2, which, after increased activity in previous weeks, is now declining. • In Peru, after the increase in SARS-CoV-2 activity observed in previous weeks, a decline has been detected, with levels lower than in previous waves. RSV activity has decreased, and influenza activity remains below the epidemic threshold. • In Venezuela, a decline in influenza activity has been observed, and RSV activity remains low. Brazil and the Southern Cone: Following the increase observed in previous weeks, SARI activity has shown a decline over the past four EW, with most positive cases attributable to RSV, whose activity is also decreasing. ILI activity, after showing an uptick associated with an increase in the proportion of positive SARS-CoV-2 cases, has now recorded a decline over the last two EW. Influenza activity remains below the epidemic threshold in most countries. During this period, the predominant influenza viruses have been B/Victoria, followed by A(H1N1)pdm09 and, to a lesser extent, A(H3N2). By country: • In Argentina, ILI activity, after reaching high levels, has declined to levels below the epidemic threshold. Meanwhile, SARI activity, after reaching epidemic levels, has also fallen below this threshold. Influenza activity remains at epidemic levels, showing a slight uptick over the last two EW. RSV, after reaching positivity levels similar to the peaks observed in previous seasons, has shown a declining trend, while SARS-CoV-2, although at low levels, has shown a slight increase. • In Brazil, influenza activity remains below the epidemic threshold, and RSV activity remains low. Additionally, SARS-CoV-2 activity has shown a slight increase, although it remains low compared to previous waves. • In Chile, after the uptick in ILI and SARI cases, a decline has been recorded to moderate and epidemic levels, respectively. Most positive SARI cases are attributable to RSV, whose activity remains elevated, although with positivity levels below the peaks observed in previous seasons. Positive ILI cases are attributable to both RSV and influenza, whose activity, while remaining below the epidemic threshold, has shown a slight increase in recent weeks. SARS-CoV-2 activity remains low. • In Paraguay, SARI activity remains at moderate levels, with most positive cases attributable to RSV, whose activity is declining, and to a lesser extent, SARS-CoV-2, whose activity is increasing. ILI activity has shown a slight uptick associated with SARS-CoV-2, RSV, and influenza, but remains below the epidemic threshold. Influenza activity has shown a slight uptick over the last two EW, reaching levels around the epidemic threshold. • In Uruguay, ILI and SARI activity have shown a progressive decline to epidemic levels, with most positive cases attributable to RSV, whose positivity levels have exceeded the peaks observed in previous seasons and are now declining. Influenza and SARS-CoV-2 activity remain low.
Regional Update, Influenza and Other Respiratory Viruses. Epidemiological Week 36 (13 September 2024)
(PAHO, 2024-09-13) Pan American Health Organization
[WEEKLY SUMMARY]. Regional Situation: During the last four epidemiological weeks (EW), there has been a decrease in Influenza-Like Illness (ILI) activity, with cases reported in the Southern Cone, the Caribbean, and Central America. Additionally, epidemic levels of Severe Acute Respiratory Infection (SARI) have been reported in the Southern Cone, the Andean subregion, and Central America, mainly associated with the circulation of RSV and SARS-CoV-2. Regarding the circulation of respiratory viruses at the regional level, elevated SARS-CoV-2 activity has been observed, particularly in North America, the Caribbean, and the Andean subregion, with a declining trend in the latter two. Although influenza activity has decreased, it remains fluctuating in some Caribbean countries and the Andean subregion. Meanwhile, RSV activity has reached epidemic levels in Central America, the Andean subregion, and the Southern Cone. North America: Cases of ILI, SARI, and hospitalizations associated with respiratory viruses, after showing an increase in previous weeks, have begun to decline. The majority of positive cases are attributable to SARS-CoV-2, although this proportion is also decreasing. Influenza activity has remained below the epidemic threshold in all countries. During this period, the predominant influenza viruses have been A(H3N2), followed by A(H1N1)pdm09 and B/Victoria. RSV activity has remained low. In contrast, SARS-CoV-2 activity has remained at levels similar to the peaks observed in the 2023-2024 wave. By country: • In Canada, SARS-CoV-2 activity remains on the rise, reaching levels close to the peaks recorded in previous waves. Influenza activity remains below the epidemic threshold, while RSV activity remains low. • In Mexico, after rising to moderate levels in previous epidemiological weeks, ILI and SARI cases have shown a marked decline over the last four weeks to epidemic levels. Most positive cases are attributable to SARS-CoV-2, which is currently declining. Both influenza and RSV activity remain low. • In the United States, the hospitalization rate associated with SARS-CoV-2 per 100,000 inhabitants has declined over the last four weeks. SARS-CoV-2 positivity levels, after reaching values similar to the peaks observed in 2023 and 2024, have shown a decreasing trend over the last four EW. Influenza and RSV activity continue to remain low. Caribbean: ILI cases have maintained a declining trend, associated with a higher proportion of positive