Flu Season Arrives Earlier Than Expected In US As Mutated Virus Spreads

Flu Season Arrives Earlier Than Expected in US as Mutated Virus Spreads The flu season is gathering momentum in the United States months ahead of schedule, with a mutated strain spreading in parts of the country and raising concerns among health experts about the potential impact on the population. The early increase in flu activity comes as some Americans may not yet be considering their annual influenza vaccination, which health authorities recommend to help reduce the risk of severe illness and complications. The emergence of a changed virus has added uncertainty to the season, as health officials monitor its spread and assess how well existing immunity and available vaccines may protect people against infection. According to the US Centers for Disease Control and Prevention, influenza activity has been increasing since late August and early September, with the highest levels reported along the West Coast. The agency said activity remained relatively low nationally in its latest surveillance update, despite being higher than typically observed at this time of year. The predominant strain identified so far is influenza A(H1N1), including a version carrying a mutation known as G155E. Researchers are investigating whether the change could reduce existing immune protection, particularly among younger people who may have had less recent exposure to the strain. Doctors have urged Americans aged six months and older to receive their seasonal flu vaccination. The 2026–2027 US vaccine targets H1N1, H3N2 and an influenza B strain, although protection can vary depending on how well the vaccine matches viruses circulating during the season. Health experts caution that an early start does not necessarily mean the flu season will be more severe than usual. However, the rise in cases has prompted calls for people not to delay preventive measures while scientists continue monitoring the virus.