Evaluation of a two-dose administration of live oral poliovirus vaccine for wild and virulent vaccine-derived poliovirus type 1, 2, 3 strains in Japan

Department of Virology, Toyama Institute of Health, Nakataikoyama, Imizu-shi, Toyama, Japan.
Infectious Diseases (Impact Factor: 1.5). 02/2008; 40(3):247-53. DOI: 10.1080/00365540701596003
Source: PubMed


We evaluated the efficacy of Japan's vaccination policy, a 2-dose administration of live oral poliovirus vaccine (OPV) against wild and virulent vaccine-derived poliovirus (VDPV) type 1, 2, 3 strains, by investigating the neutralizing antibody titers of residents in Toyama Prefecture, Japan. Seropositivities against the virulent type 1 and 2 strains were more than 90%, but the values against the virulent type 3 strains were approximately 60%. Also, while geometric mean antibody titers against virulent type 1 and 2 strains were more than 180, those against the virulent type 3 strains were 58-59, and 9-12, in particular, at 10 to 19 y of age. A booster dose of the vaccine for the type 3 virus is recommended for adolescents. However, high herd immunity against type 1, 2 and 3 viruses has been maintained for these 22 y, although the seropositivity against type 3 virus was always lower than other types. Our results suggest that Japan's vaccination policy might be enough to prevent an epidemic of poliomyelitis caused by wild and virulent VDPV type 1, 2, 3 strains, even though the titers against type 3 viruses were the lowest.

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