Background
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.
MethodsFrom 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.
ResultsThe 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.
ConclusionThis 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.
Key Words: SARS-CoV-2, Serosurvey, Cameroon, COVID-19