Research from Johns Hopkins University provides further evidence vaccines can provide some cross-protection against covid19. Patients who received the BCG vaccine had cross-protection against covid19; and the MMR and polio vaccines have also been shown to provide some cross-protection.
The vaccination status of seriously ill covid19 patients, patients who contracted covid19 and did not become seriously ill, and patients who did not contract covid19, is important in understanding covid19. The vaccination status of pediatric patients too young for the covid19 vaccine is particularly important, because an UTD vaccination status may provide some protection against covid19.