Hallmann, EwelinaMasny, AleksanderPoznańska, AnnaPozo Sanchez, FranciscoCasas Flecha, InmaculadaBrydak, Lidia Bernadeta2024-03-222024-03-222024-03-06Med Sci Monit. 2024 Mar 6:30:e942125.http://hdl.handle.net/20.500.12105/19040Background: According to the WHO, up to 650 000 people die each year from seasonal flu-related respiratory illnesses. The most effective method of fighting the virus is seasonal vaccination. However, if an infection does occur, antiviral medications should be used as soon as possible. No studies of drug resistance in influenza viruses circulating in Poland have been systematically conducted. Therefore, the aim of the present study was to investigate the drug resistance and genetic diversity of influenza virus strains circulating in Poland by determining the presence of mutations in the neuraminidase gene. Material/Methods: A total of 258 clinical specimens were collected during the 2016-2017, 2017-2018, and 2018-2019 epidemic seasons. The samples containing influenza A and B were analyzed by RT-PCR and Sanger sequencing. Results: Differences were found between the influenza virus strains detected in different epidemic seasons, demonstrating the occurrence of mutations. Influenza A virus was found to be more genetically variable than influenza B virus (P<0.001, Kruskal-Wallis test). However, there was no significant difference in the resistance prevalence between the influenza A subtypes A/H1N1/pdm09 (4.8%) and A/H3N2/ (6.1%). In contrast, more mutations of drug-resistance genes were found in the influenza B virus (P<0.001, chi-square test). In addition, resistance mutations appeared en masse in vaccine strains circulating in unvaccinated populations. Conclusions: It seems important to determine whether the influenza virus strains tested for drug resistance as part of global influenza surveillance are equally representative of viruses circulating in populations with high and low vaccination rates, for all countries. Our results suggest that countries with low levels of influenza immunization may constitute reservoirs of drug-resistant influenza viruses.engVoRhttp://creativecommons.org/licenses/by-nc-nd/4.0/Sequence Analysis, RNAInfluenza A virusInfluenza B virusPolandInfluenza, HumanInfluenza A Virus, H1N1 SubtypeHumansSeasonsPolandInfluenza A Virus, H3N2 SubtypeInfluenza B virusVaccinationMutationAttribution-NonCommercial-NoDerivatives 4.0 Internacional3844673630e94212510.12659/MSM.9421251643-3750Medical science monitor : international medical journal of experimental and clinical researchopen access