Researchers from the Emory University Centers of Excellence for Influenza Research and Response (Emory-CEIRR) and SAVE, including the laboratories of Dr. Jens Wrammert, Dr. Rafi Ahmed, and Dr. Mehul Suthar, characterize the immune response in naïve and recovered individuals following SARS-CoV-2 vaccination with either the Moderna or Pfizer-BioNTech mRNA vaccines.
Although mRNA vaccines have only recently become available to the public, they have been studied for decades. There are two SARS-CoV-2 mRNA vaccines currently approved by the FDA, created by Pfizer-BioNTech and Moderna. Both vaccines are approved for use in individuals at least 6 months old and involve a two dose primary vaccination series for those 5 years and older. Due to the recent emergence of SARS-CoV-2, our understanding of the immune landscape that results from the administration of these vaccines is still lacking. Therefore, thorough characterization of individual vaccine-induced immune responses is pivotal for long-term vaccination strategies.
A recently published article by Grace Mantus and colleagues in Cell Reports Medicine investigated the breadth and longevity of the humoral immune response, a type of adaptive immunity that is largely mediated by secreted antibodies, following a SARS-CoV-2 mRNA vaccination. Their study compared the immunity exhibited in people who had either never been infected with SARS-CoV-2 or had a known infection and had since recovered at the time of sampling. The authors characterized the type of antibodies and antibody-producing immune cell populations that are generated after mRNA vaccination. Then Mantus et al. investigated how the post-vaccination responses compared depending on whether an individual had or had not been infected with SARS-CoV-2 previously.
Their findings suggest mRNA vaccination without prior infection drives memory B-cell responses, a long lasting adaptive immune cell that can rapidly drive antibody production to prior infections, and leads to antibody responses equal to or greater than infection alone. Furthermore, they found that individuals who have had SARS-CoV-2 infections and recovered prior to vaccination developed a robust immune response after the first mRNA vaccine dose. In contrast, naïve individual immune responses peaked about one-to-two weeks after the second dose. These results suggest a single vaccine dose may sufficiently protect individuals with previous SARS-CoV-2 infections. Importantly, both mRNA vaccines showed similar effectiveness in driving immune expansion and virus neutralizing activity. Taken together, the results highlight the differences of the immune response following SARS-CoV-2 mRNA vaccination that are dependent upon prior infection history. This issue will only become more complex as global virus circulation continues and new variants arise. Studies such as this one provide vital information that can aid in the development of future vaccine guidance.