Publication Date



Emerging Infectious Diseases


Since May 2023, a novel combination of neuraminidase mutations, I223V + S247N, has been detected in influenza A(H1N1)pdm09 viruses collected in countries spanning 5 continents, mostly in Europe (67/101). The viruses belong to 2 phylogenetically distinct groups and display ≈13-fold reduced inhibition by oseltamivir while retaining normal susceptibility to other antiviral drugs.


Influenza, antiviral, neuraminidase inhibitors, oseltamivir, reduced inhibition, substitution, baloxavir, phenotypic testing, viruses, influenza A(H1N1)pdm09, H1N1, pH1N1, antimicrobial resistance, United States



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