The August pre-print study, which was published in the journal Med, found that the body’s immune response generated by memory T cells and B cells from the measles-mumps-rubella (MMR) vaccine and tetanus-diphtheria-pertussis (Tdap) vaccine, may also cross over to help fight COVID-19.
The researchers conducted lab analyses to help detect and characterize the responses of T cells, a type of white blood cell that helps protect the body from infection, to antigens.
The researchers isolated T cells from the blood of patients who had previously had COVID-19, as well as those who are vaccinated against the virus. They then applied them to antigens from SARS-CoV-2, the virus that causes COVID-19, along with the MMR and Tdap vaccines.
They also analyzed existing data and found that people who had received the MMR or Tdap vaccine had a lower risk of COVID-19 severity.
The MMR vaccine protects against measles, mumps, and rubella. Children should get two doses of the MMR vaccine, starting at 12 to 15 months old. The second dose should be given between ages four and six.
The researchers found that there was a “high correlation” between T cell responses to SARS-CoV-2 and MMR and Tdap proteins in people who had previously had COVID-19 or were vaccinated against the virus.
Those who had received the MMR or Tdap vaccine had a 32% to 38% lower risk of severe COVID-19 and 20% to 23% decreased risk, respectively.
Why Might These Vaccines Lower the Risk of Severe COVID-19?
The researchers didn’t explore this in the study, but they did theorize that there may be some cross-reactions between T cells that allow them to react to certain viruses. Having T cells that were formed after an MMR or Tdap vaccination could help prime the immune system for a potential future SARS-CoV-2 exposure.
“There has been a hypothesis that the general impact of certain childhood vaccinations extends to a broad ability of the immune system to function better,” infectious disease expert Amesh A. Adalja, MD, a senior scholar at the Johns Hopkins Center for Health Security, tells Verywell.
“Vaccines can prime the immune system in broad ways that might lead to some extra protection against COVID-19,” Richard Watkins, MD, an infectious disease physician and professor of internal medicine at the Northeast Ohio Medical University, tells Verywell.
This, Adalja says, may partially explain why most children do not develop severe complications from COVID-19.
“This is something that needs further study but it has been suggested with other infections and vaccines in the past,” he says.
Watkins points out that there has been some preliminary evidence that the flu vaccine can also be partially protective against severe COVID-19, which further strengthens this theory.
But Watkins notes that it’s “unclear” if these vaccines may have an additional protective effect alongside the COVID-19 vaccine.
So, if your child is behind on their vaccinations, now is a great time to schedule them for their routine shots.
The information in this article is current as of the date listed, which means newer information may be available when you read this. For the most recent updates on COVID-19, visit our coronavirus news page.
