Nov. 20 (UPI) -- The measles, mumps and rubella vaccine appears to offer at least some protection against COVID-19, possibly preventing severe illness from the disease, a study published Friday by the online journal mBio found.
Among 41 people born in the United States who received the shot -- known as the MMR vaccine -- eight had immunity against the new coronavirus or had no symptoms after becoming infected, the researchers said.
This apparent immunity against severe COVID-19 may have been because of their high levels of antibodies -- or immune cells that fight off infection -- against the mumps, they said.
Seventeen people who received the MMR vaccine but had lower mumps antibody levels developed only mild COVID-19 symptoms, while those with the fewest mumps antibodies after vaccination suffered moderate illness or needed to be hospitalized for treatment.
"This adds to other associations demonstrating that the MMR vaccine may be protective against COVID-19," study co-author Dr. Jeffrey E. Gold said in a statement.
"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 Gold, who is president of Watkinsville, Georgia-based World Organization, which led the research.
More than 95% of all children in the United States receive their first MMR vaccination at 12 to 15 months old and a second shot between the ages of 4 and 6 years, according to the Centers for Disease Control and Prevention, which strongly recommends the shot.
Although more than 250,000 Americans have died from COVID-19 since the start of the pandemic, fewer than 100 of these deaths have involved children aged 14 years and younger, the agency estimates.
The mBio study published Friday is not the first to find potential benefits for the MMR vaccine against the new coronavirus.
A study published in September by the journal Allergy found that 36 of 255 people who received the MMR vaccine developed COVID-19, and all had mild forms of the disease.
For this study, Gold and his colleagues monitored 50 people who have received the MMR vaccine and were tested for COVID-19, and compared their rate of new coronavirus infection to 30 people who had not had the shot.
Five study participants who had the lowest mumps antibody levels after MMR vaccination required hospitalization and supplemental oxygen to treat their COVID-19.
Twenty-eight study participants who had higher mumps antibody levels developed "moderate" or "mild" COVID-19, and eight with the highest antibody levels were found to be "functionally immune," or have completely asymptomatic COVID-19.
"The ... inverse correlation between mumps [antibody levels] and COVID-19 indicates that there is a relationship involved that warrants further investigation," study co-author David J. Hurley said in a statement.
"If [the MMR vaccine] 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," said Hurley, a professor and molecular microbiologist at the University of Georgia.