New Evidence on the MMR Vaccine’s Effectiveness Against COVID-19

Dr. J. Wesson Ashford, M.D., Ph.D.

In July of 2020, Dr. J. Wesson Ashford, M.D., Ph.D., shared promising information that could help senior care facilities to protect residents and staff from COVID-19. That information detailed the implementation of MMR (measles, mumps, rubella) vaccination programs within congregate care living situations. We’re pleased to share new evidence of the MMR vaccine’s effectiveness.

Understanding the MMR Vaccine

The MMR vaccine could explain disparities in how COVID-19 affects populations that differ in age and geography. Children are largely spared by the virus, while it often has severe effects on seniors.

Entire countries have also been largely spared, including Taiwan, Japan, Madagascar, and Uganda. In contrast, countries like Belgium, the United Kingdom, and the United States are experiencing significantly higher infection rates and deaths.

MMR vaccination programs implemented to help control measles in the World Health Organization Western Pacific Region included these countries which are experiencing low death rates.

Countries like Belgium, the United Kingdom, and the United States have far lower MMR vaccination rates, because measles is largely under control in these areas. Since children frequently receive two doses of the MMR vaccine between 12 and 15 months and 4 and 6 years of age, the vaccine’s effect may offer them additional protection.

Dr. Ashford explains that the evidence of the MMR vaccine’s effectiveness continues to grow. “There is even more support as the surges in the Americas and Europe are not reflected by increases in the Western Pacific Region, East Asia, or Africa. Also, there are very few children who die from COVID-19 and most children have minor illnesses, while 80% of the deaths are in individuals over 65 in the US.

“There has so far been no evidence that this not due to MMR vaccination or that there is any other possible explanation.”

The MMR vaccine is likely effective against COVID-19 because of similarities in the virus’ surface proteins. “It is likely that there are similarities between the surface proteins of the measles, mumps, and/or rubella attenuated virus particles in the MMR vaccine and those of COVID-19. By having to make antibodies to three different virus particles, the body may make antibodies which will attack COVID-19 virus particles. This mechanism would be stronger than an innate or non-specific immune mechanism.”

The Centers for Disease Control & Prevention states that the MMR vaccine is “very safe and effective.” The CDC explains that there are rare side effects, “mostly the issue is allergy to eggs. Anyone with an allergy to eggs or severe reactions to vaccinations should be cautious.” The CDC’s website has additional information on who should not get the vaccine.

New Evidence Supporting the MMR Vaccine

A new study published in the American Society for Microbiology further supports the MMR vaccine’s effectiveness in reducing COVID-19 symptom severity. The study analyzed mumps titers and COVID-19 severity levels of 80 subjects. Of those subjects, 50 would have mumps antibodies from having received the MMR II vaccine by Merck, while 30 others would have the antibodies from sources other than the vaccine, such as those naturally acquired from infections.

The study found that the group of subjects who had received the MMR vaccine and who had the highest mumps titer levels consistently had less severe symptoms. Some of those subjects were functionally immune and never tested positive for COVID-19, despite exposure. The relationship between the mumps titer levels and symptom severity did not correlate with age. Subjects who had moderate and severe symptoms had all had low titer values. This evidence suggests a relationship between COVID-19 and mumps titers.

Additional MMR Vaccine Trials

Several trials are underway to further evaluate the MMR vaccine and its potential use against COVID-19. A study based out of Cairo University Hospital in Cairo, Egypt, is studying the vaccine’s effectiveness in participants ages 18 to 50 years. The study is estimated to be completed by November 1, 2020, but results have not yet been published.

The Washington University School of Medicine in St. Louis is acting as the clinical coordinating center for an upcoming international trial. This trial is designed to evaluate the MMR vaccine’s effectiveness against SARS-CoV-2, the virus that causes COVID-19, on a large scale. It will enroll up to 30,000 international front-line health care workers. The trial will focus on health care workers from both lower- and middle-income countries, including the United States, Canada, Ireland, South Africa, Ireland, the United Kingdom, and more.

The trial stands to help keep health care workers safe. While the vaccine itself may offer protection against COVID-19, study participants will also receive education on and screening for the virus. Many of these countries have limited numbers of health care workers, and the trial could help to protect this essential population. If the trial finds additional evidence of the MMR vaccine’s effectiveness against COVID-19, it will mean that an existing vaccination that is known to be largely safe could become an important asset in protecting people and minimizing the effects of the virus.

For additional information on the latest MMR vaccine research and clinical trials, visit

Topics: Clinical , Featured Articles , Medicare/Medicaid