Regional Update, Influenza. Epidemiological Week 18 (18 May 2022)

ABSTRACT

[WEEKLY SUMMARY]. North America Overall, influenza and SARS-CoV-2 activity remained at low levels. In Canada, influenza activity increased above the average of previous seasons for this period at low intensity levels, and SARS-CoV-2 activity decreased and remained at low levels. In Mexico, influenza activity increased above the epidemic threshold and was at the average of previous seasons, and SARS-CoV-2 activity decreased. In the United States, influenza activity varied within regions and continued to increase in some states with influenza A(H3N2) viruses predominating. Caribbean Influenza activity remained at low levels, with predominating influenza A(H3N2), and overall, SARS-CoV-2 activity declined in most countries. In Belize and Dominica, influenza and SARS-CoV-2 activity and percent positivity increased. Central America Overall, influenza activity remained low and SARS-CoV-2 activity decreased in most countries. In El Salvador, influenza activity remained above-average levels at low-intensity levels. In Costa Rica and Panama, SARS-CoV-2 activity and percent positivity increased compared to previous seasons. Andean Overall, influenza activity remained low with A(H3N2) predominance. SARS-CoV-2 activity continued to decline in most countries, except in Peru, where the influenza activity with the predominance of A(H3N2) continued elevated above the average seasonal levels. In Ecuador, RSV activity continued elevated. Brazil and Southern Cone Overall, influenza with the predominance of A(H3N2) and SARS-CoV-2 activity decreased. In Brazil, SARS-CoV-2 activity increased slightly compared to the previous week. In Chile and Uruguay, influenza A(H3N2) activity and SARS-CoV-2 positivity increased slightly at low intensity levels. RSV activity continued elevated in Chile and Uruguay. Global Influenza activity continued to decrease, following a peak in March 2022. In the temperate zones of the northern hemisphere, influenza activity decreased or remained stable. Detections were mainly influenza A(H3N2) viruses and B/Victoria lineage viruses, with some detections of A(H1N1)pdm09 viruses. In Central Asia, a single influenza B detection was reported in Kazakhstan. In East Asia, influenza activity with mainly influenza B/Victoria lineage. Overall, in Europe, influenza continues to decline, with influenza A(H3N2) predominant. Very little RSV activity was observed. Detections continued to decrease in China while A(H3N2) became the predominantly detected virus across the southern provinces in China. Elsewhere, influenza illness indicators and activity remained low. In Northern Africa, Tunisia continued to report few detections of mainly influenza A(H3N2) and one influenza A(H1N1)pdm09 detection, while Egypt reported increasing detections of influenza B followed by A(H3N2). In Western Asia, influenza activity was low across reporting countries, except Georgia, where detections of influenza A(H3N2) continued to be reported although decreasing. In Southern Asia, influenza virus detections were at low levels, with a few detections of A(H3N2) and A(H1N1)pdm09 viruses. In South-East Asia, low A(H3N2) detections were reported in Singapore and Timor-Leste. In the temperate zones of the southern hemisphere, influenza activity was low overall, as expected at this time of year. Overall, COVID positivity from sentinel surveillance increased and was just above 10% during the reporting period. Activity from non-sentinel sites was varied.