Weekly updates, Influenza Epidemiological Week 11 (24 March 2023)

North America: Influenza virus activity was low overall, with the predominance of influenza A viruses. The influenza A(H1N1)pdm09 virus predominated among subtyped samples, with co-circulation of A(H3N2) and B/Victoria. SARS-CoV-2 activity decreased; RSV activity was low. In Canada, all seasonal influenza subtypes circulated with low activity, influenza B virus predominated. In Mexico, influenza activity was low, with elevated SARS-CoV-2 and RSV activity. In the United States, influenza and RSV activity were low, while SARS-CoV-2 activity remained elevated. Pneumonia, influenza, and SARS-CoV-2 mortality was primarily associated with COVID-19. 

Caribbean: Influenza activity was moderate, with influenza B viruses more frequently detected. Influenza B/Victoria and A(H1N1)pdm09 co-circulated. Belize and Jamaica reported increased influenza activity. Overall, SARS-CoV-2 activity was low in the subregion, except in Dominica, where it was moderate. RSV activity was low. 

Central America: Influenza activity was moderate overall, with influenza B/Victoria virus predominance. Influenza A(H3N2) and A(H1N1)pdm09 co-circulated. Influenza activity was moderate in El Salvador, while Guatemala and Honduras reported low activity. SARS-CoV-2 percent positivity dropped in the subregion, except in Costa Rica. RSV activity was low overall. 

Andean: Influenza activity was low, predominating influenza A(H1N1)pdm09; influenza A(H3N2) and B/Victoria viruses co-circulated. Influenza activity remained elevated in Bolivia; SARI cases / 100 hospitalizations were moderate, and 14.5% tested positive for influenza. SARS-CoV-2 and RSV activity were low overall. 

Brazil and Southern Cone: Influenza activity was low; influenza B viruses were detected more frequently, with B/Victoria, A(H1N1)pdm09, and A(H3N2) co-circulation. In addition, increased SARS-CoV-2 activity was reported in Brazil, Chile, and Paraguay, while RSV was elevated in Brazil. 

Avian Influenza: A summary of the avian influenza situation in the region, case management and recommendations are available at Epidemiological alerts and updates | PAHO/WHO | Pan American Health Organization (paho.org)