Join on WhatsApp 
Join on Telegram Rabat – According to the World Health Organization (WHO), influenza and other respiratory viruses are currently on a sharp upward trend worldwide, driven in part by the rapid spread of a new influenza variant.
Speaking at a press briefing in Geneva, Wenqing Zhang, head of the WHO’s Global Respiratory Threats Unit within the Department of Epidemic and Pandemic Preparedness, said the current flu season is marked by the emergence and fast expansion of a new subclade of the AH3N2 virus.
“This year is characterized by the emergence and rapid expansion of a new subclade of the AH3N2 virus,” Zhang said, referring to the variant known as J.2.4.1, also called subclade K.
First detected in August in Australia and New Zealand, the variant has since been identified in more than 30 countries.
Zhang noted that current epidemiological data do not point to increased disease severity linked to the new variant, despite a significant genetic evolution of the virus. Influenza viruses are known to evolve continuously, a key reason why flu vaccine compositions are regularly updated.
She explained that the WHO closely monitors these changes, assesses public health risks, and issues vaccine composition recommendations twice a year through its long-established Global Influenza Surveillance and Response System (GISRS), working alongside international experts.
The new variant is not included in the most recent vaccines produced for the northern hemisphere flu season. However, early data suggest that existing seasonal vaccines continue to protect against severe illness and help reduce the risk of hospitalization.
Seasonal flu still bites
Seasonal influenza remains a major global health burden. The WHO estimates that around one billion cases occur each year, including up to five million cases of severe respiratory illness.
Seasonal flu-related respiratory diseases are responsible for as many as 650,000 deaths annually.
Zhang stressed that vaccination remains the most effective line of defense, particularly for high-risk groups and those who care for them. She pointed to early findings from the first study assessing vaccine effectiveness against the new variant, published recently in the United Kingdom.
According to the WHO, the results are “quite promising,” showing around 75%effectiveness against severe disease and hospitalization among children, and about 35 % among adults.
With the holiday season approaching, Zhang warned that increased travel and social gatherings could fuel a further rise in respiratory infections. She urged countries to plan ahead by promoting vaccination and strengthening health system preparedness.
The WHO official also called for stronger year-round laboratory diagnostics and disease surveillance, encouraging countries to take part in the global influenza monitoring network.
GISRS includes influenza surveillance centers in 130 countries and around a dozen reference laboratories worldwide.
Asked whether the US would remain part of the network next year, despite its decision to withdraw from the WHO as of January 22, 2026, Zhang expressed hope for continued cooperation.
“From the perspective of influenza, respiratory surveillance, and preparedness, we certainly need all countries in the world to participate,” she said. “We do not know what the next pandemic strain will be, or when and where it will emerge.”
She added that reducing the time between a virus’s emergence, detection, characterization, and inclusion in vaccines could make a substantial difference in the number of lives saved.
