Regional Update, Influenza. Epidemiological Week 47 (2 December 2022)

ABSTRACT

[WEEKLY SUMMARY]. North America Influenza activity continues moderate in the subregion. Influenza A(H3N2) predominated with the co-circulation of A(H1N1)pdm09 and B/Victoria. Low SARS-CoV-2 activity was reported but increasing, while RSV activity was moderate overall. In Canada, influenza activity and most surveillance indicators continue to increase. Mexico experiences extraordinary influenza activity for this period, with surveillance indicators at low-intensity levels. Increased influenza and RSV activity was reported across the United States, with the influenza-associated cumulative hospitalization rate at higher levels than in previous seasons (2010-21). Caribbean Influenza activity continues moderate across the subregion with A(H3N2) virus predominance. In contrast, SARS-CoV-2 activity remained low. In addition, the Dominican Republic and Puerto Rico have shown increased influenza activity but continue at low-intensity levels, while Guadeloupe and Martinique recorded increased RSV activity. Central America Influenza activity is increasing with the predominance of influenza A(H3N2) and the co-circulation of influenza B (lineage undetermined). SARS-CoV-2 activity remained low in the subregion, but it increased in El Salvador and Panama. In addition, in Guatemala and Honduras, influenza activity increased, albeit RSV activity continues to be high in Guatemala and Panama. Andean Influenza activity has recently increased 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, except in Peru, where SARS-CoV-2 activity was high. In Bolivia, increased influenza activity was reported with influenza A(H1N1)pdm09 predominance and co-circulation of B/Victoria and A(H3N2) viruses; SARI activity increased, with 15% influenza-associated hospitalizations. Influenza activity was at moderate-intensity levels in Ecuador, with severity indicators continuing at a low level. Brazil and Southern Cone Influenza activity continues elevated in the subregion for this time of year, with influenza A(H3N2) predominance and co-circulation of influenza A(H1N1)pdm09 and influenza B/Victoria. In addition, Argentina and Paraguay reported increased influenza activity with influenza B (lineage undetermined) predominance, Chile with A(H3N2) predominance, and Uruguay with B/Victoria predominance. SARS-CoV-2 activity has increased recently, with high activity in Brazil and Chile. Elevated RSV activity was reported in Brazil, but with a decreasing trend.