Weekly updates, Influenza Epidemiological Week 13 (7 April 2023)

North America: Influenza virus activity was low in the sub-region, with the predominance of influenza B viruses and all seasonal influenza subtypes detected. SARS-CoV-2 activity was at moderate levels, with low RSV activity. Canada and the United States reported low influenza activity, while Mexico recorded increased influenza activity, although, at a low-intensity level; SARS-CoV-2 and RSV activity were increased. 

Caribbean: Influenza percent positivity was moderate, driven by influenza B/Victoria lineage viruses; influenza A(H1N1)pdm09 virus co-circulated. In Belize, influenza activity was increased, with influenza B/Victoria lineage and influenza A(H3N2) co-circulation, at low-intensity levels. SARS-CoV-2 and RSV activity were low in the subregion. 

Central America: Influenza activity was moderate, with influenza A and B viruses detected equally. All seasonal influenza subtypes were detected. El Salvador and Guatemala reported increased influenza activity at moderate-intensity levels, with the circulation of influenza B/Victoria in El Salvador and all seasonal influenza subtypes in Guatemala. Severity indicators were at low levels. Influenza B (lineage undetermined) viruses continued high in Honduras, with SARI activity at baseline levels. SARS-CoV-2 percent positivity dropped in the subregion, except in Costa Rica. RSV activity was low overall. 

Andean: Influenza activity was low, predominating influenza A(H1N1)pdm09 viruses; influenza B/Victoria and A(H3N2) viruses co-circulated. Overall, influenza detections were very low across reporting countries. SARI activity was increased in Bolivia, with 11.7% influenza-associated SARI. SARS-CoV-2 and RSV activity were low. 

Brazil and Southern Cone: Influenza activity was low, with a slowly increasing trend in recent weeks. Influenza B viruses were more frequently detected, and all seasonal influenza subtypes were detected. In Chile, influenza activity increased to low-intensity levels, and SARI activity was low. Increased SARS-CoV-2 activity was reported in Brazil and Chile. RSV was low among reporting countries. 

Avian Influenza: A summary of the avian influenza situation in the region, case management and recommendations are available at Epidemiological alerts and updates | PAHO/WHO | Pan American Health Organization (paho.org)