A flu strain that surfaced during the summer months is driving widespread concern among global health authorities, as it has led to “unprecedented” outbreaks in Japan and rising cases in Canada and the U.K. While other nations release frequent updates, the United States has gone nearly two months without detailed flu insights from the Centers for Disease Control and Prevention, leaving questions about how the strain may be circulating domestically.
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Growing Global Alarm Over the Emergence of a New H3N2 Strain
As the start of flu season unfolds, international health experts are increasingly focused on a newly emerged version of H3N2 that appeared in June, several months after decisions were finalized regarding which strains would be included in this year’s flu vaccines. This delayed emergence has created challenges, as the strain is now responsible for significant outbreaks in countries such as Canada and the U.K., where hospitals are already reporting increased admissions linked to this early flu wave.
During a media briefing, Dr. Wenqing Zhang, head of the World Health Organization’s Global Respiratory Threats Unit, noted that “Since it emerged, it’s rapidly spreading and predominating in some countries so far in the Northern Hemisphere.” Researchers say this version of H3N2 has undergone considerable genetic changes, making it notably different from the strain used in current vaccines. Antonia Ho, a consultant in infectious diseases at Scotland’s University of Glasgow, stated in a media release that the circulating strain “acquired 7 new mutations over the summer,” adding that this “means the virus is quite different to the H3N2 strain included in this year’s vaccine.”
Health officials in the U.K. are expressing concern as infections rise at a pace well above last year’s levels. The head of the U.K.’s National Health Service, James Mackey, said the nation is heading “into what looks set to be a cruel winter, with flu cases being triple what they were this time last year.” Similar patterns are being reported in Canada, where virologist Angela Rasmussen of the University of Saskatchewan highlighted increasing flu activity. H3N2 is known to cause more severe illness than many other influenza strains, with elevated risks for older adults. Japan is also in the midst of a fast-moving and unusually intense flu season that Rasmussen described as “unprecedented.”
According to reporting from Japanese outlet Nippon TV, flu cases in Tokyo as of November 4 had climbed to nearly six times the number documented during the same period last year, based on data from the Japanese Ministry of Health, Labor and Welfare. The outlet also noted that more than 2,300 schools and day cares were partially or fully closed because of the flu outbreak. Rasmussen responded to these developments by saying, “These are not good signs.”
Questions Rise About Activity Inside the United States
H3N2 belongs to the influenza A category, and while anecdotal accounts suggest that individuals in many regions of the U.S. have tested positive for flu A, national visibility remains limited. The absence of updated, comprehensive flu reports is linked to the government shutdown, which has prevented the CDC from releasing a nationwide update since September 26.
Even if the CDC resumes operations soon, further delays may continue due to steep staffing cuts. Dr. William Schaffner, an infectious diseases specialist at Vanderbilt University Medical Center in Nashville, warned that the “hollowing out” of the agency could slow data gathering and analysis. Earlier in the year, the Department of Health and Human Services announced plans to reduce up to 10,000 public health positions. According to Schaffner, “We are going to be dependent on state laboratories and academic laboratories for these investigations and report them out.” He explained that the resulting information “will not be as comprehensive, centralized and as quickly analyzed and communicated from the CDC as we have had in previous years.”
Effectiveness of the Current Flu Vaccine
Each February, global health organizations and vaccine manufacturers select strains for Northern Hemisphere flu shots using trends from the Southern Hemisphere. This year’s vaccine targets three variants: two influenza A strains and one influenza B strain. While the annual shot does not eliminate the risk of infection, its primary purpose is to reduce the severity of illness. Last year, data showed that the vaccine was up to 55% effective in preventing hospitalizations among adults.
Recent findings in the U.K. suggest that this year’s flu shot offers up to 40% protection against hospitalization. Despite the mismatch between the vaccine strain and the newly mutated H3N2 variant, Schaffner urged the public to get vaccinated. “All of the data over previous decades shows that even if there is not a close match, use of the vaccine continues to prevent hospitalizations, intensive care unit admissions and continues to help keep people out of the cemetery,” he said.
Rising Concerns as New Flu Strain Spreads Across Countries Conclusion
The new H3N2 strain is advancing quickly across several nations, leading to early, severe, and widespread outbreaks that have prompted heightened global concern. With limited visibility in the U.S. due to delayed reporting and staffing cuts, health experts emphasize the importance of remaining prepared and taking available preventive measures, including vaccination.
