Key result
Following the introduction of the EV-A71 vaccine, only 3 EV-A71-positive samples were detected among 6,868 enterovirus-positive HFMD cases in Guangzhou from 2019 to 2021.
Why the study?
The seroprevalence of EV-A71 following vaccine application in 2016 and its association with EV-A71 epidemic activity had been rarely studied.
Does the inactivated EV-A71 vaccine provide long-term immunity and reduce epidemic activity of EV-A71 in the susceptible population?
Observational (n=167,920)
Does the inactivated EV-A71 vaccine provide long-term immunity and reduce epidemic activity of EV-A71 in the susceptible population?
The inactivated EV-A71 vaccine provides long-term immunity up to 49 months, likely contributing to the low epidemic activity of EV-A71 in Guangzhou from 2019 to 2021.
EV-A71 circulation appears reduced post-vaccination in Guangzhou; leaves open durability of population immunity and need for ongoing surveillance.
Enterovirus A71 (EV-A71) is a significant hand-foot-mouth disease (HFMD) etiology. The inactivated EV-A71 vaccines were approved in China in 2016. However, the seroprevalence of EV-A71 after the vaccine application and its potential association with the EV-A71 epidemic in the population are rarely studied. In this study, we analyzed the incidence of EV-A71 infection and seroepidemiology in Guangzhou City, China. From 2019 to 2021, 167,920 clinically confirmed HFMD cases were reported in Guangzhou. In 6,868 enterovirus-positive samples, Coxsackievirus A6 and Coxsackievirus A16 were dominant genotypes, and only 3 EV-A71-positive samples were detected, highlighting the deficient epidemic activity of EV-A71. Microneutralization assay was performed on 1,000 representative serum samples. Notably, the seroprevalence and geometric mean titer (GMT) decreased significantly in 2020, and that in the < 3-year age group were increased and even higher than that in 3-5-year age group in 2019 and 2021, which was contrary to our previous surveillance result and other studies in Guangzhou. Furthermore, a moderate decline of GMT level was observed following the vaccination, but the seropositive serums were still detected for 49 months after second immunization, suggesting the long-term persistence of the immunity. Our seroepidemiology study revealed relatively higher neutralizing antibody activity in the susceptible population after the EV-A71 vaccine was adopted in 2016 in Guangzhou. It may be one of the reasons for the lower epidemic activity of EV-A71 in Guangzhou from 2019 to 2021.
No takes yet. Share an insight, caveat, or question.
Lian et al. (2023) conducted an observational in Hand-foot-mouth disease (HFMD) / Enterovirus A71 infection (n=167,920). EV-A71 vaccination was evaluated on Incidence of EV-A71 infection and seroprevalence. Following the introduction of the EV-A71 vaccine, only 3 EV-A71-positive samples were detected among 6,868 enterovirus-positive HFMD cases in Guangzhou from 2019 to 2021.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: