Weekly update, Influenza. Epidemiological week 30 (August 10, 2022)

North America: Overall, influenza activity decreased in the subregion while SARS-CoV-2 percent positivity increased. In Mexico, influenza activity remained low with A(H3N2) virus predominance; moderate SARI and high-intensity ILI activity were related to elevated SARS-CoV-2 circulation. In the United States, influenza activity was low, with the predominance of the influenza A(H3N2) virus. In addition, RSV activity remained stable compared to previous weeks, while SARS-CoV-2 activity and COVID-19-associated hospitalizations remained elevated.

Caribbean: Influenza activity remained low, with the influenza A(H3N2) virus predominance in the sub-region. The Dominican Republic reported increased SARS-CoV-2 activity with SARI hospitalizations below the epidemic thresholds, while in Haiti, elevated SARS-CoV-2 and SARI activity were reported. In the Dominican Republic, RSV activity remained elevated as expected at the beginning of the season with SARS-CoV-2 cocirculation.

Central America: Influenza activity continued to decrease in the subregion, with the predominance of the influenza A(H3N2) virus, while RSV activity increased. In Nicaragua, influenza activity increased to moderate-intensity levels, with the A(H3N2) virus predominance and co-circulation of RSV. SARS-CoV-2 activity rose across the subregion, with increased levels in Costa Rica, Honduras, and Guatemala. Influenza and SARS-CoV-2-associated ILI counts remained at moderate levels in Guatemala.

Andean Countries: Influenza activity remained low with A(H3N2) predominance, except in Bolivia and Peru, where circulation increased above epidemic levels.SARS-CoV-2 activity continued to increase in Bolivia, Colombia, and Peru. In Bolivia, SARI hospitalizations rose to high-intensity levels driven by influenza and SARS-CoV-2 co-circulation.

Brazil and Southern Cone: Overall, influenza activity remained at low levels with influenza A(H3N2) predominance and was driven by its circulation in Chile and Uruguay. SARS-CoV-2 activity continued   to   increase   throughout   the subregion. Chile, Paraguay, and Uruguay reported SARI activity elevated above epidemic levels for the period, with RSV and SARS-CoV-2 predominance in Chile and Uruguay. SARS-CoV-2 predominated in Paraguay.

Global: Influenza activity has steadily decreased from a peak in March 2022. In the temperate zones of the southern hemisphere, overall influenza activity appeared to decline during this reporting period. In Oceania, detections of primarily influenza A (H3N2) decreased overall, but elevated ILI activity was notified in some Pacific Islands. In Southern Africa, influenza activity decreased overall with continued detections of influenza A(H1N1)pdm09, influenza A(H3N2), and a few influenza B viruses. In tropical Africa, influenza activity continued to decrease. Influenza A viruses predominated among the reported detections. In Southern Asia, influenza detections of predominantly A(H3N2) were at similar levels to previous weeks and remained at low levels overall. In South-East Asia, influenza virus detections decreased. Influenza A(H3N2) predominated. In Europe, overall influenza activity remained at low inter-seasonal levels, with influenza A(H3N2) predominant among the subtyped viruses. In Central Asia and Northern Africa no influenza detections were reported. In East Asia, influenza activity of predominantly influenza A(H3N2) seemed to have peaked. Elsewhere, influenza illness indicators and activity remained low. In Western Asia, low numbers of detections of influenza A(H1N1)pdm09, A(H3N2), and B viruses were reported.