Seroprevalence of EV-A71 neutralizing antibodies following the 2011 epidemic in HCMC, Vietnam.

Fang-Lin Kuo,Wen-Chiung Chang,Le Nguyen Thanh Nhan,Truong Huu Khanh,Wan-Yu Chung,Min-Shi Lee,Le Quoc Thinh,Nguyen Thanh Hung,Shu-Ting Luo,Scott C Weaver

doi:10.1371/journal.pntd.0008124

Fang-Lin Kuo, Wen-Chiung Chang + Show 8 more

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https://doi.org/10.1371/journal.pntd.0008124

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Abstract

Enterovirus-A71 (EV-A71) cyclically causes hand-foot-mouth disease (HFMD) epidemics in Asian children. An EV-A71 epidemic occurred in Southern Vietnam in 2011, but its scale is not clear. We collected residual sera from non-HFMD Vietnamese inpatients in 2012–2013 to determine seroprevalence of EV-A71 neutralizing antibodies, and measured cross-reactive neutralizing antibody titers against three EV-A71 genogroups. About 23.5% of 1-year-old children in Southern Vietnam has been infected by EV-A71, and the median age of infection was estimated to be 3 years. No significant antigenic variation could be detected among the three EV-A71 genogroups. The high seroprevalence of EV-A71 neutralizing antibody in children living in southern Vietnam indicates the necessity of introducing EV-A71 vaccines in southern Vietnam, particularly for children under 6 months of age. Moreover, it is critical to understand EV-A71 disease burden for formulating national vaccination policy.

Highlights

Enterovirus-A71 (EV-A71), a member of the Picornaviridae, is a non-enveloped, singlestranded, positive-sense RNA virus and was first isolated in 1969 in California, USA [1,2]
The high seroprevalence of EV-A71 neutralizing antibody in children living in southern Vietnam indicates the necessity of introducing EV-A71 vaccines in southern Vietnam, for children under 6 months of age
The results of our study demonstrate that about 50% of young children under 3 years of age were infected during the 2011 epidemic in southern Vietnam

Summary

Introduction

Enterovirus-A71 (EV-A71), a member of the Picornaviridae, is a non-enveloped, singlestranded, positive-sense RNA virus and was first isolated in 1969 in California, USA [1,2]. EV-A71 could be classified into 3 major genogroup (A, B and C) [3] and newly discovered genogroups (D, E and F) [4]. Genogroup A includes the prototype EV-A71 first isolated in California. Genogroup B has five genotypes (B1~B5) which have been circulating in Asia [3]. Genogroup C comprises five genotypes (C1~C5) and C3—C5 recently have been involved in epidemics in Asia and Europe. Genotype C4 could be further classified as subgenotype C4a and C4b [5]

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