Weekly updates, Influenza Epidemiological Week 45 (18 November 2022)

North America: Influenza activity is moderate in the subregion, with the predominance of influenza A(H3N2) and co-circulation of influenza A(H1N1)pdm09 and influenza B (lineage undetermined). The SARS-CoV-2 activity was low, while RSV activity remained elevated. In Canada, the influenza epidemic began. In Mexico, influenza was at moderate-intensity levels. Increased influenza and RSV activity was reported across the United States.

Caribbean: Influenza activity was moderate across the subregion with A(H3N2) virus predominance and co-circulation of influenza B (lineage undetermined). In contrast, SARS-CoV-2 activity remained low, although it appears to increase in Dominica and Haiti. In addition, increased influenza activity was reported in the Dominican Republic and Puerto Rico, while bronchiolitis remained elevated in Guadeloupe and Martinique.

Central America: Influenza activity is increasing with the predominance of influenza A(H3N2) and the co-circulation of influenza B/Victoria. SARS-CoV-2 activity remained low in the subregion, except in El Salvador, where it increased. In Guatemala and Nicaragua, influenza activity continued to increase, with influenzaassociated ILI activity increased in Guatemala. In addition, increased RSV activity was reported in El Salvador, Guatemala, and Panama.

Andean: Influenza activity remained low, with the predominance of influenza A(H3N2) and co-circulation of influenza A(H1N1)pdm09 and B/Victoria. Overall, SARS-CoV-2 and RSV activity was low in the subregion. However, Bolivia reported increased influenza activity with influenza A(H1N1)pdm09 predominance and co-circulation of B/Victoria and A(H3N2) viruses, with SARI activity increased, with 20% influenza-associated hospitalizations.

Brazil and Southern Cone: Influenza activity increased in the subregion, with influenza A(H3N2) predominance and co-circulation of influenza A(H1N1)pdm09 and influenza B/Victoria. SARS-CoV-2 activity has remained low, although Chile has shown increased activity. Argentina reported increased influenza activity with B (lineage undetermined) virus predominance. Chile reported increased influenza activity for this time of year at extraordinary-intensity levels; ILI was increased with 29% ILI cases positive for influenza, while increased SARI cases, although at low-intensity levels, 14% were positive for SARS-CoV-2 versus 6% influenza cases. RSV activity remained elevated in Brazil, but it is decreasing.