influenza cases. SARI cases have remained low, with the majority of positive cases attributed to SARS-CoV-2. Influenza activity has been declining over the past four EW, with A(H3N2) being predominant, followed by A(H1N1)pdm09. RSV activity has remained low, and SARS-CoV-2 activity remains high, though declining. By country: In the last four EW, influenza activity has been observed in Belize, the Dominican Republic, Saint Lucia, Suriname, and Guyana. Additionally, SARS-CoV-2 activity has been recorded in Belize, Haiti, Jamaica, Saint Lucia, Barbados, Guyana, and Saint Vincent and the Grenadines. RSV activity has been detected in the Dominican Republic and Guyana. • In Jamaica, there has been an increase in SARI cases, which remain below the epidemic threshold, as well as pneumonia cases at moderate levels. This coincides with the peak in SARS-CoV-2 positivity detected in previous weeks, which is now declining. • In Guyana, after an increase in ILI and SARI activity in previous weeks, a decline has been observed in the most recent EW, with positive cases attributable to influenza, and to a lesser extent, SARS-CoV-2 and RSV. • In Saint Lucia, an increase in SARI activity has been detected, surpassing the epidemic threshold in the last EW, coinciding with the circulation of SARS-CoV-2 and, to a lesser extent, influenza. • In Barbados, after the increase in SARI cases detected in recent EW alongside heightened SARS-CoV-2 activity, a decline has been observed, coinciding with decreased SARS-CoV-2 positivity over the last four EW. Central America: After the increase in ILI and SARI activity observed in previous weeks, a decline has been recorded over the past four EW, with most positive ILI cases attributed to SARS-CoV-2, which is decreasing, and most SARI cases attributed to RSV, which is increasing. Influenza activity, after reaching epidemic levels in several countries of the subregion, has declined over the past four EW. During this period, the predominant influenza viruses have been B/Victoria, followed by A(H3N2). RSV activity continues to rise, reaching levels similar to the peaks recorded in previous seasons. After reaching levels similar to the peaks observed in previous waves, SARS-CoV-2 activity has shown a downward trend over the past four EW to low levels. By country: • In Costa Rica, following the increase in ILI and SARI cases in previous weeks, a decreasing trend has been observed over the past four EW to epidemic levels, with most positive ILI cases attributed to SARS-CoV-2 and most positive SARI cases attributed to RSV. SARS-CoV-2 activity, after reaching peak levels observed in previous waves, has declined. RSV activity has shown a slight increase, although it remains low compared to previous seasons. Influenza activity remains below the epidemic threshold. • In El Salvador, after reaching moderate levels, influenza circulation has shown a decline over the past four EW, falling below the epidemic threshold. After a slight increase, SARS-CoV-2 activity remains low compared to previous waves. RSV activity remains low. • In Guatemala, there has been an increase in ILI activity to epidemic levels, with most positive cases attributed to influenza, and to a lesser extent, SARS-CoV-2 and RSV. SARI activity has also increased to epidemic levels, with a significant rise in the proportion of positive RSV cases. • In Honduras, over the past four EW, SARI activity has fluctuated at epidemic levels, mainly associated with positive influenza cases, which are currently fluctuating at epidemic levels, and to a lesser extent, SARS-CoV-2 and RSV, which are both declining to low levels. • In Nicaragua, after influenza circulation exceeded the elevated threshold, levels have fallen below the epidemic threshold over the past four EW, and SARS-CoV-2 circulation remains low. However, RSV positivity rates have risen to levels similar to the peaks observed in previous seasons and continue to rise. • In Panama, ILI and SARI cases, after the increase observed in previous weeks, have shown a slight decline over the past four EW. Most positive cases are attributable to RSV, whose activity, after a significant increase to levels similar to those observed in previous seasons, has begun to decline. Additionally, there have been fewer positive cases of SARS-CoV-2, whose activity remains low. Influenza activity has remained below the epidemic threshold. Andean: ILI and SARI activity has shown a decline over the past four EW in most countries. Influenza activity has remained low and declining, with the predominant viruses being B/Victoria, followed by A(H3N2). RSV activity has been decreasing at moderate levels, and SARS-CoV-2 activity is declining after reaching moderate levels compared to previous waves. By country: • In Bolivia, SARI cases are below the epidemic threshold. Influenza activity has decreased to levels below this threshold. SARS-CoV-2 and RSV activity remain low, with a slight increase in SARS-CoV-2 activity. • In Colombia, ILI and SARI activity have declined below the epidemic threshold over the past four EW. Most positive cases are attributed to RSV, whose activity is declining, and to a lesser extent, SARS-CoV-2, which, after reaching circulation levels similar to the peaks observed in previous waves, has shown a decline. Acute Respiratory Infection (ARI) cases have decreased to epidemic levels. • In Ecuador, SARI and pneumonia activity have shown a decline to levels below the epidemic threshold. Positive SARI cases are mainly attributed to influenza, whose activity is