# Serological evidence of concurrent Lassa virus and SARS-CoV-2 exposure in Ghana- a cross-sectional study

## TL;DR

This study found that many people in Ghana were exposed to both SARS-CoV-2 and Lassa virus, with large household sizes increasing the risk of dual exposure.

## Contribution

The study provides new serological evidence of concurrent exposure to SARS-CoV-2 and Lassa virus in Ghana and identifies household size as a risk factor.

## Key findings

- SARS-CoV-2 antibody prevalence was 64.29% and Lassa virus IgG prevalence was 20.28% in the study population.
- 20.79% of SARS-CoV-2 seropositive individuals were also seropositive for Lassa virus.
- Household size was a strong risk factor for dual exposure, with medium and large households having significantly higher odds.

## Abstract

The COVID-19 pandemic has exposed vulnerabilities in infectious disease surveillance, especially in West Africa where endemic viruses including Lassa fever persist. The overlapping clinical symptoms of these two infections create diagnostic challenges and the possibility of undetected co-infections.

A retrospective cross-sectional study was conducted using archived serum samples from a nationwide SARS-CoV-2 seroprevalence survey in Ghana. 434 samples across six regions were tested for SARS-CoV-2 total antibodies (IgG/IgM) using the WANTAI ELISA kit and Lassa virus IgG using ReLASV Pan-Lassa-NP-IgG ELISA.

SARS-CoV-2 antibody prevalence was 64.29% (n = 279) and Lassa virus IgG prevalence was 20.28% (n = 88). Of the cohort of subjects who were seropositive for SARS-CoV-2, 20.79% were also seropositive for LASV IgG. Multivariate analysis revealed household size as a strong risk factor of dual exposure. Individuals from medium-sized households (4–6 persons) (aOR = 8.78, 95% CI: 1.18–65.56, p = 0.034) and large households (≥ 7 persons) (aOR = 12.90, 95% CI: 1.99–83.40, p = 0.007) had significantly increased odds of dual seropositivity compared to small households. Regional variations were observed, with Greater Accra showing significantly lower odds of dual seropositivity (aOR = 0.13, 95% CI: 0.03–0.51, p = 0.004) compared to Ashanti Region.

This study provides serological evidence of SARS-CoV-2 and Lassa virus concurrent exposure in Ghana during the COVID-19 pandemic. This finding suggests large household size as a key driver of dual viral exposure and calls for integrated surveillance systems and targeted interventions in large household settings to reduce concurrent transmission of viruses with pandemic potential.

The online version contains supplementary material available at 10.1186/s12879-025-12385-1.