EFFICACY OF THE MEASLES-MUMPS-RUBELLA (MMR) VACCINE IN THE REDUCING THE SEVERITY OF COVID-19: AN INTERIM ANALYSIS OF A RANDOMISED CONTROLLED CLINICAL TRIAL
Background: COVID–19 is still a challenge, both with regard to its treatment and to the actual efficacy of the vaccines available to date, especially with the emergence of new variants. We evaluated the efficacy of the measles–mumps–rubella (MMR) vaccine in preventing SARS–CoV–2 infection and severity of COVID–19 in health workers. Methods: This analysis includes data from one ongoing blinded, randomized, placebo–controlled trial with participants aged 18–60 years were randomly assigned to receive the MMR vaccine or a placebo. The primary efficacy analysis included all participants with a positive nasopharyngeal RT–PCR test since their inclusion. Results: The MMR vaccine did not prevent the SARS–CoV–2 infection. Participants in the MMR group, compared with those in the placebo group, had a 48% risk reduction in symptomatic COVID–19 (RR = 0.52; 95% CI: 0.33-0.83; p=0.004) and a 76% risk reduction in COVID–19 treatment (RR = 0.24; 95% CI: 0.06-0.88; p = 0.020) with one dose and a 51% risk reduction in COVID–19 symptoms (RR = 0.49; 95% CI: 0.31 – 0.78; p = 0.001) and a 78% risk reduction in COVID–19 treatment (RR = 0.22; 95% CI: 0.06-0.82; p = 0.015) with two doses. Conclusions: This interim analysis of an ongoing clinical trial suggests that compared with a placebo, the vaccine reduces the risk of COVID–19 symptoms and reduces the need for COVID–19 treatment.