fluctuating at epidemic levels, and to a lesser extent, RSV and SARSCoV- 2, which, after increased activity in previous weeks, are now declining. • In Peru, after an increase in SARS-CoV-2 activity in previous weeks, a decline has been detected, with levels lower than in previous waves. RSV activity has decreased, and influenza activity remains below the epidemic threshold. • In Venezuela, a decline in influenza activity has been observed, and RSV activity remains low. Brazil and the Southern Cone: Following the increase observed in previous weeks, SARI activity has shown a decline over the past four EW, with most positive cases attributed to RSV, whose activity is also decreasing. ILI activity has shown an uptick, associated with an increase in the proportion of positive SARS-CoV-2 cases, whose activity is rising. Influenza activity remains below the epidemic threshold in most countries. During this period, the predominant influenza viruses have been B/Victoria, followed by A(H1N1)pdm09, and to a lesser extent, A(H3N2). By country: • In Argentina, ILI activity, after reaching high levels, has declined to levels below the epidemic threshold, while SARI activity, after reaching epidemic levels, has also fallen below this threshold. Influenza activity, after reaching high levels, has declined to epidemic levels. Meanwhile, RSV, after reaching positivity levels similar to the peaks observed in previous seasons, has shown a declining trend, while SARS-CoV-2, although at low levels, has shown a slight increase. • In Brazil, influenza activity remains below the epidemic threshold, and RSV activity remains low. Additionally, SARS-CoV-2 activity has shown a slight increase, though it remains low compared to previous waves. • In Chile, after the uptick in ILI and SARI cases, with extraordinary and epidemic levels, respectively, a decline has been observed. Most positive cases are attributable to RSV, whose activity remains elevated, although with positivity levels below the peaks observed in previous seasons. Influenza activity, after reaching extraordinary levels, has declined below the epidemic threshold. SARS-CoV-2 activity remains low. • In Paraguay, SARI activity remains at moderate levels, with most positive cases attributable to RSV, whose activity is declining, and to a lesser extent, SARS-CoV-2, whose activity is increasing. ILI activity has shown a slight uptick associated with SARS-CoV-2 and RSV but remains below the epidemic threshold. • In Uruguay, ILI and SARI activity have declined to epidemic levels, with most positive cases attributable to RSV, whose activity has reached positivity levels higher than the peaks observed in previous seasons and is now declining. Influenza and SARS-CoV-2 activity remain low.
Regional Update, Influenza and Other Respiratory Viruses. Epidemiological Week 35 (6 September 2024)
(PAHO, 2024-09-06) Pan American Health Organization
[WEEKLY SUMMARY]. Regional Situation: During the last four epidemiological weeks (EW), there has been a decrease in Influenza-Like Illness (ILI) activity, with cases reported in the Southern Cone, the Caribbean, and Central America. Additionally, epidemic levels of Severe Acute Respiratory Infection (SARI) have been reported in the Southern Cone, the Andean subregion, and Central America, mainly associated with the circulation of RSV and SARS-CoV-2. Regarding the circulation of respiratory viruses at the regional level, elevated SARS-CoV-2 activity has been observed, particularly in North America, the Caribbean, and the Andean subregion, with a declining trend in the latter two regions. Although influenza activity has decreased, it remains fluctuating in some Caribbean countries and the Andean subregion. Meanwhile, RSV activity has reached epidemic levels in Central America, the Andean subregion, and the Southern Cone. North America: Cases of ILI, SARI, and hospitalizations associated with respiratory viruses, after showing an increase in previous weeks, have begun to decline. The majority of positive cases are attributable to SARS-CoV-2, although this proportion is also decreasing. Influenza activity has remained below the epidemic threshold in all countries. During this period, the predominant influenza viruses have been A(H3N2), followed by A(H1N1)pdm09 and B/Victoria. RSV activity has remained low. In contrast, SARS-CoV-2 activity has remained at levels similar to the peaks observed in the 2023-2024 wave. By country: • In Canada, SARS-CoV-2 activity has increased, reaching levels close to the peaks recorded in previous waves. Influenza activity remains below the epidemic threshold, while RSV activity remains low. • In Mexico, after rising to moderate levels in previous epidemiological weeks, ILI and SARI cases have shown a marked decline in the last four weeks. Most positive cases are attributable to SARS-CoV-2, which is currently declining. Both influenza and RSV activity remain low. • In the United States, the hospitalization rate associated with SARS-CoV-2 per 100,000 inhabitants has shown a decline over the last three weeks, and SARS-CoV-2 positivity rates have reached values similar to the peaks observed in 2023 and 2024. Influenza and RSV activity continue to remain low. Caribbean: Following the rise observed in previous weeks, ILI cases have shown a declining trend over the past four EW, associated with a higher proportion of positive influenza cases. SARI cases have remained low, though with an increasing proportion of positive SARS-CoV-2 cases. Influenza activity has been declining over the past four