Weekly updates, Influenza Epidemiological Week 19 (19 May 2023)

North America: Influenza activity has remained at low levels. During the last 4 EW, the predominant influenza viruses have been B/Victoria, with also circulation of influenza A (mostly A(H1N1)pdm09) at a lesser extent. Respiratory Syncytial Virus (RSV) activity has remained at low levels. SARS-CoV-2 activity has decreased however it continues circulating at high levels. SARI and ILI cases showed a decreasing trend, being most cases due to SARS-CoV-2.

Caribbean: Influenza activity has shown a rise in recent weeks with medium levels of activity; however a decreasing trend has been observed in the past 2 EWs. During the last 4 EW, the predominant influenza viruses have been B/Victoria, with less circulation of influenza A (mostly A(H1N1)pdm09). RSV activity has remained low. SARS-CoV-2 activity has shown an increase in the past 3 EWs circulating at moderate levels. SARI activity has shown a decreasing trend, with most cases related to influenza and ILI activity has remained at low levels.

Central America: Influenza activity has shown medium levels of circulation, with an increase in the last EW. During the last 4 EW, the predominant influenza viruses have been A, mostly A(H1N1)pdm09, with co-circulation on influenza A(H3N2) and influenza B /Victoria. RSV activity has remained low. SARS-CoV-2 activity has remained low and has decreased in recent weeks. SARI and ILI activity has remained low, with most cases related to SARS-CoV-2.

Andean: Influenza activity has shown an increase in the number of detections while remaining stable at low levels of positivity. During the last 4 EW, the predominant influenza viruses have been A, mostly A(H1N1)pdm09, with less circulation of influenza B (Victoria). RSV activity remained at medium levels of circulation. SARS-CoV-2 activity has circulated at moderate levels. SARI activity has remained consistently high, with influenza accounting for over half of the cases, followed by RSV and SARS-CoV-2.

Brazil and Southern Cone: Influenza activity has shown a pronounced increase with high levels of circulation.During the last 4 EW, the predominant influenza viruses have been A, mostly A(H1N1)pdm09, with co-circulation of influenza B/Victoria. After an increase in RSV activity, a decreasing trend has been observed in the past EW. SARS-CoV-2activity has remained at low levels. After reaching high levels, SARI activity hasexhibited a decline over the past four EWs, primarily attributed to cases linked to RSV and influenza. In the case of ILI, there has been a decreasing trend observed in the past three EW, following a period of intense activity, being the majority influenza cases.