To evaluate the effect of vaccine and provide scientific evidence for prevention and control of influenza virus, this study aims to analyze the characteristics of genomic variation of influenza A (H1N1) pdm09 viruses in Inner Mongolia.

The 16 viral strains were selected randomly according to the influenza A (H1N1) pdm09 viruses isolated from network laboratories in Inner Mongolia, 2013-2017. The hemagglutinin(HA) and neuraminidase(NA) genomic sequences were obtained by using RT-PCR and sequencing, and genomic characteristics were analyzed via bioinformatics.

Compared to the A/California/07/2009 vaccine strain, the relatively obvious variation of antigen of influenza A (H1N1) pdm09 viruses in Inner Mongolia since 2014, and the vaccine provided a poor protection to influenza A (H1N1) pdm09 virus infection, while the A/Michigan/45/2015 vaccine strain recommended by WHO recently has a satisfactory protective effects. Several viral isolates from Inner Mongolia increased the binding force of virus in human upper respiratory tract because of D222N and D222G substitution within HA. E119K and H275Y substitution within NA gene of viral strains, suggesting that the viruses were resistant to NA inhibitors.

The influenza A (H1N1) pdm09 viruses had gradual variations as time went on, and the WHO recommended vaccine was relatively lagging. Virulent strains and drug-resistant strains appeared in the population, and the genetic characteristics of influenza virus surveillance should be strengthened to find the new mutants of virus in time, which provide evidence for the prevention and control of influenza.

Influenza A (H1N1) pdm09 virus; Complete genome; Genetic characteristics