In a pre-season influenza risk assessment publicly posted in October 2025, Canadian investigators used global genomic and antigenic surveillance data to highlight important mutations in circulating influenza A(H3N2) viruses.

Both viral and host factors have contributed to the intensity of influenza activity during the 2025–2026 season. Some of these factors can be managed, whereas others are largely beyond human control.

In this self-controlled case series study of 11 887 patients, the risk of cardiorespiratory events after RSV-related hospitalization was significantly higher than during the control period.

Human influenza A viruses escape antibody-mediated immunity through changes in the hemagglutinin (HA) and neuraminidase (NA) glycoproteins.

Annual influenza epidemics in the United States cause hundreds of thousands of hospitalizations.

Global influenza and COVID-19 activity stayed low in late October 2025. COVID-19 was more common in northern regions, while influenza spread mainly in tropical areas.

On the European Laboratory Day, held on 5 November, the European Commission marks one year of improved coordination on surveillance data thanks to the EU reference laboratories (EURLs).

In self‐controlled case series studies, laboratory‐confirmed influenza infection was associated with an elevated risk of acute myocardial infarction and stroke during the first 1 month.