Can a Measles Vaccine (or MMR) booster reduce the risk of COVID-19?
The simple answer is: we don’t know, but many scientists are calling for further research.
Typically a childhood vaccine series, the measles-mumps-rubella (MMR) vaccine is also recommended as a one-time adult booster for high-risk patients such as healthcare workers. Recently some scientists have proposed studying whether an adult booster of this live virus vaccine might generally ramp up immunity, preventing some of the most severe effects of COVID-19. The thinking is that because the MMR vaccine uses highly weakened, or attenuated, versions of the measles, mumps and rubella viruses to produce immune protection without making people sick, the use of these “live” viruses might stimulate an immune response that is broad and goes beyond the production of antibodies. “There is mounting evidence that live attenuated vaccines provide nonspecific protection against lethal infections unrelated to the target pathogen of the vaccine by inducing ‘trained’ nonspecific innate immune cells for improved host responses against subsequent infections,” Paul Fidel of Louisiana State University and Mairi Noverr of Tulane University wrote in a letter to the journal mBio.
Supporting this concept for COVID-19 risk reduction, it was recently postulated that the milder symptoms (and only one hospitalization) in the 955 sailors on the USS Roosevelt who tested positive for COVID-19 could be due to the fact that all US Navy recruits receive adult MMR booster vaccines. Additionally, epidemiological data suggests a correlation between geographical locations where MMR vaccine is commonly available and reduced COVID-19 death rates.
While this has not yet been studied for its effect on COVID-19, there are only a few contraindications for administering a live attenuated vaccine like MMR to adults, including if the patient is immunocompromised, pregnant, or has shown previous allergic responses to the vaccination.