Incidence of Infection of Enterovirus 71 and Coxsackieviruses A6 and A16 among Household Contacts of Index Cases in Dong Thap Province, Southern Vietnam.

C Q Hoang,N X Ho,K T Nguyen,L T Hoang,H Clapham,L T Phan,T T M Pham,H D Nguyen,H T Nguyen,T H T Vu,T T T Nguyen,Frederick D Quinn

doi:10.1155/2020/9850351

C Q Hoang, N X Ho + Show 10 more

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https://doi.org/10.1155/2020/9850351

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Abstract

Background Scarce information exists about immunity to hand, foot, and mouth disease (HFMD) among household contacts of index cases in Vietnam and what that means for reducing ongoing HFMD transmission in the community. Methods We analyzed neutralizing antibodies (NT) and the incidence of enterovirus (EVs) infection among household contacts of index cases in a province where HFMD remains endemic. Throat swab and 2 mL blood samples from household contacts were collected at enrollment, during and after 2 weeks follow-up. Results The incidence of EV-A71 infection among household contacts was 40/84 (47.6%, 95% Cl: 36.9-58.3%), compared with 106/336 (31.5%, 95% Cl: 26.6-36.5%) for CV-A6 and 36/107 (33.6%, 95% Cl: 24.7-42.6%) for CV-A16. The incidence of CV-A6 infection was fairly constant across ages; in contrast, CV-A71 and CV-A16 had some variation across ages. At baseline, higher geometric mean titer (GMT) of EV-A71, CV-A6, and CV-A16 antibody titers was found for 25-34-year groups (range 216.3 to 305.0) compared to the other age groups. There was a statistically significant difference in GMT values of CV-A6 and CV-A16 between those who had an infection or did not have infection among households with an index case of these serotypes. Conclusions Our results indicated that adults were becoming infected with HFMD and could be contributing to the transmission. There is, therefore, a need for considering the household setting as an additional target for intervention programs for HFMD.

Highlights

Hand, foot, and mouth disease (HFMD) is a common pediatric illness that is of public health concern in the Asia Pacific region [1]
For the 150 index cases who were clinically diagnosed with HFMD, the median age was 1.5 years (interquartile range (IQR) 0.2-5.2). 98% had fever, 85% had mouth sores, 53% had foot blisters, and 59% had hand blisters. 90/150 (60%) were reverse transcription-polymerase chain reaction (RT-PCR) positive, of which 78 cases were EVs (CV-A6 (57/78)) and 12 cases were Enterovirus A71 (EV-A71) (EV-A71 B5 (11/12))
The percentage of household contacts who were EV-A71 seropositive at baseline sample was 77.8% (424/545), while 92.5% (504/545) were coxsackievirus A6 (CV-A6) seropositive and 97.1% (529/545) were CV-A16 seropositive

Summary

Introduction

Foot, and mouth disease (HFMD) is a common pediatric illness that is of public health concern in the Asia Pacific region [1]. EV-A71 is the main causative agent of severe and death cases occurring among HFMD cases in the southern provinces in Vietnam [4, 5, 8]. Scarce information exists about immunity to hand, foot, and mouth disease (HFMD) among household contacts of index cases in Vietnam and what that means for reducing ongoing HFMD transmission in the community. We analyzed neutralizing antibodies (NT) and the incidence of enterovirus (EVs) infection among household contacts of index cases in a province where HFMD remains endemic. The incidence of EV-A71 infection among household contacts was 40/84 (47.6%, 95% Cl: 36.9-58.3%), compared with 106/336 (31.5%, 95% Cl: 26.6-36.5%) for CV-A6 and 36/107 (33.6%, 95% Cl: 24.7-42.6%) for CV-A16. Our results indicated that adults were becoming infected with HFMD and could be contributing to the transmission. There is, a need for considering the household setting as an additional target for intervention programs for HFMD

Methods

Results

Conclusion