AUTHOR=Koech Angela , Omuse Geoffrey , Mugo Alex G. , Mwaniki Isaac G. , Mutunga Joseph M. , Mukhanya Moses W. , Wanje Onesmus , Mwashigadi Grace M. , Katana Geoffrey G. , Craik Rachel , von Dadelszen Peter , Le Doare Kirsty , Temmerman Marleen , periCOVID-Africa , The PRECISE Network , Freyne Bridget , Kawaza Kondwani , Lissauer Samantha , Sommerfelt Halvor , Etti Melanie , Musoke Philippa , Mboizi Robert , Cose Stephen , Nankabirwa Victoria , Hookham Lauren , Ouma Joseph , Rukondo Gordon , Cochet Madeleine , Voysey Merryn , Cantrell Liberty , Okiro Patricia , Juma Consolata , Ochieng Marvin , Mwadime Emily , Sevene Esperança , Tchavana Corssino , Macuacua Salesio , Vala Anifa , Boene Helena , Quimice Lazaro , Maculuve Sonia , Macete Eusebio , Mandomando Inacio , Carillho Carla , D’Alessandro Umberto , Roca Anna , Jah Hawanatu , Prentice Andrew , Martinez-Alvarez Melisa , Diallo Brahima , Sesay Abdul , Suso Sambou , Njie Baboucarr , Touray Fatima , Idris Yahaya , Kongira Fatoumata , Ndure Modou F.S. , Gabbidon Gibril , Gibba Lawrence , Bah Abdoulie , Bah Yorro , Magee Laura A. , Mistry Hiten , Volvert Marie-Laure , Mendy Thomas , Poston Lucilla , Sandall Jane , Tribe Rachel , Moore Sophie , Salisbury Tatiana T. , Russell Donna , Makanga Prestige T. , Makacha Liberty , Mlambo Reason , Papageorghiou Aris , Noble Alison , Blencowe Hannah , Filippi Veronique , Lawn Joy , Silver Matt , Waiswa Joseph , Gazeley Ursula , Cartwright Judith , Whitley Guy , Krishna Sanjeev , Vidler Marianne , Li Jing (Larry) , Bone Jeff , Kinshella Mai-Lei (Maggie) W , Tu Domena , Sandhu Ash , Pickerill Kelly , Barratt Ben TITLE=SARS-CoV-2 seroprevalence in pregnant women in Kilifi, Kenya from March 2020 to March 2022 JOURNAL=Frontiers in Public Health VOLUME=11 YEAR=2023 URL=https://www.frontiersin.org/journals/public-health/articles/10.3389/fpubh.2023.1292932 DOI=10.3389/fpubh.2023.1292932 ISSN=2296-2565 ABSTRACT=Background

Seroprevalence studies are an alternative approach to estimating the extent of transmission of SARS-CoV-2 and the evolution of the pandemic in different geographical settings. We aimed to determine the SARS-CoV-2 seroprevalence from March 2020 to March 2022 in a rural and urban setting in Kilifi County, Kenya.

Methods

We obtained representative random samples of stored serum from a pregnancy cohort study for the period March 2020 to March 2022 and tested for antibodies against the spike protein using a qualitative SARS-CoV-2 ELISA kit (Wantai, total antibodies). All positive samples were retested for anti-SARS-CoV-2 anti-nucleocapsid antibodies (Euroimmun, ELISA kits, NCP, qualitative, IgG) and anti-spike protein antibodies (Euroimmun, ELISA kits, QuantiVac; quantitative, IgG).

Results

A total of 2,495 (of 4,703 available) samples were tested. There was an overall trend of increasing seropositivity from a low of 0% [95% CI 0–0.06] in March 2020 to a high of 89.4% [95% CI 83.36–93.82] in Feb 2022. Of the Wantai test-positive samples, 59.7% (95% CI 57.06–62.34) tested positive by the Euroimmun anti-SARS-CoV-2 NCP test and 75.9% (95% CI 73.55–78.17) tested positive by the Euroimmun anti-SARS-CoV-2 QuantiVac test. No differences were observed between the urban and rural hospital but villages adjacent to the major highway traversing the study area had a higher seroprevalence.

Conclusion

Anti-SARS-CoV-2 seroprevalence rose rapidly, with most of the population exposed to SARS-CoV-2 within 23 months of the first cases. The high cumulative seroprevalence suggests greater population exposure to SARS-CoV-2 than that reported from surveillance data.