Evaluation of a rapid test against two ELISAs for a SARS-CoV-2
seroprevalence survey in Kibera informal settlement, Nairobi, Kenya
Abstract
Introduction The performance of a rapid test was evaluated
against two ELISAs as a potentially useful tool to determine exposure to
SARS-CoV-2 in low resource settings. A serosurvey was conducted in
Kibera informal settlement, Nairobi, Kenya, where low numbers of
COVID-19 were recorded during the pandemic. Materials and
methods A cross-sectional study was performed in 10 of 14 villages in
Kibera informal settlement, Kenya’s largest slum community, in August
2021, before general vaccine roll-out. Participants were age one year
and above with no symptoms of COVID-19. Capillary blood samples were
tested using the Standard Q COVID-19 IgM/IgG Combo rapid test, Platelia
SARS-CoV-2 Total Ab (IgM/IgG/IgA) Assay, and Wantai Total Ab
(IgM/IgG/IgA) ELISA for SARS-CoV-2 which served as the reference test.
Results Samples were obtained from 438 participants; in 72
samples blood was insufficient for the Platelia ELISA. Specificity of
the rapid test and Platelia ELISA were similar (>93%) but
sensitivity was low (rapid test 61.3%; Platelia ELISA 83.4%). The
Wantai ELISA showed greater positivity (82.6%) than the rapid test
(51.8%) and Platelia ELISA (69.7%). Conclusions The Wantai
ELISA showed superior performance in this serosurvey. Point-of-care
tests for convenient screening for SARS-CoV-2 exposure for surveillance
studies need to be developed.