WASHINGTON, United States (CMC) — The Pan American Health Organization (PAHO) is urging countries in the Americas, including the Caribbean, to adjust their health service preparedness and response plans as the Northern Hemisphere enters the season of increased influenza and other respiratory virus circulation.

PAHO said based on a recent epidemiological alert, the combination of vaccination, surveillance, hospital preparedness, timely access to diagnosis and treatment, and personal preventive measures are crucial to reducing disease burden, protecting vulnerable populations and avoiding potential strain on health systems.

It said global influenza activity, driven by influenza A viruses, continues to rise and that a sustained increase is being observed, particularly in North America, while activity remains relatively low in the rest of the Americas.

In the Caribbean and Central America, influenza A(H1N1)pdm09 predominates, while in Canada and the United States, there is greater circulation of the A(H3N2) subtype, including a progressive increase in subclade K, already widely detected in Europe and Asia.

PAHO said that although no significant increase in severity has been observed so far, A(H3N2)-dominated seasons tend to affect older adults more severely and that preliminary evidence suggests that the current vaccine maintains protection levels similar to previous seasons, particularly in preventing severe cases and hospitalisations.

PAHO is urging countries to strengthen surveillance for influenza, RSV, and SARS-CoV-2, ensure continuous data reporting and maintain regular sample submission for sequencing to detect variants that could alter virus transmission or severity.

It is also reminding countries that unusual respiratory events, such as severe cases with no identified cause or outbreaks outside expected circulation periods, should be promptly investigated and reported under the International Health Regulations (IHR).

PAHO recommended reviewing and updating national clinical management guidelines as needed, strengthening access to early diagnosis and ensuring the availability of antivirals for those at higher risk of complications.

Health services should prepare for a potential increase in hospitalisations during the winter months when multiple respiratory viruses circulate simultaneously.

PAHO reiterated the importance of vaccination against influenza, COVID-19 and RSV, especially for older adults, people with chronic conditions, pregnant women, young children, and healthcare workers.

For COVID-19, priority groups are recommended to receive booster doses every six to 12 months.

PAHO said simple measures such as handwashing, respiratory etiquette and staying home when experiencing fever or symptoms are essential to limit transmission.