Oligoadenylate synthetase 3 S381R gene polymorphism is associated with severity of EV71 infection in Chinese children.

•The carriage frequency of OAS3 S381R CC genotypes and the occurrence of C allele in severe EV71infected cases were significantly higher than in mild cases.•Severe cases had significant higher levels of IFN-γ in GC + GG genotypes compared to CC genotype.•Carrying C allele of the OAS3 S381R gene could be a susceptibility factor in the development of severe EV71 infection.