Prevalence of SARS-CoV-2 Antibodies in Hemodialysis Patients in Senegal: A Multicenter Cross-Sectional Study (preprint)

Background: Hemodialysis patients are among high-risk groups for COVID-19. Africa is the continent with the lowest number of cases in the general population but we have little information about the disease burden in dialysis patients. Objectives: This study aimed to describe the seroprevalence of SARS-CoV-2 antibodies in the hemodialysis population of Senegal. Patients and methods We conducted a multicenter cross-sectional survey, between June and September 2020 involving 10 public dialysis units randomly selected in eight regions of Senegal. After seeking their consent, we included 303 patients aged ≥18 years and hemodialysis for ≥3 months. Clinical symptoms and biological parameters were collected from medical records. Patients’ blood samples were tested with Abbott SARS-CoV-2 Ig G assay using an Architect system. Statistical tests were performed with STATA 20. Results: Seroprevalence of SARS-CoV-2 antibodies was 21.1% (95% CI= 16.7%-26.1%). We noticed a wide variability in SARS-CoV-2 seroprevalence between regions ranging from 5.6% to 51.7%. Among the 38 patients who underwent nasal swab testing, only six patients had a PCR-confirmed infection and all of them did seroconvert. Suggestive clinical symptoms were reported by 28.1% of seropositive patients and the majority of them presented asymptomatic disease. After multivariate analysis, a previous contact with a confirmed case and living in a high population density region were associated with the presence of SARS-CoV-2 antibodies. Conclusion: This study presents to our knowledge the first seroprevalence data in African hemodialysis patients. Compared to data from other continents, we found a higher proportion of patients with SARS-CoV-2 antibodies but a lower lethality rate.

Emergence of Novel Combinations of SARS-CoV-2 Spike Receptor Binding Domain Variants in Senegal (preprint)

The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) lineages that carry mutations in the spike gene are of concern for potential impact to treatment and prevention efforts. To monitor for new SARS-CoV-2 mutations, a panel of specimens were sequenced from both wave one (N=96), and wave two (N=117) of the pandemic in Senegal by whole genome next generation sequencing. Amongst these genomes, new combinations of SARS-CoV-2 spike mutations were identified, with E484K+N501T, L452R+N501Y, and L452M+S477N exclusively found in second wave specimens. These sequences are evidence of local diversification over the course of the pandemic and parallel evolution of escape mutations in different lineages.