EW, with A(H3N2) being predominant, followed by A(H1N1)pdm09. RSV activity has remained low, while SARS-CoV-2 activity remains high. By country: In the last four EW, influenza activity has been observed in Belize, the Dominican Republic, and Guyana. Additionally, SARSCoV- 2 activity has been recorded in Belize, Haiti, Jamaica, Barbados, Guyana, and Saint Vincent and the Grenadines. • In Guyana, following an increase in ILI and SARI activity in previous weeks, a decline has been observed in the last two EW, with positive cases attributable to influenza, and to a lesser extent, SARS-CoV-2. Central America: After the increase in ILI and SARI activity observed in previous weeks, there has been a decline over the past three EW, with most positive cases attributable to SARS-CoV-2, which is decreasing, and RSV, which is increasing. Influenza activity, after reaching epidemic levels in several countries in the subregion, has declined over the past four EW. During this period, the predominant influenza viruses have been B/Victoria, followed by A(H3N2). RSV activity continues to rise, reaching levels similar to the peaks recorded in previous seasons. After reaching levels similar to the peaks observed in previous waves, SARS-CoV-2 activity has shown a downward trend over the past four EW. By country: • In Costa Rica, following the increase in ILI and SARI cases in previous weeks, a declining trend has been observed over the past four EW. Most positive ILI cases are attributable to SARS-CoV-2, while most positive SARI cases are attributable to RSV. SARS-CoV-2 activity, after reaching peak levels seen in previous waves, has declined. RSV activity has shown a slight increase, although it remains low. Influenza activity remains below the epidemic threshold. • In El Salvador, after reaching moderate levels, influenza circulation has shown a decline over the past four EW, falling below the epidemic threshold. After a slight increase, SARS-CoV-2 activity remains low compared to previous waves. • In Guatemala, there has been an increase in ILI activity to moderate levels, with most positive cases attributable to SARS-CoV-2, and to a lesser extent, influenza and RSV. SARI activity has also increased to epidemic levels, with a significant rise in the proportion of positive RSV cases. • In Honduras, over the past four EW, SARI activity has fluctuated at epidemic levels, mainly associated with positive influenza cases, which are currently fluctuating at epidemic levels, and to a lesser extent, SARS-CoV-2 and RSV. • In Nicaragua, after influenza circulation exceeded the elevated threshold, levels have fallen below the epidemic threshold over the past four EW, and SARS-CoV-2 circulation remains low. However, RSV positivity rates have risen to the peaks observed in previous seasons. • In Panama, ILI and SARI cases, after the increase observed in previous weeks, have experienced a slight decline over the past four EW. Most positive cases are attributable to RSV, whose activity has shown a significant increase, reaching levels similar to those observed in previous seasons. To a lesser extent, positive cases are attributable to SARS-CoV-2, whose activity remains low. Additionally, influenza activity has remained below the epidemic threshold. Andean: ILI and SARI activity has shown a decline over the past four EW in most countries. Influenza activity has remained low, with the predominant viruses being B/Victoria, followed by A(H3N2). RSV activity has remained stable at moderate levels, while SARS-CoV-2 activity is declining after reaching moderate levels compared to previous waves. By country: • In Bolivia, SARI cases are below the epidemic threshold. Influenza activity has decreased to levels below this threshold. SARS-CoV-2 and RSV activity remain low, with a slight increase in SARS-CoV-2. • In Colombia, ILI and SARI activity has declined below the epidemic threshold over the past four EW. Most positive cases are attributed to RSV, whose activity is declining, and to a lesser extent, SARS-CoV-2, which, after reaching circulation levels similar to the peaks observed in previous waves, has shown a decline. Acute Respiratory Infection (ARI) cases have decreased to epidemic levels. • In Ecuador, SARI and pneumonia activity has remained at epidemic levels over the past four EW. Positive SARI cases are mainly attributed to influenza, which is at epidemic levels, and to a lesser extent, RSV and SARS-CoV-2, which is increasing. • In Peru, after the increase in SARS-CoV-2 activity observed in previous weeks, a decline has been detected, with levels lower than in previous waves. RSV activity has decreased, and influenza activity remains below the epidemic threshold. • In Venezuela, a decline in influenza activity has been observed, and RSV activity remains low. Brazil and the Southern Cone: Following the increase observed in previous weeks, SARI activity has shown a decline over the past four EW, with most positive cases attributable to RSV. ILI activity has shown an uptick, associated with an increase in the proportion of positive SARS-CoV-2 cases. Influenza activity is declining, remaining below the epidemic threshold in most countries. During this period, the predominant influenza viruses have been B/Victoria, followed by A(H1N1)pdm09 and A(H3N2). RSV activity has shown a decline after reaching levels below the peaks observed in previous seasons. SARS-CoV-2 activity continues to increase, although still at low levels compared to previous waves. By country: • In Argentina, ILI activity, after reaching high