Sustained chronic inflammation and altered childhood vaccine responses in children exposed to Zika virus.

Background: Congenital Zika virus (ZIKV) infection leads to severe newborn abnormalities, but its long-term impact on childhood immunity is not well understood. This study aims to investigate the serum proteomics in children exposed to ZIKV during pregnancy to understand potential immunological consequences during early childhood.

Methods: The study included ZIKV-exposed infants (ZEI) at birth (n = 42) and children exposed to ZIKV (ZEC) at two years of age (n = 20) exposed to ZIKV during pregnancy, as well as healthy controls. Serum proteomic analysis was performed on these groups to assess inflammation and immune profiles. Additionally, antibody titres against two common childhood vaccines, DTaP and MMR, were measured in healthy controls (n = 50) and ZEC (n = 92) to evaluate vaccine-induced immunity.

Findings: Results showed elevated inflammation in ZEI with birth abnormalities. Among ZEC, despite most having normal clinical outcomes at two years, their serum proteomics indicated a bias towards Th1-mediated immune responses. Notably, ZEC displayed reduced anti-Diphtheria toxin and anti-Clostridium tetani IgG levels against DTaP and MMR vaccines. They also exhibited lower antibody titres particularly against Th2-biased DTaP vaccines, but not Th1-biased MMR vaccines.

Interpretation: In conclusion, the study highlights the long-term immunological consequences of congenital ZIKV exposure. Heightened inflammation was observed in ZEI with abnormalities at birth, while ZEC maintained a chronic Th1-biased immune profile. The impaired response to Th2-biased vaccines raises concerns about lasting effects of ZIKV exposure on immune responses. Consequently, there is a need for continued longitudinal clinical monitoring to identify potential immune-related complications arising from prenatal exposure to ZIKV.

Funding: This work was partially funded by the National Institute of Allergy and Infectious Diseases (NIAID) and National Institute of Dental and Craniofacial Research (NIDCR).