Two separate studies, published Thursday in the journals Science and Science Immunology, found that the highly contagious and potentially fatal measles virus can cause “immune amnesia,” removing antibodies that had protected patients from other illnesses.

Researchers from the Harvard Medical School, who led the Science study, examined blood samples from children before and after getting measles. They found that the virus wipes out 11% to 73% of patients’ protective antibodies, putting them at greater risk of viral and bacterial strains they were previously immune to.