According to Zhang, the new strain of the AH3N2 flu was first detected in August in Australia and New Zealand and has since spread to more than 30 countries. Currently, flu and other respiratory viruses are actively circulating worldwide.
Genetic Changes in the Virus
Zhang noted that the available data do not indicate an increased severity of illnesses; however, the genetic changes in the virus represent a significant stage in its evolution. "The flu constantly mutates, which requires regular updates to vaccine formulations," she explained.
The WHO is monitoring these changes and assessing public health risks, developing vaccine composition recommendations twice a year through the Global Influenza Surveillance and Response System (GISRS), collaborating with international experts, Zhang added.
The new strain was not included in the vaccines produced for the current season in the Northern Hemisphere. Nevertheless, initial data show that existing vaccines remain effective in preventing severe forms of the disease and reducing the risk of hospitalization.
According to WHO estimates, approximately one billion cases of seasonal flu are reported worldwide each year, including up to five million cases of severe respiratory illnesses. Respiratory complications caused by seasonal flu lead to approximately 650,000 deaths annually.
Recommendations for Risk Reduction
Zhang emphasizes that vaccination remains the most effective way to protect, especially for at-risk groups and those caring for them. She also shared preliminary results of an assessment of vaccine effectiveness against the new variant published in the UK, where effectiveness is about 75% for children and approximately 35% for adults in preventing severe disease and hospitalization.
The expert warns that the holiday season may trigger a new surge in respiratory illnesses. "It is important to plan and prepare in advance, including actively promoting vaccination and strengthening healthcare systems," she added.
Additionally, Zhang recommends that countries enhance laboratory diagnostics and continuously monitor diseases by participating in the GISRS network.
The Need for Global Monitoring
The GISRS includes flu centers from 130 countries and more than ten reference laboratories.
When asked about the future participation of the United States in this network after its withdrawal from the WHO in 2026, Zhang noted: "The participation of all countries in influenza and other respiratory virus surveillance and response is crucial, as it is difficult to predict where and when a new pandemic strain may emerge." She added that the time between emergence, identification, and inclusion in vaccines is critical for saving lives.
