Unconfirmed claim about the coronavirus, part of the pro-Kremlin disinformation campaign around the pandemic. Only one study, which has not been peer-reviewed, has found any evidence of this claim - researchers studying COVID-19 in Wuhan and the city of Shenzhen found the proportion of blood type A patients both infected and killed by the disease was “significantly” higher. However, the authors cautioned that these preliminary findings should not be used to guide clinical practice and came with several caveats. First, the study is a draft of a research paper that has not yet been peer-reviewed or published in any journal. Second, the study is limited in both sample size and geographic scope. Speaking to the South China Morning Post, Gao Yingdai, a Tianjin-based researcher not involved in the study, said that while a 2,000-person sample is not necessarily small, it is dwarfed by the number of cases globally. While evidence does support the hypothesis that COVID-19 — or other infections — can affect people differently depending on their blood type, such a conclusion about COVID-19 cannot be made conclusively on the basis of a single study that has yet to be peer-reviewed or published in a journal. Read further debunking by Snopes. For other disinformation cases about the coronavirus, see here.