levels, has declined to levels below the epidemic threshold, while SARI activity, after reaching epidemic levels, has also fallen below this threshold. Influenza activity, after reaching high levels, has declined to epidemic levels. Meanwhile, RSV, after reaching positivity levels similar to the peaks observed in previous seasons, has shown a declining trend, while SARS-CoV-2, although at low levels, has shown a slight increase. • In Brazil, ILI and SARI activity have declined to levels below the epidemic threshold. Influenza activity is also decreasing below the epidemic threshold, while RSV activity remains low. However, SARS-CoV-2 activity has shown a slight increase, although it remains low compared to previous waves. • In Chile, after the uptick observed in ILI and SARI cases, with extraordinary and epidemic levels, respectively, a slight decline has been observed. Most positive cases are attributable to RSV, whose activity remains elevated, although with positivity levels below the peaks observed in previous seasons. Influenza activity, after reaching extraordinary levels, has declined below the epidemic threshold. SARSCoV- 2 activity remains low. • In Paraguay, SARI activity remains at moderate levels, with most positive cases attributable to RSV, whose activity is declining, and to a lesser extent, SARS-CoV-2, whose activity is increasing. ILI activity has shown a slight uptick associated with SARS-CoV-2 and RSV but remains below the epidemic threshold. • In Uruguay, ILI and SARI activity have declined to epidemic levels, with most positive cases attributable to RSV, whose activity has reached positivity levels higher than the peaks observed in previous seasons. Influenza and SARS-CoV-2 activity have remained low.
Regional Update, Influenza and Other Respiratory Viruses. Epidemiological Week 33 (23 August 2024)
(PAHO, 2024-08-23) Pan American Health Organization
[WEEKLY SUMMARY]. Regional Situation: During the last four epidemiological weeks (EW), there has been epidemic activity of Influenza-Like Illness (ILI) in the Southern Cone, along with increased activity in the subregions of North America, the Caribbean, and Central America. This activity is linked to the circulation of RSV in the Southern Cone and Central America, influenza in the Caribbean, as well as SARS-CoV-2 in North America, the Caribbean, and Central America. Additionally, epidemic levels of Severe Acute Respiratory Infection (SARI) have been observed in the Southern Cone, the Andean subregion, and Central America, related to positive cases of RSV, and to a lesser extent, influenza. In North America, there has been an uptick in activity related to the circulation of SARS-CoV-2. Regarding the circulation of respiratory viruses at the regional level, SARS-CoV-2 activity has increased, particularly in North America, the Caribbean, Central America, and the Andean subregion. Additionally, although influenza activity has decreased, it remains fluctuating in some Caribbean countries and the Andean subregion. RSV activity has reached epidemic levels in Central America, the Andean subregion, and the Southern Cone, and has shown an increase in the Caribbean. North America: Cases of ILI, SARI, and hospitalizations associated with respiratory viruses, after showing an increase in recent weeks, have begun to decline, although the majority of positive cases are attributable to SARS-CoV-2. Influenza activity has remained below the epidemic threshold in all countries. During this period, the predominant influenza viruses have been A(H3N2), followed by A(H1N1)pdm09 and B/Victoria. RSV activity has remained low. In contrast, SARS-CoV-2 activity has remained at levels similar to the peaks observed in the previous 2023-2024 wave. By country: • In Canada, SARS-CoV-2 activity has increased, reaching levels close to the peaks recorded in previous waves. Influenza activity remains below the epidemic threshold, while RSV activity remains low. • In Mexico, after rising to moderate levels in previous epidemiological weeks, ILI and SARI cases have shown a marked decline in the last four weeks. Most positive cases are attributable to SARS-CoV-2. Both influenza and RSV activity remain low. • In the United States, the hospitalization rate associated with SARS-CoV-2 per 100,000 inhabitants has increased over the last four weeks, and SARS-CoV-2 positivity rates have reached values similar to the peaks observed in 2023 and 2024. Influenza and RSV activity continue to remain low. Caribbean: Following the rise observed in previous weeks, ILI cases have shown a decreasing trend over the past four EW, associated with a higher proportion of positive influenza cases. SARI cases have remained low. Influenza activity has fluctuated, though declining at moderate levels over the past four EW, with A(H3N2) being predominant, followed by A(H1N1)pdm09. RSV activity has remained low, though showing a slight increase, and SARS-CoV-2 activity remains high. By country: In the last four EW, influenza activity has been observed in Belize, the Dominican Republic, and Guyana. Additionally, SARSCoV- 2 activity has been recorded in Belize, Jamaica, Saint Lucia, Barbados, Guyana, the Cayman Islands, and Saint Vincent and the Grenadines. RSV activity has also been observed in Suriname. • In Saint Lucia, an increase in SARI activity has been observed, reaching epidemic levels associated with SARS-CoV-2 circulation. • In Guyana, following an increase in ILI and SARI activity in previous weeks, a decline has been observed in the last two EW, with positive cases