A study investigating the theoretical protection of the measles-mumps-rubella (MMR) vaccine against COVID-19 revealed that there is a significant inverse correlation between mumps titres from MMR vaccine (MMR II) and COVID-19 severity, according to an article published in mBio, the open access journal published by the American Society for Microbiology and the American Academy of Microbiology.
The researchers divided 80 subjects into two groups, comparing MMR titres to recent COVID-19 severity levels. The MMR II group consisted of 50 subjects who would primarily have MMR antibodies from the MMR II vaccine and the comparison group consisted of 30 subjects who would primarily have MMR antibodies from other sources, including prior measles, mumps and/or rubella illnesses.
The results show that there was a significant inverse correlation between mumps virus titres and COVID-19 severity within the MMR II group. There was also a significant inverse correlation between symptom scores and mumps IgG titres. These correlations were not significant in the comparison group.
Neither group showed significant correlations between severity and measles or rubella titres. There were also no significant correlations between age and severity or between age and symptom scores in either group.
These findings support the theorised association between the MMR vaccine and COVID-19 severity, the authors conclude.