PAHO issues regional influenza update for epidemiological week 12

No region in the U.S. or Canada reported widespread influenza activity in epidemiological week 12, according to an April 2 report by the Pan American Health Organization.

According to the PAHO, there was a general decrease in multiple influenza surveillance indicators in North America in week 12, including the proportion of positive samples tested for influenza, the number of hospitalizations due to influenza and the influenza-like-illness consultation rate. The proportion of influenza B virus detections rose during the week. Influenza B has been increasing in the last few weeks and is the dominant circulating influenza virus in the U.S. and Canada.

In Mexico, influenza A(H3N2) is the most prevalent circulating virus.

Central America and the Caribbean reported similar respiratory virus activity compared to the previous few weeks, with co-circulation of influenza B, influenza A(H3N2) and influenza A (H1N1)pdm09. Respiratory syncytial virus was the predominant circulating virus in some of the countries of this sub-region.

Most countries in South America reported an increase in acute respiratory infection in week 12, though most countries remain within expected levels for the time of year. RSV was the predominant circulating virus in the Andean countries, with the exception of Ecuador. Ecuador reported the co-circulation of influenza A(H3N2) and RSV.

Adenovirus circulated predominantly in the Southern Cone, exempt for in Paraguay where influenza A(H3N2) was the predominant virus.

In Brazil, RSV continued to circulate in the Northeastern and Southeastern parts of the country. There was very low overall viral circulation in the rest of Brazil.