attributable to influenza, and to a lesser extent, SARS-CoV-2. Central America: After the increase in ILI and SARI activity observed in previous weeks, a decline has occurred in the last two EW, with most positive cases attributable to SARS-CoV-2 and RSV, whose activity has shown an upward trend. Influenza activity, after reaching epidemic levels in several countries in the subregion, has declined over the past four EW. During this period, the predominant influenza viruses have been A(H3N2). RSV activity continues to rise, reaching levels similar to the peaks recorded in previous seasons. After reaching levels similar to the peaks observed in previous waves, SARS-CoV-2 activity has shown a downward trend over the past four EW. By country: • In Costa Rica, following the increase in ILI and SARI cases in previous weeks, a decreasing trend has been observed over the past four EW, with most positive cases attributable to SARS-CoV-2, whose activity is declining, and to a lesser extent, influenza, which is currently declining below the epidemic threshold. RSV activity has shown a slight increase, although it remains low. • In El Salvador, after reaching moderate levels, influenza circulation has shown a decline over the past four EW, falling below the epidemic threshold. SARS-CoV-2 is on the rise, although it remains low compared to previous waves. • In Guatemala, there has been an increase in ILI activity to moderate levels, with most positive cases attributable to SARS-CoV-2, and to a lesser extent, influenza and RSV. SARI activity has increased to epidemic levels, with a significant rise in the proportion of positive RSV cases. • In Honduras, over the past four EW, SARI activity has fluctuated at epidemic levels, mainly associated with positive influenza cases, which is currently at epidemic levels, and to a lesser extent, SARS-CoV-2 and RSV. • In Nicaragua, after influenza circulation exceeded the elevated threshold, it has declined over the past four EW to levels below the epidemic threshold, and SARS-CoV-2 circulation remains low. However, RSV positivity rates have risen to levels similar to the peaks observed in previous seasons. • In Panama, ILI and SARI cases, following the increase observed in previous weeks, have experienced a slight decline over the past four EW. Most positive cases are attributable to RSV, whose activity has shown a significant increase, and to a lesser extent, SARS-CoV-2, whose activity remains low. Additionally, influenza activity has remained below the epidemic threshold. Andean: ILI and SARI activity has shown a decline over the past four EW in most countries. Additionally, there has been an increase in the proportion of positive SARS-CoV-2 cases, with a decrease in the proportion of positive RSV and influenza cases, whose activity has continued to decline during this period. The predominant influenza viruses have been A(H3N2). RSV activity has remained stable at moderate levels, while SARS-CoV-2 activity has shown a sharp increase to moderate levels compared to previous waves. By country: • In Bolivia, SARI cases are fluctuating around the epidemic threshold. Influenza activity has decreased to levels below this threshold. SARS-CoV-2 and RSV activity remain low. • In Colombia, SARI activity, after reaching epidemic levels in recent weeks, has declined below this threshold. Most positive cases are attributed to RSV, whose activity is declining, and to a lesser extent, SARS-CoV-2, which is on the rise, with circulation levels similar to the peaks observed in previous waves. Acute Respiratory Infection (ARI) cases have decreased to epidemic levels. • In Ecuador, SARI and pneumonia activity has remained around the moderate threshold in the past four EW. Positive SARI cases are mainly attributed to influenza, which is at epidemic levels, and to a lesser extent, RSV and SARS-CoV-2. • In Peru, an increase in RSV and SARS-CoV-2 activity has been observed, although both remain below levels seen in previous seasons and waves, respectively. Influenza activity remains below the epidemic threshold. • In Venezuela, there has been an increase in influenza activity, rising above the epidemic threshold, and a slight increase in RSV activity, which remains at low levels. Brazil and the Southern Cone: Following the increase observed in previous weeks, SARI activity has declined over the past four EW, with most positive cases attributable to RSV and, to a lesser extent, influenza. ILI activity has shown a slight uptick, associated with an increase in the proportion of positive RSV and SARS-CoV-2 cases. Influenza activity is declining, remaining below the epidemic threshold in most countries. During this period, the predominant influenza viruses have been A(H1N1)pdm09 and A(H3N2). RSV activity has shown a slight decrease after reaching levels below the peaks observed in previous seasons. SARS-CoV-2 activity has remained low, although showing a slight increase. By country: • In Argentina, ILI activity, after reaching high levels, has declined to levels below the epidemic threshold, while SARI activity, after reaching epidemic levels, has also fallen below this threshold. Influenza activity, after reaching high levels, has declined to epidemic levels. Meanwhile, RSV, after reaching positivity levels similar to the peaks observed in previous seasons, has shown a declining trend, and SARS-CoV-2, although at low levels, has shown a slight increase. • In Brazil, ILI and SARI activity has declined to levels below the epidemic threshold. Influenza activity is also