mRNa Vaccine May Produce Long-Lasting Immunity to SARS-CoV-2
June 28, 2021
New research indicates that mRNA vaccines may produce long-lasting immunity. This morning, the medical school at Washington University of St. Louis released results from a study showing that the immune response to the Pfizer vaccine continued at high levels 15 weeks post-vaccination.
Additionally, patients vaccinated with the Pfizer and Moderna vaccines produced high levels of antibodies three weeks after their first dose, which are effectively able to neutralize three strains of the SARS-CoV-2 virus. This response was even higher in those previously infected with COVID-19 and then vaccinated.
This is the first study to show evidence of prolonged B cell production in germinal centers post-vaccination. Germinal centers are created within the lymphoid tissue and create memory B cells. The longer a germinal center remains active, the stronger the immune response will be. Once antibodies are created, they flow into the bloodstream.
The study’s researchers sampled the germinal centers in the lymph nodes of 14 vaccinated patients, three weeks after the first dose. Samples were obtained at the four, five and seven week marks as well. 10 participants gave samples 15 weeks after their first vaccine.
In the three-week sample, all 14 participants had formed germinal centers that were producing antibodies against SARS-CoV-2. This immune response peaked after the booster and decreased (yet remained detectable) at the 15 week mark.
Studies have found that antigen-specific B cells can persist for at least one year, though it should be noted that studies on the extended durability of vaccine-induced antibody responses are rare. “The persistence of S-binding germinal center B cells and plasma blasts in draining lymph nodes is a positive indicator for induction of long-lived plasma cell responses.”
“Future studies will be needed to examine whether mRNA vaccination induces a robust S-specific long-lived plasma cell compartment in the bone marrow.” It has been previously shown that a COVID-19 infection does in fact produce B cells which remain dormant in bone marrow. Further studies will elucidate the influence of a previous COVID-19 infection on germinal centers compared to vaccine-induced germinal center responses.