WASHINGTON — As the world awaits the approval of experimental COVID-19 vaccines, researchers are finding more proof an existing vaccine can reduce the severity of the virus. The measles-mumps-rubella (MMR) vaccine has been previously linked to better protection against coronavirus. Now, a release from the American Society for Microbiology reveals the amount of Immunoglobulin G (IgG) mumps antibodies in the body directly ties to how sick a COVID-19 patient gets.
The study finds the more of these mumps IgG titers a person vaccinated with MMR II has, the weaker their case of COVID ended up being. The MMR II vaccine contains strains of all three of those illnesses. Children typically receive two shots, a year after birth and again during childhood.
“We found a statistically significant inverse correlation between mumps titer levels and COVID-19 severity in people under age 42 who have had MMR II vaccinations,” lead study author Jeffrey E. Gold says in a media release. “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. 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.”
MMR vaccination may help you beat the pandemic
Researchers examined 80 participants split into two distinct groups. The first included 50 Americans who obtained most of their MMR antibodies through the MMR II vaccine. The other 30 participants had no record of ever receiving the vaccination. This means they would have only gained MMR antibodies from prior infections of measles, mumps, or rubella.
For the vaccinated patients, the results show a clear connection between mumps titers and the severity of COVID-19 symptoms. For the 30 unvaccinated people however, the study finds no connection between their antibody levels and the strength of infection.
The team did not find a connection between mumps titers and the age of people in the MMR II group. Measles and rubella titers don’t seem to have a link to COVID severity either, only antibodies to the mumps.
The more you’re protected against mumps, the better it is for surviving COVID
In the vaccinated group, researchers say patients with mumps titers measuring between 134 to 300 AU/ml were asymptomatic or even functionally immune to coronavirus. Participants with mild cases of the virus had mumps titers under 134 AU/ml. When those readings drop below 75 AU/ml, patients developed moderate symptoms of COVID-19. Any participant who had levels falling under 32 AU/ml ended up in the hospital and on oxygen.
“This is the first immunological study to evaluate the relationship between the MMR II vaccine and COVID-19. The statistically significant inverse correlation between mumps titers and COVID-19 indicates that there is a relationship involved that warrants further investigation,” says co-author David J. Hurley, a molecular microbiologist at the University of Georgia.
“The MMR II vaccine is considered a safe vaccine with very few side effects. 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. Maximum seropositivity is achieved through two vaccinations at least 28 days apart. Based upon our study, it would be prudent to vaccinate those over 40 regardless of whether or not they already have high serum MMR titers.”
The study appears in the journal mBio.