Regional Update, Influenza. Epidemiological Week 11 (29 March 2022)

ABSTRACT

[WEEKLY SUMMARY]. North America Overall, influenza activity remained at low levels and SARS-CoV-2 activity continued to decline. Canadahad reduced activity for influenza at this time of year with influenza A (subtyping not performed) predominant and co circulating with influenza/B. The percent positivity for SARS-CoV-2 was slightly higher than the previous week. In the United States, influenza activity has increased in most parts of the country although levels are still higher than in pre-pandemic seasons. Influenza A(H3N2) and B viruses co-circulated. The percentage of outpatient consultations for respiratory illness increased slightlybut is below the baseline. SARS-CoV 2 activity continues to decline, and mortality is above the epidemic threshold. In Mexico, influenza activity has decreased below the average of previous seasons’reference levels, influenza A(H3N2) predominated; the percentage of positivity for SARS CoV 2 decreased. Caribbean Influenza activity remained at low levels overall with influenza A(H3N2) predominant. In Haiti, influenza activity continued at low, but still above average activity levels. Acute respiratory consultations continue to increase in Guadeloupe, Saint-Martin and Martinique. The percent positivity for SARS-CoV-2 increased slightly at low intensity levels in the Dominican Republic, remained similar to the percentage of the previous week in Jamaica and Saint Lucia, and decreased in Belize and Haiti. Central America Overall, influenza activity remained low. In Nicaragua, the percent positivity for influenza remained unchanged at low intensity levels. SARS-CoV-2 activity decreased in Costa Rica, El Salvador, and Honduras. AndeanOverall, influenza activity decreased with a few A(H3N2) detections. Influenza positivity rate increased in Peru, decreased to baseline levels in Bolivia, and remained stable while still above average in Ecuador. SARS-CoV-2 activity decreased in Colombia, Ecuador, and Peru. Br azil and Southern Cone Overall, influenza activity continued at low levels however, an increase in the percent positivity was observed in recent weeks. The percentage of influenza positivity increased in Chile, Uruguay and Argentina, and in the latter to levels of extraordinary intensity. The activity of SARS-CoV-2 and the percent positivity increased in Brazil, but decreased in Argentina, Chile, and Uruguay. Global Influenza activity remained low and decreased during this period after a peak at the end of 2021. In the temperate zones of the northern hemisphere, influenza activity increased or remained stable with detections of mainly influenza A(H3N2) viruses and B/Victoria lineage viruses reported. In Europe, overall influenza activity appeared to rise again, with influenza A(H3N2) predominant. Very little RSV activity was observed. In East Asia, influenza activity with mainly influenza B/Victoria lineage detections increased in China. Influenza illness indicators and activity remained low in the rest of the subregion. Increased RSV activity was reported in Mongolia and the Republic of Korea. In Northern Africa, influenza detections of influenza A(H3N2) continued to be registered. In Western Asia, influenza activity was low across reporting countries. In tropical Africa, influenza activity was reported mainly from Eastern Africa with influenza A(H3N2) predominating followed by influenza B/Victoria lineage viruses, and from Middle Africa with influenza B predominantly detected. In Southern Asia, influenza virus detections were at low levels, with all subtypes detected. In South-East Asia, influenza detections were at low levels, with influenza A(H3N2) predominant. In the temperate zones of the southern hemisphere, influenza activity remained low overall. SARS-CoV-2 percent positivity from sentinel surveillance decreased across all WHO regions during this reporting period except in the South-East Asia Region where the positivity was above 40%. The positivity rate was between 10% and 30% in all Regions of WHO, with exception of the African Region where positivity remained under 10%. Overall positivity from non-sentinel sites also showed a decreasing trend.