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Rapid Disappearance of Poliovirus Type 2 (PV2) Immunity in Young Children Following Withdrawal of Oral PV2-Containing Vaccine in Vietnam
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7 02 2019
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Source: J Infect Dis. 220(3):386-391
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Details:
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Alternative Title:J Infect Dis
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Personal Author:
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Description:Background.
Due to global shortage of inactivated poliovirus vaccine and withdrawal of oral vaccine containing poliovirus type 2 (PV2), a PV2-containing vaccine was not used in Vietnam May 2016 to October 2018. We assessed the population immunity gap to PV2.
Methods.
A cross-sectional survey in children aged 1–18 months was carried out in January 2018. One blood sample per child was analyzed for presence of poliovirus neutralizing antibodies. In children with detectable anti-PV2 antibodies, a second sample was analyzed 4 months later to distinguish between passive (maternally derived) and active (induced by secondary transmission or vaccination) immunity.
Results.
Sera were obtained from 1106/1110 children. Seroprevalence of PV2 antibodies was 87/368 (23.6%) at age 1–7 months, 27/471 (5.7%) at 8–15 months, and 19/267 (7.1%) at 16–18 months. Seroprevalence declined with age in the 1–7 months group; in the 8–18 months group there was no significant change with age. Four months later, 11/87 (14%), 9/27 (32%), and 12/19 (37%) remained seropositive in 1–7, 8–15, and 16–18 months age groups, respectively.
Conclusions.
We found declining immunity to PV2, suggesting Vietnam is at risk for an outbreak of type 2 vaccine-derived poliovirus following virus importation or new emergence.
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Pubmed ID:30869149
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Pubmed Central ID:PMC9069936
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Volume:220
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Issue:3
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