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Seroprevalence and Seroreversion of SARS-CoV-2 Antibodies in a Cohort of Health Care Workers, Kinshasa, Democratic Republic of Congo
19 Pages Posted: 11 Mar 2022More...
Background: Few evidence exists about the degree of seroconversion and seroreversion of SARS-CoV-2 in sub-Saharan Africa, where COVID-19 case presentation is apparently largely oligo- or asymptomatic.
Methods: A cohort of 561 health care workers from 5 health zones of Kinshasa was followed up between July 2020 and January 2021, with 6-8 weeks intervals. At each visit, information on risk exposure and a blood sample was collected. Serology was defined as positive when binding antibodies against SARS-CoV-2 spike (S) and nucleocapsid proteins (NC) were simultaneously present. Association between seropositivity and exposure-related characteristics was explored in a logistic regression analysis. Cumulative incidence for sero-conversion and -reversion was computed in a sub-cohort of 316 participants with full data over the 4 surveys.
Findings: The anti-SARS-CoV-2 antibodies seroprevalence was high, 17.3% (95%CI: 14.4-20.6), at baseline and fluctuating over time, being 10.4% (95%CI: 7.9-13.4), 15.8% (12.9-19.1) and 9% (6.6-12.0) in September/October, November 2020 and December 2020/January 2021 respectively. Seropositivity was heterogeneously distributed over the health zones (p<0.001), ranging from 12.5% (95%CI:6.6-20.8) in N’djili to 33.7% (95%CI:24.6-43.8) in Bandalungwa. In the sub-cohort over the 25 weeks, cumulative seroconversion was 10.7% and seroreversion was 84.1%, among participants that tested negative (n=253) and positive (n=63) at baseline, respectively.
Interpretation: In Kinshasa, in contrast to the reported low number of severe COVID-19 cases in the first months after the pandemic declaration, there was a high and widespread SARS-CoV-2 IgG seroprevalence among the health care workers, characterized by a frequent and rapid seroreversion in the subsequent months.
Funding: The study was funded by Enabel (the Belgian Development agency), the German Ministry for Economic Cooperation and Development (BMZ) through GIZ (its Development agency), the framework agreement between the Institute of Tropical medicine and the Belgian Development Cooperation (FA4/CREDO) and ‘Institut de Recherche pour le Développement’ (IRD).
Declaration of Interest: None to declare.
Ethical Approval: The current study was approved by the ethics committee of the University of Antwerp in Belgium (number B3002020000144) and the national ethics committee of the DRC (189/CNES/BN/PMMF/2020). Further approval was obtained from the Ministry of Health, through the provincial health division as well as the heads of concerned health zones (HZ) and health facilities.
Keywords: SARS-CoV-2, COVID-19, health care workers, Democratic Republic of Congo
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