A or B, AB or O, it doesn't matter -- your blood type has nothing to do with your risk of contracting severe COVID-19, a new study concludes. Early in the pandemic, some reports suggested people with A-type blood were more susceptible to COVID, while those with O-type blood were less so. But a review of nearly 108,000 patients in a three-state health network has found no link at all between blood type and COVID risk.