High Zika Virus Seroprevalence in Salvador, Northeastern Brazil Limits the Potential for Further Outbreaks.
High Zika Virus Seroprevalence in Salvador, Northeastern Brazil Limits the Potential for Further Outbreaks.
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DOI：
10.1128/mbio.01390-17
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发表时间：
2017-11-14
期刊：
影响因子：
6.4
通讯作者：
Drexler JF
中科院分区：
文献类型：
--
作者：
Netto EM;Moreira-Soto A;Pedroso C;Höser C;Funk S;Kucharski AJ;Rockstroh A;Kümmerer BM;Sampaio GS;Luz E;Vaz SN;Dias JP;Bastos FA;Cabral R;Kistemann T;Ulbert S;de Lamballerie X;Jaenisch T;Brady OJ;Drosten C;Sarno M;Brites C;Drexler JF
2015 年至 2016 年期间，巴西报告的寨卡病毒 (ZIKV) 病例比任何其他国家都多，但人口暴露情况仍不清楚。 ZIKV 的血清学研究受到针对异源病毒的交叉反应性免疫反应的阻碍。我们使用酶联免疫吸附测定 (ELISA) 和噬斑减少技术，对 2015 年至 2016 年期间前瞻性采样的 633 名个体进行了寨卡病毒、登革热病毒 (DENV) 和基孔肯雅病毒 (CHIKV) 血清调查，其中包括小头畸形和非小头畸形妊娠、艾滋病毒感染者、结核病患者以及巴西东北部萨尔瓦多的大学工作人员中和试验。使用 2013 年至 2015 年期间从 277 名 HIV 感染者身上回顾性采集的血清样本来评估 ZIKV 随着时间的推移的传播情况。对个体进行地理参考，并对 ZIKV 阳性和阴性区域以及有和没有小头畸形病例的区域之间的社会人口统计学指标进行比较。流行病学关键参数在贝叶斯框架中建模。 ZIKV 血清阳性率在 2015 年至 2016 年期间迅速上升，到 2016 年达到 63.3%（95% 置信区间 [CI]，59.4% 至 66.8%），与 DENV 血清阳性率（75.7%；CI，69.4% 至 81.1%）相当，并高于 CHIKV 血清阳性率（7.4%；CI，5.6）至 9.8%）。在 19 例小头畸形妊娠中，94.7% 显示出 ZIKV IgG 抗体，而在 257 例非小头畸形妊娠中，这一比例为 69.3% (P = 0.017)。社会人口统计数据分析显示，低社会经济地位 (SES) 地区的 ZIKV 负担较高。高血清流行率，结合病例数据动态，可以估计疫情爆发时的基本传染数 R0 为 2.1（CI，1.8 至 2.5），并且随后几年的有效传染数 Reff <1。我们的数据证实了与 ZIKV 相关的先天性疾病以及低 SES 和 ZIKV 感染之间的关联，并表明群体免疫导致了疫情的停止。需要在其他地区进行类似的研究来确定美国寨卡病毒爆发的命运。正在发生的美国寨卡病毒（ZIKV）疫情涉及数百万病例，对孕产妇和儿童健康产生重大影响。了解感染率对于预测未来的流行模式和确定孕产妇在怀孕期间感染 ZIKV 后发生小头畸形的绝对风险至关重要。由于未知原因，绝大多数寨卡病毒相关小头畸形病例集中在巴西东北部。我们分析了萨尔瓦多的不同亚群，萨尔瓦多是巴西大都市，是美国寨卡病毒爆发期间受影响最严重的地区之一。我们证明寨卡病毒在巴西萨尔瓦多迅速传播，感染率超过 60%。我们提供了寨卡病毒与小头畸形之间联系的证据，报告寨卡病毒主要影响社会经济地位较低的地理区域，并表明人群免疫力可能导致疫情停止。我们的结果使利益相关者能够确定疫苗接种和疫苗功效试验的目标人群，并重新调整研究工作和干预策略的重点。
During 2015 to 2016, Brazil reported more Zika virus (ZIKV) cases than any other country, yet population exposure remains unknown. Serological studies of ZIKV are hampered by cross-reactive immune responses against heterologous viruses. We conducted serosurveys for ZIKV, dengue virus (DENV), and Chikungunya virus (CHIKV) in 633 individuals prospectively sampled during 2015 to 2016, including microcephaly and non-microcephaly pregnancies, HIV-infected patients, tuberculosis patients, and university staff in Salvador in northeastern Brazil using enzyme-linked immunosorbent assays (ELISAs) and plaque reduction neutralization tests. Sera sampled retrospectively during 2013 to 2015 from 277 HIV-infected patients were used to assess the spread of ZIKV over time. Individuals were georeferenced, and sociodemographic indicators were compared between ZIKV-positive and -negative areas and areas with and without microcephaly cases. Epidemiological key parameters were modeled in a Bayesian framework. ZIKV seroprevalence increased rapidly during 2015 to 2016, reaching 63.3% by 2016 (95% confidence interval [CI], 59.4 to 66.8%), comparable to the seroprevalence of DENV (75.7%; CI, 69.4 to 81.1%) and higher than that of CHIKV (7.4%; CI, 5.6 to 9.8%). Of 19 microcephaly pregnancies, 94.7% showed ZIKV IgG antibodies, compared to 69.3% of 257 non-microcephaly pregnancies (P = 0.017). Analyses of sociodemographic data revealed a higher ZIKV burden in low socioeconomic status (SES) areas. High seroprevalence, combined with case data dynamics allowed estimates of the basic reproduction number R0 of 2.1 (CI, 1.8 to 2.5) at the onset of the outbreak and an effective reproductive number Reff of <1 in subsequent years. Our data corroborate ZIKV-associated congenital disease and an association of low SES and ZIKV infection and suggest that population immunity caused cessation of the outbreak. Similar studies from other areas will be required to determine the fate of the American ZIKV outbreak. The ongoing American Zika virus (ZIKV) outbreak involves millions of cases and has a major impact on maternal and child health. Knowledge of infection rates is crucial to project future epidemic patterns and determine the absolute risk of microcephaly upon maternal ZIKV infection during pregnancy. For unknown reasons, the vast majority of ZIKV-associated microcephaly cases are concentrated in northeastern Brazil. We analyzed different subpopulations from Salvador, a Brazilian metropolis representing one of the most affected areas during the American ZIKV outbreak. We demonstrate rapid spread of ZIKV in Salvador, Brazil, and infection rates exceeding 60%. We provide evidence for the link between ZIKV and microcephaly, report that ZIKV predominantly affects geographic areas with low socioeconomic status, and show that population immunity likely caused cessation of the outbreak. Our results enable stakeholders to identify target populations for vaccination and for trials on vaccine efficacy and allow refocusing of research efforts and intervention strategies.