SARS-CoV-2 seroprevalence and implications for population immunity: Evidence from two Health and Demographic Surveillance System sites in Kenya, February-December 2022.
Kagucia, E Wangeci;
Ziraba, Abdhala K;
Nyagwange, James;
Kutima, Bernadette;
Kimani, Makobu;
Akech, Donald;
Ng'oda, Maurine;
Sigilai, Antipa;
Mugo, Daisy;
Karanja, Henry;
+28 more...Gitonga, John;
Karani, Angela;
Toroitich, Monica;
Karia, Boniface;
Otiende, Mark;
Njeri, Anne;
Aman, Rashid;
Amoth, Patrick;
Mwangangi, Mercy;
Kasera, Kadondi;
Ng'ang'a, Wangari;
Voller, Shirine;
Ochola-Oyier, Lynette I;
Bottomley, Christian;
Nyaguara, Amek;
Munywoki, Patrick K;
Bigogo, Godfrey;
Maitha, Eric;
Uyoga, Sophie;
Gallagher, Katherine E;
Etyang, Anthony O;
Barasa, Edwine;
Mwangangi, Joseph;
Bejon, Philip;
Adetifa, Ifedayo MO;
Warimwe, George M;
Scott, J Anthony G;
Agweyu, Ambrose;
(2023)
SARS-CoV-2 seroprevalence and implications for population immunity: Evidence from two Health and Demographic Surveillance System sites in Kenya, February-December 2022.
Influenza and other respiratory viruses, 17 (9).
e13173-.
ISSN 1750-2640
DOI: https://doi.org/10.1111/irv.13173
Permanent Identifier
Use this Digital Object Identifier when citing or linking to this resource.
BACKGROUND: We sought to estimate SARS-CoV-2 antibody seroprevalence within representative samples of the Kenyan population during the third year of the COVID-19 pandemic and the second year of COVID-19 vaccine use. METHODS: We conducted cross-sectional serosurveys among randomly selected, age-stratified samples of Health and Demographic Surveillance System (HDSS) residents in Kilifi and Nairobi. Anti-spike (anti-S) immunoglobulin G (IgG) serostatus was measured using a validated in-house ELISA and antibody concentrations estimated with reference to the WHO International Standard for anti-SARS-CoV-2 immunoglobulin. RESULTS: HDSS residents were sampled in February-June 2022 (Kilifi HDSS N = 852; Nairobi Urban HDSS N = 851) and in August-December 2022 (N = 850 for both sites). Population-weighted coverage for ≥1 doses of COVID-19 vaccine were 11.1% (9.1-13.2%) among Kilifi HDSS residents by November 2022 and 34.2% (30.7-37.6%) among Nairobi Urban HDSS residents by December 2022. Population-weighted anti-S IgG seroprevalence among Kilifi HDSS residents increased from 69.1% (65.8-72.3%) by May 2022 to 77.4% (74.4-80.2%) by November 2022. Within the Nairobi Urban HDSS, seroprevalence by June 2022 was 88.5% (86.1-90.6%), comparable with seroprevalence by December 2022 (92.2%; 90.2-93.9%). For both surveys, seroprevalence was significantly lower among Kilifi HDSS residents than among Nairobi Urban HDSS residents, as were antibody concentrations (p < 0.001). CONCLUSION: More than 70% of Kilifi residents and 90% of Nairobi residents were seropositive for anti-S IgG by the end of 2022. There is a potential immunity gap in rural Kenya; implementation of interventions to improve COVID-19 vaccine uptake among sub-groups at increased risk of severe COVID-19 in rural settings is recommended.
