Etyang AO
Adetifa I
Omore R
Misore T
Ziraba AK
Ng'oda MA
Gitau E
Gitonga J
Mugo D
Kutima B
Karanja H
Toroitich M
Nyagwange J
Tuju J
Wanjiku P
Aman R
Amoth P
Mwangangi M
Kasera K
Ng'ang'a W
Akech D
Sigilai A
Karia B
Karani A
Voller S
Agoti CN
Ochola-Oyier LI
Otiende M
Bottomley C
Nyaguara A
Uyoga S
Gallagher K
Kagucia EW
Onyango D
Tsofa B
Mwangangi J
Maitha E
Barasa E
Bejon P
Warimwe GM
Scott JAG
Agweyu A
PLOS Glob Public Health. 2022;2e0000883
BACKGROUND: Most of the studies that have informed the public health response to the COVID-19 pandemic in Kenya have relied on samples that are not representative of the general population. We conducted population-based serosurveys at three Health and Demographic Surveillance Systems (HDSSs) to determine the cumulative incidence of infection with SARS-CoV-2. METHODS: We selected random age-stratified population-based samples at HDSSs in Kisumu, Nairobi and Kilifi, in Kenya. Blood samples were collected from participants between 01 Dec 2020 and 27 May 2021. No participant had received a COVID-19 vaccine. We tested for IgG antibodies to SARS-CoV-2 spike protein using ELISA. Locally-validated assay sensitivity and specificity were 93% (95% CI 88-96%) and 99% (95% CI 98-99.5%), respectively. We adjusted prevalence estimates using classical methods and Bayesian modelling to account for the sampling scheme and assay performance. RESULTS: We recruited 2,559 individuals from the three HDSS sites, median age (IQR) 27 (10-78) years and 52% were female. Seroprevalence at all three sites rose steadily during the study period. In Kisumu, Nairobi and Kilifi, seroprevalences (95% CI) at the beginning of the study were 36.0% (28.2-44.4%), 32.4% (23.1-42.4%), and 14.5% (9.1-21%), and respectively; at the end they were 42.0% (34.7-50.0%), 50.2% (39.7-61.1%), and 24.7% (17.5-32.6%), respectively. Seroprevalence was substantially lower among children (<16 years) than among adults at all three sites (p
