Seroprevalence and molecular detection of SARS-CoV-2 among apparently healthy healthcare workers and patients in a Nigerian tertiary hospital.

BACKGROUND

SARS-CoV-2 continues to drive community and healthcare-associated transmission globally, with limited data from sub-Saharan Africa on asymptomatic carriage and infection dynamics. We conducted a dual serological and molecular study to determine the prevalence of past and current SARS-CoV-2 infections among apparently healthy healthcare workers (HCWs) and patients in a Nigerian tertiary hospital.

METHODS

We performed a cross-sectional study at the Federal Teaching Hospital, Gombe, Nigeria, enrolling 250 participants (35 HCWs and 215 patients). Venous blood samples were tested for anti-SARS-CoV-2 IgM/IgG antibodies using validated rapid diagnostic tests, while nasopharyngeal/oropharyngeal swabs were analysed by real-time reverse transcription polymerase chain reaction (qRT-PCR) targeting SARS-CoV-2 genes. Socio-demographic and behavioural data were collected via structured questionnaires. Data were analysed using descriptive statistics and chi-square tests, with significance set at p < 0.05.

RESULTS

Overall, 42.0% (n = 105) of participants were seropositive for SARS-CoV-2 antibodies, predominantly IgG (41.6%), with minimal IgM detection (0.4%). Antibody prevalence was significantly higher among patients (37.6%) than HCWs (4.0%) (p < 0.001). SARS-CoV-2 RNA was detected in 42.8% (n = 107) of participants, all of whom were patients. No HCWs tested positive for active infection. All qRT-PCR–positive cases were also IgG positive, suggesting late-phase or resolving infections. Risk factor analysis revealed no statistically significant associations between infection and comorbidities such as hypertension, diabetes, or asthma (p > 0.05).

CONCLUSIONS

This study demonstrates substantial community transmission of SARS-CoV-2 among apparently healthy patients in a Nigerian tertiary hospital, contrasted with the absence of active infection among HCWs, which may reflect effective IPC practices, although other unmeasured factors could also contribute. The combined use of serology and molecular testing provided complementary insights into both past exposure and ongoing infections. Our findings highlight the importance of dual diagnostic strategies for surveillance in high-risk healthcare settings and reinforce the need for sustained IPC measures, alongside strengthened community-level interventions, to mitigate COVID-19 transmission in Nigeria. CLINICAL TRIAL: Not applicable.