Regional Update, Influenza. Epidemiological Week 44 (11 November 2022)

ABSTRACT

[WEEKLY SUMMARY]. 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, influenza activity is increasing. In Mexico, influenza was at moderate-intensity levels. Increased influenza activity was reported in the United States . Caribbean Influenza activity remained low across the subregion with A(H3N2) virus predominance and co-circulation of influenza B (lineage undetermined). The SARS-CoV-2 activity was very low. Influenza activity is increasing in Jamaica and Puerto Rico. ILI activity remained elevated in Guadeloupe and Martinique. Central America Influenza activity remained low but increased 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. Guatemala and Nicaragua reported increased influenza activity with A(H3N2) predominance in the first and influenza B (lineage undetermined) in the latter. In addition, RSV activity increased in El Salvador and Guatemala. Andean Influenza activity remained low, with the predominance of influenza A(H3N2) and co-circulation of influenza A(H1N1)pdm09 and B (lineage undetermined). Overall, SARS-CoV-2 and RSV activity was low in the subregion. Bolivia reported increased influenza activity with co-circulation of A(H3N2) and A(H1N1)pdm09. 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 . Argentina reported increased influenza activity with B (lineage undetermined) virus predominance, while Chile reported increased influenza activity for this time of year at high-intensity levels; ILI was increased with 35% ILI cases positive for influenza and 2.7% for SARS-CoV-2. In addition, RSV activity increased in Brazil. Global Influenza activity increased, and where subtyped, influenza A(H3N2) viruses predominated. An increasing trend of influenza activity was observed in the northern hemisphere, while a plateau was observed in the southern hemisphere. In Europe, influenza activity followed an increasing trend but remained relatively low. Influenza A viruses predominated among the reported detections, with A(H3N2) viruses accounting for most subtyped influenza A viruses. In central Asia, Kazakhstan reported high influenza activity with B/Victoria lineage viruses predominating. In East Asia, influenza activity of predominantly influenza A(H3N2) remained stable at intermediate levels. In Western Asia, influenza activity was elevated. Influenza detections continued to increase in some countries of the Arabian Peninsula. In tropical Africa, influenza activity remained low, with detections of influenza A(H3N2), B/Victoria, and A(H1N1)pdm09 reported. In Southern Asia, influenza activity increased steeply, with elevated activity reported in Bhutan, Iran, and Pakistan. Most subtyped detections were influenza A(H3N2), followed by A(H1N1)pdm09, and a few influenza B detections. In South East Asia, detections of predominantly influenza A(H3N2) followed by influenza B and influenza A(H1N1)pdm09 decreased. In the temperate zones of the southern hemisphere, influenza activity appeared to decrease during this reporting period. In Oceania, influenza activity remained very low, with detections of influenza A(H1N1)pdm09 and influenza A(H3N2) and some B viruses in Australia. In Southern Africa, decreasing detections of influenza B/Victoria and influenza A(H3N2) were reported. SARS-CoV-2 positivity from sentinel surveillance increased slightly but remained under 10% after a long-term downtrend beginning in mid-2022. Activity rose sharply in the Region of the Americas, with percent positivity reaching 20%. In the European Region, positivity was stable at around 10%. The Western Pacific Region's positivity declined sharply but remained just above 10%. Positivity declined and was below 10% in all other regions. COVID-19 positivity from non-sentinel surveillance increased to over 10% due to increased positivity in South-East Asia and Western Pacific Regions.