THOSE who were cured of COVID-19 may only need one vaccine dose, a new study published in Science Immunology journal of Penn Institute of Immunology suggests.
The study provides more insight into the underlying immunobiology of mRNA vaccines, which could help shape future vaccine strategies.
The findings show that people who have recovered from COVID-19 had a robust antibody response after the first mRNA vaccine dose, but a little immune benefit after the second dose.
The study also suggests that only a single vaccine dose may be needed to produce a sufficient antibody response.
According to senior author and chair of Department of Systems Pharmacology and Translational Therapeutics, Penn Institute of Immunology in the Perelman School of Medicine at the University of Pennsylvania, those who did not have COVID-19 — who they called COVID naïve — did not have a full immune response until after receiving their second vaccine dose, reinforcing the importance of completing the two recommended doses for achieving strong levels of immunity.
“These results are encouraging for both short-and-long-term vaccine efficacy and this adds to our understanding of the mRNA vaccine immune response through the analysis of memory B cells. Previous COVID-19 mRNA vaccine studies on vaccinated individuals have focused on antibodies more than memory B cells. Memory B cells are a strong predictor of future antibody responses, which is why it’s vital to measure B cell responses to these vaccines. This effort to examine memory B cells is important for understanding long-term protection and the ability to respond to variants,” Wherry said.
Giving details of their effort, Wherry said they recruited 44 healthy individuals who received either the BioNTech/Pfizer or Moderna mRNA COVID-19 vaccine at the University of Pennsylvania Health System. Of this cohort, 11 had a prior COVID-19 infection. Blood samples were collected for deep immune analyses four times prior to and after vaccine doses. The data shows key differences in vaccine immune responses in COVID naïve versus COVID-19 recovered individuals.
But the findings suggest that only a single vaccine dose in individuals recovered from COVID-19 maybe enough to induce a maximal immune response, based on both strong antibody and memory B cell responses. This is likely due to a primary immune response because of their natural infection.
In contrast, it took two vaccine doses to demonstrate considerable antibody and memory B cell responses for those who did not have COVID-19, underlying the importance of the two-dose mRNA vaccine schedule to achieve optimal levels of immunity.