Analysis of total antibody levels in university hospitals health workers vaccinated against COVID-19 in Abidjan (Côte d’Ivoire)

Discovered in China in December 2019, coronavirus disease-19 (COVID-19) has confronted the world with an unprecedented crisis. Healthcare workers, the first line of defense against this pandemic, have been severely affected. Clinical trial results of the emergency vaccines showed that they all produced IgG antibodies against severe acute respiratory syndrome corona virus-2 (SARS-CoV-2) with high rates of seroconversion. While immunization against natural challenge (COVID-19 infection) and artificial challenge (vaccination) in health care workers is relatively well described in the West, the issue is not well understood in Sub-Saharan Africa, particularly in Côte d’Ivoire, where populations are genetically distinct from Caucasians. Our aim was to investigate the magnitude of post-vaccination IgG responses to SARS-CoV-2 in healthcare workers in our African epigenetic context. A cross-sectional, multicenter, analytical study was conducted from March to May 2022 among health workers employed at the University Hospital of Abidjan and vaccinated against COVID-19. The study included 77 health workers. IgG immunoassays were performed with an enzyme-linked fluorescent assays. Data were analyzed using SPSS version 22.0 software, with a p-value ˂ 0.05 considered as a significant difference. All enrolled subjects developed anti-SRAS-Cov-2 IgG, of which 88.3% had a strong response (titer ≥ 250 Binding Antibody Units/ml). IgG titers varied significantly by gender (p=0.04). Vaccine type and number of doses did not affect IgG titers. However, a history of COVID-19 infection was associated with a 5-fold greater likelihood of developing a strong IgG response after vaccination. In conclusion, humoral IgG responses developed after vaccination against SARS-CoV-2 were robust and would be influenced by a variety of factors..