new Flu Strain Dominating UK Cases May Signal Harsh Winter, Despite Vaccine Protection
LONDON – A newly emerged influenza A(H3N2) subclade, designated K, is driving an early and significant surge in flu cases in the United Kingdom, raising concerns about a possibly severe winter flu season in both the UK and North America. Health officials in the UK have already announced the early start to their flu season, with the majority of cases now attributed to subclade K.Hospitals in the region are bracing for a ample influx of patients.
The emergence of subclade K presents a challenge to this year’s flu vaccines, as the strain wasn’t fully anticipated during vaccine development. Researchers are working to better understand the characteristics of the variant and its potential impact on vaccine effectiveness. According to recent data, the vaccine is estimated to be 70% to 75% effective at preventing flu hospitalizations in children and 30% to 40% effective in adults, even with the mismatch.
“These results provide reassuring evidence that this season’s flu vaccines currently offer significant protection to children and adults, despite concerns about the new subclade,” stated Jamie Lopez Bernal, consultant epidemiologist for Immunization at UKHSA, in a recent agency statement.
Despite the partial mismatch, vaccines remain a crucial defence against the flu, offering protection against other circulating strains and mitigating the risk of severe illness. Public health experts emphasize the importance of vaccination alongside preventative measures such as practicing good hygiene, staying home when sick, and wearing well-fitting, high-quality masks (KN95 or N95) in higher-risk environments.
The situation is further complicated by recent disruptions to public health infrastructure in the United states. Dramatic funding cuts and layoffs at the Centers for Disease Control and Prevention (CDC) and other health agencies,overseen by President Donald Trump and Health Secretary Robert F.Kennedy Jr., alongside the departure of senior health officials, may hinder containment efforts.
While the possibility remains that subclade K will not spread widely in North America due to the presence of other circulating flu variants, experts suggest the odds of that outcome are diminishing. Researchers are actively monitoring the situation to determine the dominant strains circulating for the NH 2025-2026 season.
