Immune responses to SARS-CoV-2 in sub-Saharan Africa and western Europe: a retrospective, population-based, cross-sectional study.

Immune responses to SARS-CoV-2 in sub-Saharan Africa and western Europe: a retrospective, population-based, cross-sectional study.

Publication date: Dec 13, 2024

SARS-CoV-2 has been associated with a higher proportion of asymptomatic infections and lower mortality in sub-Saharan Africa than high-income countries. However, there is currently a lack of data on cellular immune responses to SARS-CoV-2 in people living in Africa compared with people in high-income regions of the world. We aimed to assess geographical variation in peripheral and mucosal immune responses. In this retrospective, population-based, cross-sectional study, we analysed peripheral blood and nasal curettage samples from seven clinical studies involving individuals from Senegal (Senegalese cohort), the Netherlands, and Germany (European cohort). Samples were collected between Nov 1, 2018, and Dec 20, 2021. We included samples from individuals with no, mild, or severe COVID-19. A validation cohort of individuals from Senegal and Gabon (n=64) was used to validate key findings from the main cohort. Matching of individuals between geographical regions by age, sex, viral load, and infection severity and duration was used to address confounding factors. We examined the cellular, humoral, and cytokine immune responses using cytometry by time of flight, spectral flow cytometry, ELISA, and Luminex. We included 133 individuals (59 from the Senegalese cohort and 74 from the European cohort). In contrast to the European cohort, mild COVID-19 in the Senegalese cohort was not associated with any statistically significant perturbations in blood or nasal immune cell profiles, nor with increased pro-inflammatory cytokines, although SARS-CoV-2-specific adaptive immunity was readily induced, as seen in Europeans. In severe COVID-19, both the Senegalese and European cohorts showed lymphopenia (Senegal: 2.9-times decrease, p=0.0010 vs Europe: 1.6-times decrease, p=0.0046) and increased neutrophil frequencies in blood (Senegal: 2.0-times increase, p=0.0044 vs Europe: 1.3-times increase, p=0.026) and the nasal mucosa CD66bCD16 neutrophils (Senegal: 9.9-times increase, p=0.045 vs Europe: 392-times increase, p

Concepts Keywords
133individuals Africa
Asymptomatic Blood
Germany Cohort
Viral Cov
Covid
Europe
European
Immune
Increase
Individuals
Nasal
Sars
Senegal
Senegalese
Times

Semantics

Type Source Name
disease MESH asymptomatic infections
disease IDO blood
disease MESH COVID-19
disease MESH viral load
disease MESH infection
disease IDO cell
disease MESH lymphopenia

Original Article

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