MMR vaccine could protect against COVID-19

By Sarah MooreReviewed by Emily Henderson, B.Sc.Nov 20 2020

The number of reported global infections of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) stands at 56.88 million as of 19 November 2020, and this number continues to rise despite restrictions. Given that the virus is new, health systems have not been readily equipped to tackle the outbreak.

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However, a study published this month in mBio, a journal of the American Society for Microbiology, has produced evidence that supports earlier theories that an existing vaccination may protect against the more severe symptoms of SARS-CoV-2 infection.

The study's researchers found an inverse correlation between levels of mumps titers and the severity of COVID-19 disease symptoms in those who had been vaccinated with the measles-mumps-rubella MMR II vaccine.

Early hints at a link between the MMR vaccine and COVID-19 symptom severity

In September, a team at Medica Sur in Mexico City, led by Dr. Larenas-Linnemann, published the findings of their latest study, which suggested the role of the MMR vaccine in reducing symptom severity of COVID-19.

In their paper, published in the journal Allergy, the researchers explained how individuals vaccinated with the MMR vaccine since the beginning of the pandemic seemed to develop less severe symptoms than would be expected.

To follow up on this hypothesis, Jeffrey E. Gold, president of Rescue Me / World Organization, an animal shelter based in Watkinsville, GA, and a team of researchers set up a study to investigate the possible connection between the MMR vaccine and COVID-19 symptom severity.

Levels of mumps titers predict symptom severity

In the current study, 80 individuals were recruited and allocated into one of two groups, an MMR II group consisting of 50 subjects who primarily had MMR antibodies from the MMR II vaccine, and a comparison group, consisting of those with no record of MMR II vaccinations, and who would have obtained any MMR antibodies from other sources such as prior infections with measles, mumps, or rubella.

The study results showed that mumps titers and the severity of COVID-19 symptoms were significantly inversely correlated in the MMR II group. The comparison group showed no such correlation.

Within the MMR II group, those who have been functional immune of asymptomatic had the highs levels of mumps titers (134 to 300 AU/ml). As mumps titers levels reduced, COVID-19 symptoms became more pronounced. Levels of less than 134 AU/ml were found in those with mild symptoms, and those with moderate symptoms all had titers belt 75 AU/ml.

The study's lead author, Jeffrey E. Gold, highlights how the study's findings may be instrumental in developing future strategies to protect people from severe cases of COVID-19...

This [the findings] adds to other associations demonstrating that the MMR vaccine may be protective against COVID-19. It also may explain why children have a much lower COVID-19 case rate than adults, as well as a much lower death rate. The majority of children get their first MMR vaccination around 12 to 15 months of age and a second one from 4 to 6 years of age."

Further research needed to uncover the full story

In this, the first immunological study to investigate the relationship between the MMR II vaccine and symptom severity of COVID-19, scientists were able to uncover evidence to support the hypothesis that MMR II vaccinations may protect people from severe symptoms of COVID-19.

The significant inverse correlation found between mumps titers and COVID-19 symptom severity requires further research. However, given the MMR II vaccine's established safety, the results point to a possible accessible, cost-effective, and safe method for protecting people from severe symptoms of COVID-19 and even hospitalization. It is possible that MMR vaccines may provide a route to reducing preventing infection, reducing the spread of the virus, and reducing symptom severity.

However, further studies are required before a firm conclusion on the role of MMR in fighting COVID-19 can be established.

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