Chon I, Wagatsuma K, Saito R, Tang JW, Isamu S, Su. Detection of influenza A(H3N2) viruses with polymerase acidic subunit substitutions after and prior to baloxavir marboxil treatment during the 2022-2023 influenza season in Japan. Antiviral Res. 2024 Jul 3:105956
Baloxavir marboxil (baloxavir), approved as an anti-influenza drug in Japan in March 2018, can induce reduced therapeutic effectiveness due to PA protein substitutions. We assessed PA substitutions in clinical samples from influenza-infected children and adults pre- and post-baloxavir treatment, examining their impact on fever and symptom duration. During the 2022-2023 influenza season, the predominant circulating influenza subtype detected by cycling-probe RT-PCR was A(H3N2) (n=234), with a minor circulation of A(H1N1)pdm09 (n=10). Of the 234 influenza A(H3N2) viruses collected prior to baloxavir treatment, 2 (0.8%) viruses carry PA/I38T substitution. One virus was collected from a toddler and one from an adult, indicating the presence of viruses with reduced susceptibility to baloxavir, without prior exposure to the drug. Of the 54 paired influenza A(H3N2) viruses collected following baloxavir treatment, 8 (14.8%) viruses carried E23K/G, or I38M/T substitutions in PA. Variant calling through next-generation sequencing (NGS) showed varying proportions (6 to 100 %), a polymorphism and a mixture of PA/E23K/G, and I38M/T substitutions in the clinical samples. These eight viruses were obtained from children aged 7-14 years, with a median fever duration of 16.7 hours and a median symptom duration of 93.7 hours, which were similar to those of the wild type. However, the delayed viral clearance associated with the emergence of PA substitutions was observed. No substitutions conferring resistance to neuraminidase inhibitors were detected in 37 paired samples collected before and following oseltamivir treatment. These findings underscore the need for ongoing antiviral surveillance, informing public health strategies and clinical antiviral recommendations for seasonal influenza.
See Also:
Latest articles in those days:
- Intranasal influenza virus-vectored vaccine offers protection against clade 2.3.4.4b H5N1 infection in small animal models 4 hours ago
- Mapping of stakeholders in avian influenza surveillance in Canada 16 hours ago
- [preprint]Population Immunity to Hemagglutinin Head, Stalk and Neuraminidase of Highly Pathogenic Avian Influenza 2.3.4.4b A(H5N1) viruses in the United States and the Impact of Seasonal Influenza on 1 days ago
- Airborne Influenza Virus Surveillance Platform Using Paper-Based Immunosensors and a Growth-Based Virus Aerosol Concentrator 1 days ago
- [preprint]A Human H5N1 Influenza Virus Expressing Bioluminescence for Evaluating Viral Infection and Identifying Therapeutic Interventions 2 days ago
[Go Top] [Close Window]