Zika virus (ZIKV) is a positive-stranded RNA virus within the Flaviviridae family. After decades of circulation in Asia, ZIKV was introduced to Brazil in 2014–2015, associated with a rise in congenital malformations. Unlike the genetically related dengue virus (DENV), ZIKV constitutes only one serotype. Although assumed that ZIKV infection may engender lifelong immunity, the long-term kinetics of ZIKV antibody responses are unclear. We assessed long-term kinetics of ZIKV NS1-IgG response in 144 individuals from 3 different subpopulations: HIV patients, tuberculosis patients and healthy individuals first tested in 2016 and retested 1.5–2 years after the 2015–2016 ZIKV epidemic in Salvador de Bahia, Brazil, using a widely distributed NS1-based commercial ELISA. The seropositivity in 2016 reached 59.0% (85/144, 95% confidence interval (CI) 50.7–66.7%), and decreased to 38.6% (56/144, CI 31.3–47.0%) 1.5–2 years later. In addition, the median ZIKV NS1-ELISA reactivity for individuals that remained positive in both timepoints significantly decreased from a ratio of 4.4 (95% CI 3.8–5.0) to 1.6 (95% CI 1.6–1.9) over the 2-year interval (Z: − 6.1; p < 0.001) irrespective of the subpopulation analyzed. Initial 2016 DENV antibody response was non-significant between groups, suggesting comparable DENV background. The high 20.6% seroreversion suggest that widely used serologic tests may fail to account a considerable proportion of past ZIKV infections in flavivirus endemic countries. In addition, ZIKV immunity might be shorter-lived than previously thought, which may contribute to local ZIKV resurgence once individual immune responses wane sufficiently to reduce community protective immunity in addition to birth and migration.

寨卡病毒（ZIKV）是黄病毒科中的一种正链RNA病毒家庭。经过数十年的亚洲流通之后，ZIKV于2014–2015年被引入巴西，这与先天畸形的增加相关。与遗传相关的登革热病毒（DENV）不同，ZIKV仅构成一种血清型。尽管假定ZIKV感染可以产生终生免疫力，但ZIKV抗体应答的长期动力学尚不清楚。我们评估了来自3个不同亚人群的144位个体的ZIKV NS1-IgG应答的长期动力学：HIV患者，结核病患者和健康个体于2016年首次接受检测，并于2015-2016年在萨尔瓦多·德巴伊亚州ZIKV流行后1.5–2年重新进行了检测，巴西，使用了广泛分布的基于NS1的商业ELISA。2016年的血清阳性率达到59.0％（85 / 144，95％置信区间（CI）50.7–66.7％），并在1.5–2年后降至38.6％（56/144，CI 31.3–47.0％）。Z：-6.1；p  <0.001），与所分析的亚人群无关。最初的2016年DENV抗体反应在各组之间无显着差异，表明DENV背景可比。血清逆转率高达20.6％，表明广泛使用的血清学检测可能无法解释黄病毒流行国家过去ZIKV感染的相当大比例。此外，ZIKV免疫力的寿命可能比以前认为的要短，一旦个体免疫反应减弱到足以降低出生和迁徙以外的社区保护性免疫力，这可能有助于局部ZIKV复活。