Background

Dengue is the most prevalent mosquito-borne viral disease and a major public health problem worldwide. Most primary infections with the four dengue virus serotypes (DENV1–4) are inapparent; nonetheless, whether the distribution of symptomatic versus inapparent infections by serotype varies remains unknown. Here, we present (1) the evaluation of a DENV1–4 envelope domain III multiplex microsphere-based assay (EDIII-MMBA) to serotype inapparent primary infections and (2) its application leveraging 17 years of prospective sample collection from the Nicaraguan Pediatric Dengue Cohort Study (PDCS).

Methods

We analysed primary DENV infections in the PDCS from 2004 to 2022 detected by inhibition ELISA (iELISA) or RT-PCR. First, we evaluated the performance of the EDIII-MMBA for serotyping with samples characterised by RT-PCR or focus reduction neutralisation test. Next, we analysed a subset of inapparent primary DENV infections in the PDCS with the EDIII-MMBA to evaluate the epidemiology of inapparent infections. Remaining infections were inferred using stochastic imputation, taking year and neighbourhood into account. Infection incidence and percentage of inapparent, symptomatic, and severe infections were analysed by serotype.

Findings

Between Aug 30, 2004, and March 10, 2022, a total of 5931 DENV-naive participants were followed in the PDCS. There were 1626 primary infections (382 symptomatic, 1244 inapparent) detected by iELISA or RT-PCR over the study period. The EDIII-MMBA demonstrated excellent overall accuracy (100%, 95% CI 95·8–100) for serotyping inapparent primary DENV infections when evaluated against gold-standard serotyping methods. Of the 1244 inapparent infections, we analysed 574 (46%) using the EDIII-MMBA. We found that the majority of primary infections were inapparent, with DENV3 exhibiting the highest likelihood of symptomatic (pooled odds ratio compared with DENV1: 2·13, 95% CI 1·28–3·56) and severe (6·75, 2·01–22·62) primary infections, whereas DENV2 was similar to DENV1 in both analyses. Considerable within-year and between-year variation in serotype distribution between symptomatic and inapparent infections and circulation of serotypes undetected in symptomatic cases were observed in multiple years.

Interpretation

Our study indicates that case surveillance skews the perceived epidemiological footprint of DENV. We reveal a more complex and intricate pattern of serotype distribution in inapparent infections. The substantial differences in infection outcomes by serotype emphasises the need for vaccines with balanced immunogenicity and efficacy across serotypes.

Funding

National Institute of Allergy and Infectious Diseases (National Institutes of Health) and Bill & Melinda Gates Foundation.

Translation

For the Spanish translation of the abstract see Supplementary Materials section.

中文翻译：

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不明显与有症状的原发性登革热病毒感染的血清型特异性流行病学模式：尼加拉瓜的一项为期 17 年的队列研究

 背景

登革热是最普遍的蚊媒病毒性疾病，也是全球主要的公共卫生问题。大多数四种登革热病毒血清型 （DENV1-4） 的原发性感染并不明显;尽管如此，按血清型划分的有症状感染与不明显感染的分布是否不同仍是未知数。在这里，我们介绍了 （1） 基于 DENV1-4 包膜结构域 III 多重微球的测定 （EDIII-MMBA） 对血清型不明显的原发感染的评估，以及 （2） 其应用利用了尼加拉瓜儿科登革热队列研究 （PDCS） 的 17 年前瞻性样本收集。

 方法

我们分析了 2004 年至 2022 年通过抑制 ELISA （iELISA） 或 RT-PCR 检测的 PDCS 中的原发性 DENV 感染。首先，我们评估了 EDIII-MMBA 对以 RT-PCR 或病灶减少中和试验为特征的样本进行血清分型的性能。接下来，我们使用 EDIII-MMBA 分析了 PDCS 中不明显的原发性 DENV 感染的子集，以评估不明显感染的流行病学。使用随机插补推断剩余的感染，同时考虑年份和邻域。按血清型分析感染发生率和不明显、有症状和严重感染的百分比。

 发现

在 2004 年 8 月 30 日至 2022 年 3 月 10 日期间，PDCS 共跟踪了 5931 名未接受过 DENV 治疗的参与者。在研究期间，通过 iELISA 或 RT-PCR 检测到 1626 例原发性感染 （382 例有症状，1244 例不明显）。当与金标准血清分型方法相比，EDIII-MMBA 对不明显的原发性 DENV 感染进行血清分型时表现出优异的总体准确性 （100%，95% CI 95·8–100）。在 1244 例不明显的感染中，我们使用 EDIII-MMBA 分析了 574 例 （46%）。我们发现大多数原发性感染是不明显的，DENV3 表现出症状性 （与 DENV1 相比的汇总比值比： 2·13， 95% CI 1·28–3·56） 和严重 （6·75， 2·01–22·62） 原发感染的可能性最高，而 DENV2 在两种分析中都与 DENV1 相似。在多年中观察到有症状和不明显感染之间的血清型分布以及有症状病例中未被发现的血清型传播的年内和年间差异很大。

 解释

我们的研究表明，病例监测扭曲了 DENV 的感知流行病学足迹。我们揭示了不明显感染中更复杂和错综复杂的血清型分布模式。不同血清型的感染结果存在巨大差异，这凸显了不同血清型之间免疫原性和有效性平衡的疫苗的必要性。

 资金

国家过敏和传染病研究所（National Institutes of Health）和比尔&梅琳达·盖茨基金会。

 译本

有关摘要的西班牙语翻译，请参阅补充材料部分。