The study data is from a population-based, cross-sectional survey conducted in November 2020 in Nairobi, Kenya, using multi-stage random sampling. The dataset includes serological results from 1,164 individuals tested for SARS-CoV-2 antibodies, alongside household demographic information. Adjusted seroprevalence estimates, stratified by age and population density, were linked with reported cases and deaths to calculate infection fatality ratios (IFRs), providing insights into SARS-CoV-2 transmission and its health impact in Nairobi.