Arboviral antibody biomarkers and fetomaternal outcomes in pregnant women with and without HIV across Nigeria: A multi-regional cross-sectional study.

BACKGROUND

Arboviral burden among pregnant women with HIV coinfection in sub-Saharan Africa remains inadequately characterised.

OBJECTIVES

To assess arboviral seroprevalence using IgG and IgM antibodies to distinguish historical exposure from relatively recent infection among Nigerian women.

METHODS

We conducted a cross-sectional serosurvey (December 2020-November 2023) across three Nigerian regions representing distinct ecological zones, recruiting 619 women: HIV-positive pregnant (n = 207), HIV-negative pregnant (n = 207), and HIV-positive non-pregnant (n = 205). Arboviral IgG and IgM antibodies against chikungunya virus (CHIKV), dengue virus (DENV), Zika virus (ZIKV), and other flaviviruses were detected using immunoblot assays, with plaque reduction neutralisation testing (PRNT) performed on a subset of 150 samples to support virus-specific interpretation.

RESULTS

IgG seropositivity was highest for CHIKV (42.2%), followed by DENV (27.1%) and ZIKV (13.6%). IgM seropositivity, indicating relatively recent infection, was observed for CHIKV (14.1%), DENV (9.0%), and ZIKV (4.5%). All IgM-positive individuals were also IgG-positive; overall seroprevalence patterns suggest both endemic transmission and infections occurring at different time points within a previously exposed population. Northern regions showed significantly higher odds of CHIKV IgM (aOR 2.13, 95% CI: 1.18-3.87) and ZIKV IgM (aOR 4.71, 95% CI: 1.53-14.49) seropositivity. Among pregnant women, CHIKV IgM seropositivity was associated with higher odds of preterm birth, while other birth outcome associations should be interpreted cautiously given limited power and the cross-sectional design. PRNT identified samples with predominant virus-specific neutralising patterns, while others showed evidence consistent with multiple flavivirus exposures.

CONCLUSION

Substantial arboviral exposure exists across Nigerian populations, with evidence consistent with ongoing endemic transmission. Dual serology supported by PRNT helped distinguish remote exposure from relatively recent infection, but does not precisely date infection timing. These findings support enhanced surveillance and prospective pregnancy studies incorporating molecular diagnostics (e.g., RT-PCR) to better define the impact of arboviral infection on pregnancy and birth outcomes.