Influenza Situation Report

The information presented in this update is based on data provided by Ministries of Health and National Influenza Centers of Member States to the Pan American Health Organization (PAHO) or from updates on the Member States' Ministry of Health web pages.

Weekly Summary: Epidemiological Week 20 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 decreasing trend. 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 4 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 3 EWs. 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 percent positivity. During the last 4 EW, the predominant influenza viruses have been influenza A, mostly A(H1N1)pdm09, with less circulation of influenza B /Victoria. RSV activity remained at medium levels of circulation. SARS-CoV-2 has circulated at moderate levels. SARI activity has remained high, showing a decreasing trend in the last EW with influenza accounting for over half of the cases, followed by RSV and SARS-CoV-2. ILI activity has shown a decreasing trend with most cases related to influenza.

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. RSV activity has shown an increase in the last 4 EWs. SARS-CoV-2activity has remained at low levels. After reaching high levels, SARI activity has exhibited 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 4 EW, following a period of intense activity, being the majority influenza cases.

Global: Available at Global Influenza Programme (who.int)

Avian Influenza: A summary of the avian influenza situation in the region, case management and recommendations are available at Epidemiological Alerts and Updates.