Evidence mounts that MMR and TDAP vaccines strengthen protection against severe COVID-19https://medicalxpress.com/news/2021-08-evidence-mounts-mmr-tdap-vaccines.htmlVaccines are designed to induce a strong and long-lasting immune response through the creation of memory T cells and B cells. The Measles-Mumps-Rubella (MMR) vaccine, given during early childhood, and Tetanus-Diphtheria-Pertussis (Tdap) vaccine, given every 10 years, are known to elicit a protective response against the diseases from which the vaccines get their names. But these vaccines may have an unexpected bonus: It's possible that they also elicit cross-reactive memory T cells capable of responding to protein targets called antigens that are present in other microbes that cause diseases—including the viral antigens in SARS-CoV-2. The concept is that pre-existing memory T cells generated by prior MMR or Tdap vaccination and activated by SARS-CoV-2 infection give the immune system a head start in responding to SARS-CoV-2, thereby lowering the risk of severe COVID-19.
There has been speculation about this for quite a while. In addition to the actual vaccine active ingredients, one or both may include an adjuvant, which is a general immune system booster whose purpose is to improve the effectiveness of the vaccine's active ingredients.
It's interesting that three of the six diseases are caused by bacteria, and therefore the Tdap vaccine targets proteins created by those bacteria or are part of those bacteria. IOW, the Tdap vaccine, which has been around for quite a while, does not use traditional dead/inactivated virus vaccine technology.
