A person’s blood group may play a role in their risk of getting coronavirus, according to a new report. Researchers say blood group appears to modify their risk of infection and chances of developing Covid-19. Blood group O individuals’ risk of being infected by the virus are around 25% lower than someone with a non-group O blood type. Meanwhile, blood group A individuals appear to have a higher risk of infection, the ABO Blood Groups and Covid-19 report concludes. Experts say the effect of blood group on Covid-19 risk is small, particularly when compared to other risk factors where protective measures can be taken. The meta-analysis – reviewing other research on the subject – found the risks of needing intubation or of dying from the disease did not vary significantly by blood type. Professor Charles Bangham, chairman of immunology at Imperial College London and lead author of the SET-C report, said: “This sheds some light on another aspect of how the disease is caused, but it has more implications for understanding the mechanisms of infection and how we might treat it, than for prevention. “There is a small reduction in the risk of Covid-19 in people with blood group O; however, the protective effects of already recommended measures, especially social distancing, face coverings and hand-washing, are much more important for lowering our risk.” The study was conducted by the Royal Society’s SET-C (Science in Emergencies Tasking: Covid-19) group. Researchers say the mechanism of protection is unknown but may be due to the natural antibodies to blood group A and B antigens that are observed in people with blood group O. They do not identify any policy implications. According to the NHS website, blood group O is the most common, with almost half of the UK population (48%) belonging to this group. Group O blood has been shown to be protective in other diseases, including malaria, where it lowers the risk of severe forms of the disease. The report provides a rapid review of published scientific evidence on the topic and has not been through formal peer review. It concludes: “Individuals with blood group O have about two-thirds to three-quarters of the odds of acquiring Sars-CoV-2 infection of non-group O individuals, and a lower risk of Covid-19. “It is less clear whether blood group O individuals who have become infected with the virus have a lower risk of severe disease. “Blood group A is associated with significantly increased odds of Sars-CoV-2 infection, and with a greater risk of severe disease.”