The current flu season, which has been relatively mild, is projected to escalate significantly in the coming weeks due to the emergence of a new strain. Medical experts caution that while the existing vaccine remains the best protection, its effectiveness may be compromised against this new variant.
According to data from the U.K. National Health Service, the newly identified subclade K has led to the highest rate of flu hospitalizations recorded at this time of year. This strain first appeared in Australia towards the end of its flu season and has since been detected in Japan and the United States. Lisa Sollot, who coordinates the respiratory disease program for the Virginia Department of Health, noted that this strain is linked to rising hospitalization rates.
Current statistics indicate that the vaccine available in the U.K. and the U.S. has an effectiveness rate of only about 32-39% in preventing flu infections. However, it shows a higher effectiveness of 72-75% among children, as reported by the University of Virginia.
Frederick G. Hayden, a professor at the University of Virginia School of Medicine and a member of its Division of Infectious Diseases and International Health, co-authored a study published in the Journal of the American Medical Association. He emphasized that the emergence of subclade K, a subtype of the strain responsible for last flu season’s severe impact, raises concerns for the current season. He stated, “The 2024-25 influenza season, largely due to influenza A H1N1 and H3N2 viruses, was associated with high severity across all age groups, including an exceptionally high number of pediatric deaths.”
A report from the Centers for Disease Control and Prevention (CDC) on December 11, 2023, corroborates these concerns, indicating that the virus is accelerating in the U.S. Hayden added, “Unfortunately, we are seeing the circulation of a new variant of the H3N2 virus for which our vaccines may be somewhat less effective. However, available vaccines will reduce the risk of serious illness and potentially the spread of this virus.”
Sollot highlighted the unusual nature of consecutive high-severity flu seasons. “Low vaccination rates combined with subclade K’s emergence may potentially lead to a severe season, but we really can’t say exactly how severe,” she stated in an interview.
In Virginia, current vaccination rates across all age groups stand at about 28%. The rate is particularly low among children aged 5-17, where it drops to 20.6%. In contrast, individuals aged 50 and older have a vaccination rate of 39.8%.
The CDC’s data from the previous flu season revealed alarming statistics: approximately 90% of children who died from the flu were unvaccinated, and half of these children had no underlying health conditions. Sollot remarked, “Those are really shocking statistics for the season. Everybody get vaccinated, wash your hands, and stay home when you’re sick.”
The CDC continues to recommend influenza vaccination for everyone aged 6 months and older, with only rare exceptions. As the flu season progresses, health officials stress the importance of vaccination and preventive measures to mitigate the potential impact of the new strain.
