Use of seroprevalence to guide dengue vaccination plans for older adults in a dengue non-endemic country.

Yi-Hua Pan,Chia-Chi Ku,Hui-Ying Ko,Chwan-Chuen King,Chao-Ying Pan,Shu-Yu Lin,Yu-Wen Chien,Chin-Rur Yang,Pin-Wei Shih,Tzong-Shiann Ho,Mei-Ying Liao,Day-Yu Chao,Pei-Yun Shu,Hong-Ming Chen,Guey-Chuen Perng,Chia-Yi Yu,Shu-Fen Chang,Duane J Gubler

doi:10.1371/journal.pntd.0009312

Abstract

A shift in dengue cases toward the adult population, accompanied by an increased risk of severe cases of dengue in the elderly, has created an important emerging issue in the past decade. To understand the level of past DENV infection among older adults after a large dengue outbreak occurred in southern Taiwan in 2015, we screened 1498 and 2603 serum samples from healthy residents aged ≥ 40 years in Kaohsiung City and Tainan City, respectively, to assess the seroprevalence of anti-DENV IgG in 2016. Seropositive samples were verified to exclude cross-reaction from Japanese encephalitis virus (JEV), using DENV/JEV-NS1 indirect IgG ELISA. We further identified viral serotypes and secondary DENV infections among positive samples in the two cities. The overall age-standardized seroprevalence of DENV-IgG among participants was 25.77% in Kaohsiung and 11.40% in Tainan, and the seroprevalence was significantly higher in older age groups of both cities. Although the percentages of secondary DENV infection in Kaohsiung and Tainan were very similar (43.09% and 44.76%, respectively), DENV-1 and DENV-2 spanned a wider age range in Kaohsiung, whereas DENV-2 was dominant in Tainan. As very few studies have obtained the serostatus of DENV infection in older adults and the elderly, this study highlights the need for further investigation into antibody status, as well as the safety and efficacy of dengue vaccination in these older populations.

Highlights

Dengue, the most common arboviral disease, has expanded in recent years, with increasing numbers of outbreaks and a greater health impact worldwide, in tropical and subtropical countries [1]
Our results showed district- and city-level differences in the overall seroprevalence of anti-dengue viruses (DENV) immunoglobulin G (IgG) antibody, increased seroprevalence with age, heterogeneous distributions of DENV serotypes, and similar percentages of secondary DENV infection in both metropolises, closely matching past histories of dengue outbreaks
As clinical severity of dengue varies by DENV serotypes as well as primary or secondary DENV infection [29,30], we investigated the serostatus of each DENV serotype using a DENV NS1 serotype-specific IgG enzyme-linked immunosorbent assay (ELISA) test, which can differentiate primary versus secondary DENV infection

Summary

Introduction

The most common arboviral disease, has expanded in recent years, with increasing numbers of outbreaks and a greater health impact worldwide, in tropical and subtropical countries [1]. The incidence of DENV infections has increased thirty-fold globally over the past fifty years [5]. Travellers, at high risk of acquiring DENV infection in endemic areas, may play important roles in transmitting the virus to nonendemic regions [6,7,8,9]. Alongside the significant geographic expansion of Aedes mosquitoes and DENV infection globally, as well as an aging population, has made an increase in dengue cases among older adults in dengue non-endemic countries and areas very likely [10]. Future public health needs in these populations must be investigated in advance [11,12]

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Results

Discussion

Conclusion