Recent reports from the Centers for Disease Control and Prevention (CDC) have highlighted the emergence of new ‘dual mutant’ strains of H1N1 influenza in the United States. These strains, with genetic changes known as I223V and S247N, have raised concerns about their impact on the effectiveness of the main flu antiviral medication used in hospitals.
The CDC’s findings, published in the Emerging Infectious Diseases journal, reveal that at least two cases of the dual mutant strains have been identified in U.S. patients. Researchers in Hong Kong initially detected these mutations, which have been shown to potentially reduce the sensitivity of the flu treatment oseltamivir, commonly known as Tamiflu.
While the mutations may affect the efficacy of oseltamivir, they do not seem to impact other anti-influenza medications, such as baloxavir marboxil. The CDC has stated that there are currently no immediate changes recommended for clinical care in response to these findings.
Despite the global spread of these dual mutant strains across multiple continents, the CDC report suggests that they remain relatively rare at this time. Since their initial detection in British Columbia, Canada, in May 2023, a total of 101 sequences have been submitted to the global virus database.
Flu vaccination continues to be emphasized as a key preventive measure against these mutated viruses. While the full extent of their impact on public health remains to be seen, ongoing monitoring and research are essential to address the evolving landscape of influenza strains.
