(ČIA) The Ministry of Health of the Czech Republic (MZ) is launching a study of collective immunity to the coronavirus. Examined will be approximately 27,000 people in four regions with a different COVID-19 burden (Prague, Brno, Olomouc and Litoměřice). A separate examination will take place in Litovel and Uničov. The study will begin on April 23. Its goal is to find out how many people recovered from COVID-19 only with little or no symptoms. The first results will be available at the beginning of May. The data will serve for decisions on further steps to reduce impacts of the pandemic.