Short-term dynamic changes in neutralizing antibodies against enterovirus 71 after vaccination

Abstract

Background: Short-term dynamic changes in neutralizing antibodies against EV71 and EV71-IgM after inactivated EV71 vaccine injection are unknown.

Methods: This study was designed as a randomized, open-label study and was registered at ClinicalTrials.gov (NCT03278132). In total, 120 healthy infants aged 6-35 months were randomized 1:1:1 to provide a second blood sample on day 10, day 20, or day 30 after the first vaccine dose, respectively.

Results: According to the per-protocol set, a rapid immune response against EV71 was observed 10 days after the first EV71 vaccine dose, with antibody titers ≥1:8 in 89.19% of participants (95% CI: 74.58-96.97%) on day 10, in 80.65% (95% CI: 62.53-92.55%) on day 20, in 66.67% (95% CI: 49.03-81.44%) on day 30, and in 100% (95% CI: 96.52%-.) on day 60. Based on an ELISA, the percentages of participants positive for EV71-IgM on day 0 and day 60 were 1.71% (2 out of 117) and 82.86% (87 out of 105), respectively.

Conclusions: The EV71 vaccine could be used for contingency vaccination to further control EV71-associated disease outbreaks. Caution should be taken in using the EV71-IgM test for rapid EV71 infection diagnosis after EV71 vaccine administration.

Clinical trial registration: ClinicalTrials.gov NCT03278132.

Keywords: EV71 vaccine; EV71-IgM; rapid response.

Figures

Figure 1.

Trial profile.

Figure 2.

Reverse cumulative curves for EV71 neutralizing antibody titers of participants included in the per-protocol-set on at pre-vaccination (day 0), post-first vaccination (day 10, day 20, and day 30), and 30 days post the second dose.

Figure 2.

Reverse cumulative curves for EV71 neutralizing antibody titers of participants included in the per-protocol-set on at pre-vaccination (day 0), post-first vaccination (day 10, day 20, and day 30), and 30 days post the second dose.