Rapid decline of Zika virus NS1 antigen-specific antibody responses, northeastern Brazil

Virus Genes. 2020 Oct;56(5):632-637. doi: 10.1007/s11262-020-01772-2. Epub 2020 Jun 15.

Abstract

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.

Keywords: Antigens; Flavivirus; Serology; Zika virus.

Publication types

  • Observational Study

MeSH terms

  • Antibodies, Viral / blood*
  • Brazil / epidemiology
  • Comorbidity
  • Cross-Sectional Studies
  • HIV Infections / epidemiology
  • Humans
  • Immunoglobulin G / blood*
  • Prospective Studies
  • Tuberculosis / epidemiology
  • Viral Nonstructural Proteins / immunology*
  • Zika Virus / immunology*
  • Zika Virus Infection* / epidemiology
  • Zika Virus Infection* / immunology

Substances

  • Antibodies, Viral
  • Immunoglobulin G
  • NS1 protein, zika virus
  • Viral Nonstructural Proteins