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I just got the booster of the of the Pfizer-BioNTech COVID-19 vaccine this morning and I’m here to report I got the boost in the SAME arm as the prime. This tweet is not meant to serve as medical advice, but rather an explanation as to why I made this decision. Thread
I chose the same arm as this was what was recommended during the Phase 3 trials of both the Pfizer-BioNTech and Moderna mRNA vaccines. We know for these vaccines that the efficacy was 94-95%, which is awesome! I work in the influenza field, so anything above 60% is mind blowing.
If most people followed this recommendation, that clearly indicates that the antibodies being made by our immune system with this prime-boost strategy are both of high enough quantity and quality to provide protection against infection and severe disease.
I also clearly have my biases and really only thought about B cells and humoral immunity when I wrote my original tweet and completely forgot to discuss T cells! Cellular immunity (aka immunity orchestrated by T cells) are a critical component of fighting off viral infections.
Thanks to @BowyerGeorgie for sharing this awesome paper about an adenovirus vector based Ebola vaccine that utilized a prime-boost vaccination strategy with some subjects receiving the boost in the same (ipsilateral) or opposite (contralateral) arm. https://academic.oup.com/jid/article/219/8/1187/5164386
Although this study was quite different than the current vaccine regimens for the current COVID-19 vaccines (time course, vaccine platform, pathogen), this study showed that the boost in the same arm induced more functional CD4 and CD8 T cells.
I wonder if same arm boosting could better induce more functional effector and memory T cells. A boost in the same arm likely induces a larger and more persistent germinal center (GC) response. T follicular helper cells, a CD4 T cell population in GCs, produce a lot of IL-21.
Some really nice studies in the last several years have highlighted the role of CD4 T cell-derived IL-21 in regulating CD8 T cell function and memory formation. One really nice study highlighting this is from my PhD lab mate Ryan Zander at MCW. https://www.sciencedirect.com/science/article/pii/S1074761319304534?via%3Dihub
Back to B cells and the previous hypotheses I laid out – I think there needs to be further investigation into how we can optimize our immune response to enhance protection against infectious diseases.
As we try to make vaccines for some really tricky pathogens (i.e. influenza viruses, HIV, Plasmodium/malaria), one vaccine strategy likely doesn’t fit all.
I hope in future clinical trials for less pressing pathogens (you know, ones not currently causing a pandemic!), researchers will include this additional research arm of investigating the prime-boost in the same or different anatomical locations.
Vaccinology is a dynamic field and I’m excited to see how it continues to move forward. As horrible as the SARS-CoV-2 pandemic has been, it has brought to light how important it is to continue to invest in basic immunology, microbiology, and vaccinology research.
I thank the many researchers on and off twitter that continue to communicate the importance of biomedical research!