decreasing below the epidemic threshold, while RSV activity remains low. However, SARS-CoV-2 activity has shown a slight increase, though it remains low. • In Chile, after the decline observed in previous weeks, there has been a rebound in ILI and SARI cases, with extraordinary and epidemic levels, respectively. Most positive cases during the past four EW are attributable to RSV, whose activity remains on the rise, although with positivity levels below the peaks observed in previous seasons. Influenza activity, after reaching extraordinary levels, has declined below the epidemic threshold. • In Paraguay, SARI activity remains at moderate levels, with most positive cases attributable to RSV, whose activity is declining, and to a lesser extent SARS-CoV-2, which is increasing. ILI activity, after reaching epidemic levels, has declined below this threshold. • In Uruguay, SARI activity has shown a slight decline to epidemic levels, with mos
Regional Update, Influenza and Other Respiratory Viruses. Epidemiological Week 32 (16 August 2024)
(PAHO, 2024-08-16) Pan American Health Organization
[WEEKLY SUMMARY]. Regional Situation: During the last four epidemiological weeks (EW), there has been epidemic activity of Influenza-Like Illness (ILI) in the Southern Cone, along with increased activity in the subregions of North America, the Caribbean, and Central America. This activity is linked to the circulation of RSV in the Southern Cone and Central America, influenza in the Caribbean, as well as SARS-CoV-2 in North America, the Caribbean, and Central America. Additionally, epidemic levels of Severe Acute Respiratory Infection (SARI) have been observed in the Southern Cone, the Andean subregion, and Central America, related to positive cases of RSV, and to a lesser extent, influenza. In North America, there has been an uptick in activity related to the circulation of SARS-CoV-2. Regarding the circulation of respiratory viruses at the regional level, SARS-CoV-2 activity has increased, particularly in North America, the Caribbean, Central America, and the Andean subregion. Additionally, although influenza activity has decreased, it remains fluctuating in some Caribbean countries and the Andean subregion. RSV activity has reached epidemic levels in Central America, the Andean subregion, and the Southern Cone, and has shown an increase in the Caribbean. North America: After a rise in cases of ILI, SARI, and hospitalizations associated with respiratory viruses in recent weeks, there has been a gradual decline, although there has been a significant increase in the proportion of positive SARS-CoV-2 cases. Influenza activity has remained below the epidemic threshold in all countries. During this period, the predominant influenza viruses have been A(H3N2), followed by A(H1N1)pdm09 and B/Victoria. RSV activity has stayed low. In contrast, SARS-CoV-2 activity has shown an increase, reaching levels similar to those observed in the previous 2023-2024 wave. By country: • In Canada, SARS-CoV-2 activity has risen, reaching levels close to the peaks recorded in previous waves. Influenza activity remains below the epidemic threshold, while RSV activity remains low. • In Mexico, after reaching moderate levels in previous epidemiological weeks, ILI and SARI cases have shown a marked decline in the last two weeks. Most positive cases are attributable to SARS-CoV-2. Both influenza and RSV activity remain low. • In the United States, the SARS-CoV-2 hospitalization rate per 100,000 inhabitants has increased in recent weeks, reaching levels similar to the peaks observed in 2023 and 2024. Influenza and RSV activity continue to remain low. Caribbean: After the rise observed in previous weeks, ILI cases have shown a declining trend over the past four EW, associated with a higher proportion of positive influenza cases. SARI cases have remained at low levels. Influenza activity has fluctuated at moderate levels during the past four EW, with A(H3N2) being predominant, followed by A(H1N1)pdm09. RSV activity has remained low, though showing a slight increase, and SARS-CoV-2 activity remains stable at high levels. By country: In the last four EW, influenza activity has been observed in Belize, the Dominican Republic, Jamaica, the Cayman Islands, and Guyana. Additionally, SARS-CoV-2 activity has been recorded in Belize, Jamaica, Saint Lucia, Barbados, Guyana, the Cayman Islands, and Saint Vincent and the Grenadines. • In Saint Lucia, an increase in SARI activity has been observed, with moderate levels linked to SARS-CoV-2 circulation, although this activity has decreased in the most recent EW. • In Guyana, there has been an increase in ILI and SARI cases, with positive cases attributable to both SARS-CoV-2 and influenza, and to a lesser extent, RSV. Central America: There has been an increase in ILI and SARI activity, with most positive cases attributable to SARS-CoV-2 and RSV, whose activity has been on the rise. Influenza activity, after reaching epidemic levels in several countries in the subregion, has declined over the past four EW. During this period, the predominant influenza viruses have been A(H3N2). RSV activity has reached levels comparable to the peaks recorded in previous seasons. SARS-CoV-2 activity is increasing, reaching levels similar to the peaks observed in previous waves. By country: • In Costa Rica, following the increase in ILI and SARI cases in previous weeks, a decreasing trend has been observed over the past four EW, with most positive cases attributable to SARS-CoV-2, whose activity is increasing, RSV, also