Affiliation:
1. The University of Hong Kong
2. Sanofi Pasteur
3. University of Hong Kong
Abstract
Abstract
Despite decades of research, questions remain about the persistence of neutralising antibodies (nAb) and serological correlates of polio vaccine efficacy. In a cross-sectional study among 299 children in Hong Kong, we estimated that the mean nAb titres against polioviruses type 1, 2 and 3 (PV1, PV2 and PV3) one month after receiving the 4th dose of inactivated polio vaccine (IPV) at 19 months of age were 2,068 (95% credible interval: 1,517 – 2,864), 4,705 (3,439 – 6,436) and 2,758 (1,894 – 4,086), but declined substantially in 4 years to 268 (222 – 325), 751 (630 – 900), and 411 (323 – 521), respectively. Administration of the 5th dose of IPV restored nAb titres among children aged 6-7 years, and the decline in nAb titres was slightly slower with the estimated mean titres of 355 (272 – 462), 538 (427 – 681), and 548 (378 – 786) against PV1, PV2, and PV3 at 4 years post the 5th dose. We estimated that the proportion of children who were seroprotected against PV1, PV2 and PV3 would drop below 90% at: (i) 8.2, 10.8, 8.7 years after the 4th dose; and (ii) 11.6, 11.2, 11.0 years after the 5th dose, highlighting the importance of maintaining populational immune persistence at high nAb levels.
Publisher
Research Square Platform LLC
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