Seroprevalence of SARS-CoV-2 in 10 Regional Capitals of Cameroon,
October-December 2020
Abstract
Cameroon was among the most affected African countries during the first
wave of the COVID-19 pandemic; however, the true prevalence of
SARS-CoV-2 remains unknown. From October-December 2020 we conducted a
cross-sectional, age-stratified SARS-CoV-2 seroepidemiological survey at
30 purposively selected community-based sites across Cameroon’s 10
regional capitals, sampling 10,000 individuals aged 5 years or older. We
employed a parallel SARS-CoV-2 antibody testing algorithm (WANTAI ELISA
and Abbot Architect) to improve both the positive predictive value and
negative predictive value of seroprevalence. The overall weighted and
adjusted seroprevalence of SARS-CoV-2 antibodies across the 10 urban
capitals of Cameroon was 10.5% (95% CI: 9.1%-12.0%) among
participants aged ≥5 years. Of the 9332 participants, 730 males (13.1%,
95% CI: 11.5%-14.9%) had SARS-CoV-2 antibodies compared to 293
females (8.0%, 95% CI: 6.8%—9.3%). Among those who reported a
comorbidity at the time of testing, 15.8% (95% CI: 12.8%-19.4%) were
seropositive. We estimated that over 2 million SARS-CoV-2 infections
occurred in the 10 regional capitals of Cameroon between October and
December 2020, compared to 21,160 cases officially reported at that time
translating to one laboratory-confirmed case was reported for every 110
SARS-CoV-2 infections across the 10 urban capitals. This study’s
findings point to extensive and under-reported circulation of SARS-CoV-2
in Cameroon– an almost 100-fold more cases compared to the number of
cases reported to the World Health Organization. This finding highlights
the importance of conducting serosurveys, especially in settings where
access to testing may be limited and to repeat such surveys as part of
pandemic tracking.