Weekly updates, Influenza Epidemiological Week 1 (6 January 2023)

North America: Influenza activity was moderate and declining in the subregion, with the predominance of influenza A(H3N2) and co-circulation of A(H1N1)pdm09 and B/Victoria. The SARS-CoV-2 activity has increased, while RSV activity continued to decrease. In Canada, influenza activity has decreased; most surveillance indicators were within expected levels. In Mexico, influenza activity continued above expected levels; severity indicators were low. In the United States, influenza activity declined at low-intensity levels, with the percentage of deaths due to pneumonia, influenza, and COVID-19 above the average of previous seasons. RSV activity continued decreasing.

Caribbean: Influenza activity was moderate in the subregion with A(H3N2) virus predominance, A(H1N1)pdm09, and B/Victoria co-circulated. Influenza percent positivity increased in Belize and Haiti. SARS-CoV-2 activity remained low overall; however, Belize, Haiti, and Jamaica reported increased COVID-19 activity. In addition, RSV activity was increased in Jamaica.

Central America: Influenza activity was at moderate levels, with the predominance of influenza A(H3N2) and the co-circulation of influenza A(H1N1)pdm09 and B/Victoria (where lineage was determined). Influenza activity was elevated in Honduras, with the circulation of influenza B (lineage undetermined). SARS-CoV-2 percent positivity decreased in the subregion, with an increased percent positive in Costa Rica, Guatemala, and Honduras. In addition, Guatemala reported increased RSV activity.

Andean: Influenza activity was low but increasing, with the predominance of influenza A(H3N2) and co-circulation of influenza A(H1N1)pdm09 and B/Victoria. Influenza activity was elevated in Bolivia and Ecuador, with increased SARI activity at low-intensity levels in both countries. In addition, SARS-CoV-2 percent positivity increased in Colombia, Ecuador, and Peru. In the subregion, RSV activity was low overall, with an increasing trend.

Brazil and Southern Cone: Influenza activity decreased to low levels, with influenza A(H3N2) predominance and co-circulation of influenza A(H1N1)pdm09 and influenza B/Victoria. Argentina and Chile reported declining influenza activity. SARS-CoV-2 activity was elevated across the subregion but with a decreasing trend. Increased RSV activity continued to be reported in Brazil and Chile.