increasing, and to a lesser extent, influenza, which is currently declining below the epidemic threshold. • In El Salvador, influenza circulation, after reaching moderate levels, has declined over the past four EW, falling below the epidemic threshold. SARS-CoV-2 is on the rise, although it remains at low levels compared to previous waves. • In Guatemala, there has been a marked increase in ILI activity to moderate levels, with most positive cases attributable to SARS-CoV-2, and to a lesser extent, RSV and influenza. SARI activity has increased to epidemic levels, with a significant increase in the proportion of positive RSV cases. • In Honduras, over the past four EW, SARI activity has fluctuated at epidemic levels, mainly associated with positive influenza cases, which is currently declining within epidemic levels, and to a lesser extent, SARS-CoV-2. • In Nicaragua, after influenza circulation exceeded the elevated threshold, it has declined over the past four EW to epidemic levels, while RSV and SARS-CoV-2 circulation remains low. • In Panama, ILI and SARI cases have increased over the past four EW, with a rise in the proportion of positive RSV cases, whose activity has shown a significant increase, alongside SARS-CoV-2. Influenza activity has declined below the epidemic threshold. Andean: ILI and SARI activity has shown a decline over the past four EW in most countries. Additionally, there has been an increase in the proportion of positive SARS-CoV-2 cases, with a decrease in the proportion of positive RSV and influenza cases, whose activity has continued to decline during this period. The predominant influenza viruses have been A(H3N2). RSV activity has remained stable at moderate levels, while SARS-CoV-2 activity has shown a sharp increase to moderate levels compared to previous waves. By country: • In Bolivia, SARI cases are fluctuating around the epidemic threshold. Influenza activity has decreased to levels below this threshold. SARS-CoV-2 and RSV activity remains low. • In Colombia, SARI activity, after reaching epidemic levels in recent weeks, has declined below this threshold. Most positive cases are attributed to RSV, whose activity is declining, and to a lesser extent, SARS-CoV-2, which is on the rise, with circulation levels similar to the peaks observed in previous waves. Acute Respiratory Infection (ARI) cases have decreased to moderate levels. • In Ecuador, SARI and pneumonia activity has remained around the moderate threshold in the past four EW. Positive SARI cases are mainly attributed to influenza, which is at epidemic levels, and to a lesser extent, RSV and SARS-CoV-2. • In Peru, after reaching extraordinary levels of SARI, there has been a decline in the past week. Most positive cases are attributable to RSV, whose activity is on the rise, and to a lesser extent, influenza, which is below the epidemic threshold. Additionally, increasing SARS-CoV-2 activity has been recorded; however, it remains at low levels. • In Venezuela, there has been an increase in influenza activity, rising above the epidemic threshold, and a slight increase in RSV activity, which remains at low levels. Brazil and the Southern Cone: Following the increase observed in previous weeks, SARI activity has declined over the past four EW, with most positive cases attributable to RSV and, to a lesser extent, influenza. ILI activity has shown a slight uptick, associated with an increase in the proportion of positive SARS-CoV-2 cases. Influenza activity is declining, remaining below the epidemic threshold in most countries. During this period, the predominant influenza viruses have been A(H1N1)pdm09 and A(H3N2). RSV activity has shown a slight decrease after reaching levels below the peaks observed in previous seasons. SARS-CoV-2 activity has remained low, although showing a slight increase. By country: • In Argentina, ILI activity, after reaching high levels, has declined to levels below the epidemic threshold, while SARI activity, after reaching epidemic levels, has also fallen below this threshold. Influenza activity, after reaching high levels, has declined to epidemic levels. Meanwhile, RSV, after reaching positivity levels similar to the peaks observed in previous seasons, has shown a downward trend, and SARS-CoV-2, although at low levels, has shown a slight increase. • In Brazil, ILI and SARI activity has declined to levels below the epidemic threshold. Influenza activity is also decreasing below the epidemic threshold, while RSV activity remains low. However, SARS-CoV-2 activity has shown a slight increase, though it remains at low levels. • In Chile, after the decline observed in previous weeks, there has been a rebound in ILI and SARI cases, with extraordinary and epidemic levels, respectively. Most positive cases during the past four EW are attributable to RSV, whose activity remains on the rise, although with positivity levels below the peaks observed in previous seasons. Influenza activity, after reaching extraordinary levels, has declined below the epidemic threshold. • In Paraguay, SARI activity remains at moderate levels, with most positive cases attributable to RSV, whose activity is declining, and to a lesser extent SARS-CoV-2, which is increasing. ILI activity, after reaching epidemic levels, has declined below this threshold. • In Uruguay, SARI activity has shown a slight decline to epidemic levels, with most positive cases attributable to RSV, whose activity continues to rise, reaching positivity levels higher than the peaks observed in previous seasons.