Introduction : Studying the human immune response to SARS-CoV-2 infection, as well as the factors influencing inter-individual variability in this response, is crucial to improving our understanding of the disease and guiding strategies to combat the virus. Our aim was to determine the immunological status of healthcare workers at Charles Nicolle Hospital in Tunis who had been diagnosed with SARS-CoV-2 infection, as well as the factors influencing the variability of their humoral response.

Methods : This was a retrospective and descriptive study, conducted in collaboration between the Department of Occupational Medicine and Work Capacity and the Immunology Laboratory at Charles Nicolle Hospital in Tunis. The study included healthcare workers from the same hospital who had been diagnosed with SARS- CoV-2 infection between September 2020 and March 2021 and who subsequently underwent post-infection serological testing.

Results : 551 healthcare workers were included in the study. Regardless of antibody isotype, anti-SARS-CoV- 2 seroconversion was detected in 434 healthcare workers, representing 78.7% of cases. Following multivariate analysis, the factors independently associated with seroconversion were age, the presence of symptoms like fever, anosmia and the time between symptom onset and RT-PCR diagnosis (p<10-3). Factors inversely associated with seroconversion were smoking (p = 0.002) and a history of asthma (p = 0.044).

Conclusion : Seroconversion is partial and variable among patients infected with SARS-CoV-2. Given the widespread rollout of vaccination and the continued emergence of new variants, it is important to study the kinetics of the serological profile in these patients and the level of protection against COVID-19.