Influenza and other respiratory viruses are increasing sharply, said Dr. Wenqing Zhang, head of the Global Respiratory Threats Unit at the Department of Epidemics and Pandemic Threats Management at the World Health Organization (WHO) told reporters in Geneva that this year has been marked by “the emergence and rapid expansion of a new AH3N2 virus subgroup”.
The new variant – called J.2.4.1 or subclade K – was first noted in August in Australia and New Zealand and has since been detected in more than 30 countries, she said.
DNA shapeshifter
“Current epidemiological data do not indicate an increase in the severity of the disease, although this genetic shift makes a remarkable evolution in the virus,” said Dr. Zhang.
Influenza viruses are constantly evolving, she explained, which is why the flu vaccine composition is continuously updated.
“WHO tracks these changes, assesses associated public health risks and makes recommendations on vaccine composition twice a year through a long-standing global system – the Global Influenza Surveillance and Response System (GISRS), in collaboration with other global experts,” said Dr. Zhang.
The new variant (hasn’t been incorporated into?) is not part of the composition of the latest vaccines produced for the flu season in the northern hemisphere, the WHO expert explained.
Still, “early evidence suggests that current seasonal vaccines continue to offer protection against serious illness and reduce the risk of hospitalization,” she said.
The WHO estimates that there are about one billion cases of seasonal influenza annually, including up to five million cases of severe respiratory disease. Up to 650,000 deaths each year are due to seasonal influenza-related respiratory illness.
Advice on risk reduction
“Vaccination remains our most effective defense, including against stray strains, especially for high-risk populations and those who care for them,” insisted Dr. Zhang.
The WHO expert shared the results of an early assessment of the vaccine’s effectiveness against the new variant, published in the UK a few weeks ago.
“It’s pretty promising,” she said, pointing to data showing the vaccine is about 75 percent effective against severe illness and hospitalization in children and about 35 percent among adults.
Dr. Zhang warned that the upcoming holiday season may bring a further increase in respiratory diseases. “Advanced planning and preparedness efforts, including encouraging vaccination uptake and strengthening health system preparedness, are strongly recommended,” she said.
The WHO expert advised countries to strengthen laboratory diagnostics and year-round disease surveillance and participate in WHO’s GISRS surveillance network.
Global monitoring remains key
The network includes influenza centers in 130 countries as well as a dozen reference laboratories.
Asked whether the US will remain a member of the network next year despite the country’s decision to leave the WHO, effective January 22, 2026, Dr. Zhang that “from the influenza perspective, from a respiratory surveillance and preparedness perspective, we would certainly need all countries in the world to participate in the surveillance, preparedness and a response to the next influenza virus, because we know the next influenza virus and other influenza viruses. when and where it would appear”.
“And that time between emergence and being picked up and characterized and put into vaccines … that would make a big difference in terms of the number of lives that could be saved,” she concluded.
