Sero-surveillance for IgG to SARS-CoV-2 at antenatal care clinics in two Kenyan referral hospitals

Lucinde, R.; Mugo, D.; Bottomley, C.; Aziza, R.; Gitonga, J.; Karanja, H.; Nyagwange, J.; Wanjiku, P.; Nzomo, E.; Tuju, J.; Kamurie, E.; Thuranira, K.; Agunda, S.; Nyutu, G. M.; Etyang, A.; Adetifa, I. M. O.; Kagucia, E.; Uyoga, S.; Otiende, M.; Otieno, E.; Ndwiga, L.; Agoti, C. N.; Aman, R.; Mwangangi, M.; Amoth, P.; Kasera, K.; Nyaguara, A.; Ng' ang'a, W.; Ochola-Oyier, L. I.; Ochola, L. B.; Barasa, E.; Bejon, P.; Tsofa, B.; Warimwe, G.; Agweyu, A.; Scott, J. A. G.; Gallagher, K. E.

The high proportion of asymptomatic and undetected SARS-CoV-2 infections presents a challenge to tracking the progress of the pandemic and implementing control measures in Kenya. We determined the prevalence of IgG to SARS-CoV-2 in residual blood samples from mothers attending antenatal care services at 2 referral hospitals in Kenya. A total of 196 samples were analysed from Kenyatta National Hospital in Nairobi in August 2020, seroprevalence, adjusted for assay sensitivity and specificity, was 49.8% (95% CI 42.0-57.8). In Kilifi County Hospital in coastal Kenya, 419 samples were analysed between September and November 2020, seroprevalence, adjusted for assay sensitivity and specificity, increased from 1.3% (95% CI 0.03-4.8) in September to 10.9% (95% CI 6.1, 16.8) in November 2020. There has been substantial, unobserved transmission of SARS-CoV-2 in parts of Nairobi and Kilifi Counties.