A recently released study named PROSECO, performed by the scientific centre RECETOX of the Masaryk University in conjunction with the University College London, claims that more than half of Czechs have probably contracted the covid-19 disease by now. This claim is based on data collected from a 30,000 subject sample of the Czech population, that was tested for covid-19 antibodies in their blood throughout the last year. While these people were not selected randomly, as they had to volunteer for the study, the sample size is still large enough for a claim, that more than half of Czechs have encountered the disease within their bodies, to be made. This number rose progressively. In fall of 2020, only 28% of the subjects of the study had covid-19 antibodies. However the latest tests performed in the study showed that 51% of the subjects of the study had the disease at one point. Interestingly, one third of those who ended up having antibodies never reported having any symptoms, which only goes to show how hard it is to effectively trace contacts during the covid-19 pandemic. The study is not over, as the volunteers are planned to be tested at least once again, in fall. This large study seems to be the best indicator of how covid-19 has really spread throughout our population. Thanks to it, we can determine how effective we were at detecting covid-19 cases, and use this knowledge to aid our prevention efforts in the future.