MercoPress. South Atlantic News Agency

PAHO urges region to prepare for Northern Hemisphere respiratory virus surge

Europe is facing unusually early and severe flu outbreaks

The Pan American Health Organization (PAHO) has issued an epidemiological alert, urging countries in the Americas to adjust their preparedness in anticipation of the upcoming winter season in the Northern Hemisphere. The alert highlights the imminent increased circulation of influenza, Respiratory Syncytial Virus (RSV), and SARS-CoV-2 (Covid-19).

PAHO emphasized that a comprehensive strategy — combining vaccination, strengthened surveillance, hospital readiness, and timely treatment — is crucial to protecting vulnerable populations and preventing health system overload.

Canada and the United States are seeing a greater presence of the A(H3N2) subtype, including the K subclade, which has also been detected in Europe and Asia. PAHO warns that seasons dominated by A(H3N2) tend to affect older people more severely.

In the Caribbean and Central America, circulation is dominated by the A(H1N1)pdm09 virus.

Preliminary evidence suggests the current flu vaccine maintains comparable protection levels to previous seasons, especially in preventing severe cases and hospitalizations.

The Southern Hemisphere recently concluded its winter season with a 29% increase in severe cases of acute respiratory infection compared to 2024.

The RSV had a significant impact on infants under six months of age.

In the case of influenza, the malady primarily affected older adults, with circulation shifting from A(H1N1)pdm09 to A(H3N2), but without an increase in severity. The new A(H3N2) subclade K had not been detected in South America as of early November.

Regarding Covid-19, detection peaked in early 2025, with the XFG variant becoming predominant, though without evidence of increased severity.

PAHO is urging member states to strengthen surveillance of all three key viruses and ensure timely data reporting, including the regular submission of samples for genetic sequencing to detect new variants.

The organization suggested updating clinical management guidelines and ensuring access to antivirals for high-risk individuals, preparing health services for a possible surge in hospitalizations due to the simultaneous circulation of multiple viruses, reiterating the importance of vaccination against influenza, Covid-19, and RSV, particularly among high-risk groups (older adults, chronic patients, pregnant women, young children, and healthcare workers).

Meanwhile, Europe is facing unusually early and severe flu outbreaks, with facemasks in many places, driven by the A(H3N2) subclade K variant.

The World Health Organization (WHO) noted that flu activity started three to six weeks ahead, disrupting epidemiological projections.

The outbreak is severely stressing healthcare infrastructure, with flu-related hospital admissions in the United Kingdom rising sharply, logging a 56% year-on-year increase in recent weeks. Authorities have advised immediate isolation upon symptom onset.

In Spain, the Generalitat de Catalunya has made the use of face masks mandatory in all health and social centers, after flu cases doubled in a single week, forcing the region into a “high level of transmission.”

Scientific concern surrounds the A(H3N2) subclade K variant due to its ability to incorporate mutations, allowing it to partially evade immune responses, including those provided by available vaccines. Experts emphasize that while effectiveness may be slightly compromised, vaccination remains crucial to significantly reducing the risk of severe complications and hospitalization.