How the Measles Vaccine May Help Protect Against COVID-19

• Researchers say the measles, mumps, and rubella (MMR) vaccine may help protect against COVID-19.
• They came to that conclusion after their research revealed that people with higher levels of mumps antibodies tended to have less severe cases of COVID-19.
• Experts say the protection may occur because the coronavirus that causes COVID-19 acts in a similar manner to viruses that cause mumps and measles.
• However, they said it’s too early to recommend that adults get booster shots of the MMR vaccine.

COVID-19 tends to affect young children and adolescents less severely than older adults for reasons that healthcare professionals are not yet entirely clear on.

Now, some researchers say one of those reasons may lie in something children are typically given around their first birthday — the measles, mumps, and rubella (MMR) vaccine.

In a recent study published in the journal mBio, researchers concluded that people who had lower levels of antibodies for mumps in their bloodstream appeared to experience more severe cases of COVID-19, while those with higher levels of mumps antibodies had less severe cases.

To establish this link, the researchers looked specifically at titers — a test that measures levels of antibodies in the blood — for measles, mumps, and rubella.

“We found that high mumps titers (134 to 300 AU/ml) from MMR II vaccinations were found only in subjects with asymptomatic and functionally immune COVID-19 cases,” the researchers wrote. “Subjects with moderate and severe cases of COVID-19 all had low mumps titer values (below 75 AU/ml).”

“The statistically significant inverse correlation between mumps titers and COVID-19 indicates that there is a relationship involved that warrants further investigation,” said David J. Hurley, PhD, a study co-author and a professor and molecular microbiologist at the University of Georgia.

“The MMR II vaccine is considered a safe vaccine with very few side effects,” Hurley added. “If it has the ultimate benefit of preventing infection from COVID-19, preventing the spread of COVID-19, reducing the severity of it, or a combination of any or all of those, it is a very high reward low-risk ratio intervention.”

Functionally, that means as long as you have high concentrations of mumps antibody in the bloodstream, you might have some protection against COVID-19, if these study’s findings are proven accurate.

How a mumps vaccine protects

These findings might have the average person scratching their heads.

How could a vaccine that works against mumps have beneficial effects against COVID-19, a completely different virus?

The answer lies in the way the body’s immune system works, as well as the similarities between certain viruses, said Dr. Shruti Gohil, the associate medical director of epidemiology and infection prevention at UCI Health in California.

“When you’re given a vaccine, your body’s pumping out antibodies to whatever pieces and fragments of the pathogen that elicit a response from your immune system, and that allows your immune system to get educated outside of the time of infection,” Gohil told Healthline.

“And guess what? Some of those viruses — especially ones that might cause diseases in the upper respiratory tract — will have the same mechanism to make you sick with the same protein,” Gohil added. “So, if you happen to be someone who has an antibody for one face of a protein that looks like some part of COVID, that antibody could ‘cross-react’ between different pathogens.”

Vaccine schedules may make a difference 

Under a normal vaccine schedule, the age at which those antibodies fall below a level that might have a protective effect against COVID-19 appears to be around age 14, the researchers note.

“This 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,” said Dr. Jeffrey E. Gold, a lead study author and president of World Organization, in a press release. “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.”

This vaccination schedule might also explain why the United States has seen 65 percent more COVID-19 cases in infants less than 12 months of age compared with children 2 years of age, the researchers note.

“In practical terms, this is another reason for everyone to be pushing hard to ensure that MMR vaccines are administered to children throughout the world, and we already know that many families have foregone routine immunizations during the pandemic,” said Dr. Don L. Goldenberg, an emeritus professor of medicine at Tufts University School of Medicine in Boston.

What comes next 

However, Goldenberg stopped short of recommending that adults start asking for booster MMR shots.

“Administering MMR vaccine to adults to decrease illness severity during a COVID infection should not be considered until randomized clinical trials demonstrate efficacy,” he told Healthline.

Gohil concurred.

“It’s important to be thoughtful about it. I don’t think you should be giving someone a booster just because there’s a potential link,” she said.

Gohil said there haven’t been studies on giving boosters to adults, and we don’t know what side effects there might be. More research would be required before making such a recommendation.

“It would be replacing one problem for another if we didn’t study that in a systematic way,” she said.