CNN – People with blood type O may be less vulnerable to Covid-19 and have a reduced likelihood of getting severely ill, according to two studies published Wednesday. Experts say more research is needed.

A phlebotomist wearing protective gloves draws blood from a patient for a Covid-19 antibody test at a GUARDaHEART Foundation testing site in Los Angeles, California, U.S., on Wednesday, Aug. 5, 2020. California reported 202 new virus deaths, marking its second-deadliest day of the pandemic. The state has had 9,703 Covid fatalities. Photographer: Patrick T. Fallon/Bloomberg