One In Three Nairobians Has Contracted COVID-19 – Study One in three people in Nairobi has contracted coronavirus, researchers have revealed. Kenya Medical Research Institute (Kemri), Washington State University Global Health- Kenya, and the University of Nairobi came up with the findings after conducting an analysis of blood samples over the past eight months. The analysis showed that the overall seroprevalence of Covid-19 in Nairobi stood at 35 percent since the first case was reported in Kenya. Seroprevalence is the percentage of individuals in a population who have developed antibodies against an infectious agent. The study collected samples from 1,164 individuals of all ages from 527 households spread across the 17 sub-counties in Nairobi. It also revealed that at least one person had been infected with the virus in half of the households in the city.