Weekly update, Influenza Epidemiological Week EW 36 (september, 21)

North America: Influenza activity remained low in the subregion, with the predominance of influenza A(H3N2). SARS-CoV-2 activity continued to be elevated but decreasing. In Canada, influenza was at interseasonal levels, with decreasing SARS-CoV-2 activity. In Mexico, influenza activity increased to low-intensity levels, while SARS-CoV-2 activity declined. In the United States, influenza activity was at interseasonal levels, while SARS-CoV-2 activity was moderate, although decreasing; RSV activity continued increasing.

Caribbean: Overall, influenza activity remained low, and influenza A(H3N2) predominated. Haiti and Saint Lucia reported increased SARS-CoV-2 activity, while RSV activity continued elevated in the Dominican Republic.

Central America: Overall, influenza activity remained stable at low levels, predominating influenza A(H3N2). In Guatemala, influenza activity increased, predominating influenza A(H3N2). In El Salvador and Honduras, SARS-CoV-2 activity continued at low levels. In Nicaragua and Panama, RSV activity is increasing.

Andean Countries: Overall, influenza activity remained low, with influenza A(H3N2) predominance. SARS-CoV-2 activity continues at moderate levels in Bolivia, Ecuador, and Peru but decreasing.

Brazil and Southern Cone: Influenza activity remained low, with the detection of influenza A(H1N1)pdm09, influenza B (lineage undetermined), and the predominance of influenza A(H3N2). SARS‑CoV-2 activity was low throughout the subregion. In Brazil and Uruguay, RSV activity continues to increase.

Global: Influenza activity remained low. Overall, activity has decreased or remained low in most countries during this period. In the temperate zones of the southern hemisphere, overall influenza activity appeared to further reduce this reporting period, except in South Africa, where activity increased. In Oceania, detections of primarily influenza A(H3N2) decreased overall, and influenza-like activity (ILI) was at low levels in most Pacific Island countries. However, in Southern Africa, there was an increase in influenza activity again in recent weeks, with mainly influenza B viruses reported. In tropical Africa, influenza activity remained low, with influenza A(H3N2) viruses predominant among the reported detections. In Southern Asia, influenza detections were predominantly A(H1N1)pdm09 viruses, with influenza A(H3N2) and influenza B viruses also reported. In South-East Asia, influenza activity decreased slightly, with influenza A(H3N2) viruses predominating. In Europe, overall influenza activity remained at 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) continued to decrease in China. Elsewhere, influenza illness indicators and activity were low. In Western Asia, detections of predominantly influenza A(H3N2) and B viruses continued to be reported at low levels.

COVID-19 positivity from sentinel surveillance continued to decrease to just over 10%. The highest positivity rates were reported in the Americas, the European Region, and the Eastern Mediterranean Region, where positivity was just above 10%, while in the other regions, it remained below 5%. Conversely, the positivity rate decreased in most regions, notably in the Western Pacific Region, except in the African and European Regions, where it was stable.