Emergency medicine journal : EMJ
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Meta Analysis
Best Evidence Topic report: does blood group type O decrease the risk of severe COVID-19 infection?
A short-cut systematic review was conducted using a described protocol. The three-part question addressed was: In patients with COVID-19 infection, does blood group type O versus non-O blood groups lead to a lower risk of severe COVID-19 infection? MEDLINE, Embase, and Cochrane databases were searched for relevant evidence. Altogether, 238 papers were found using the search strategy developed. ⋯ Finally, 4 out of 17 studies revealed that having blood group type O may be associated with a lower risk of severe COVID-19 among patients with COVID-19 infection and the 13 remaining studies reported no significant relationship between having O blood group and risk of COVID-19 severity among the infected individuals. Of three systematic reviews and meta-analyses identified, none detected a protective effect of blood group type O. The clinical bottom line is that the best available evidence does not support the notion that blood group type O is protective against serious outcomes in COVID-19.