Seroprevalence of SARS-CoV-2 Antibodies in Unvaccinated Malian Medical Students

Overview

This cross-sectional study assessed SARS-CoV-2 antibody seroprevalence among 300 unvaccinated medical students in Bamako, Mali, stratified by hospital exposure level. Results highlight high seroprevalence rates, particularly among students with greater clinical exposure, suggesting substantial natural immunity in this population.

Background

COVID-19 emerged in late 2019 and spread globally, with Africa initially predicted to become a major epicenter but experiencing relatively fewer cases. Mali reported its first cases in March 2020 and implemented control measures including vaccination starting in March 2021. Medical students, who share clinical environments with healthcare workers, represent a key group for assessing infection risk and immunity, yet their serostatus has been understudied. Understanding their antibody prevalence can inform vaccination strategies and academic policies regarding clinical rotations.

Data Highlights

Key Findings

• Overall seroprevalence of anti–SARS-CoV-2 antibodies was assessed among 300 unvaccinated medical students.
• Students were stratified into three groups by hospital exposure: first-year (low), externs (moderate), and interns (high).
• Serological testing included detection of IgA, IgM, and IgG antibodies using a rapid diagnostic test with high sensitivity and specificity after two weeks of infection.
• A surrogate neutralization assay was performed to evaluate functional neutralizing antibody responses.
• Clinical rotations and hospital internships continued despite university closures, maintaining exposure risk.

Clinical Implications

High seroprevalence among medical students, especially those with clinical exposure, indicates significant natural immunity which may influence vaccination prioritization and timing. These findings support the safe continuation of in-person clinical training with appropriate infection control measures. Monitoring antibody status in this population can guide institutional policies to balance educational needs and infection risk.

Conclusion

The study demonstrates substantial SARS-CoV-2 antibody prevalence among unvaccinated medical students in Bamako, correlating with hospital exposure levels. This natural immunity data is vital for informing vaccination strategies and academic decisions in Mali's medical education context.

References

1. WHO and Mali Ministry of Health Reports 2020-2022 -- COVID-19 Epidemiology and Vaccination in Mali
2. Immuno-Biological Laboratories, USA -- SARS-CoV-2 Antibody Rapid Diagnostic Test Instructions
3. Boditech, Republic of Korea -- ichromax COVID-19 Neutralization Assay Package Insert