A recent study led by Professor Tri Phan, further explained below, casts key new light on why vaccine injection sites are so critical. He is co-senior author and director of Garvan’s precision immunology program. Conducted with a team of scientists from the University of Michigan, the study resurrected 30 healthy adults who were vaccinated against COVID-19 with the Pfizer-BioNTech mRNA vaccine. The findings indicate that when giving both doses of the vaccine, administering them in the same arm could lead to a stronger immune response.
Professor Phan is keen to stress the significance of these findings, which will help in tailoring vaccination strategies better in the future. Here, he shows how, contrary to common understanding, vaccines enhance the proliferation of immune cells. These specialized cells are necessary for generating the antibodies required to battle infections. The researchers found that receiving a second shot in the same arm as the first better primes immune cells. This double-shot priming is designed to trigger a more powerful immune attack.
In our study, we find strong evidence supporting giving your booster dose in the same arm as your first shot. It generates neutralizing antibodies significantly quicker. Participants with second-shot administration in the opposite arm had a delayed response. This suggests that using the same arm for both doses may help the immune system respond more adeptly to potential disease outbreaks.
“What’s exciting about the research is that we showed that these other cells, called macrophages, interact with these memory B cells,” stated Professor Phan. This relationship is incredibly important. It enables the immune system to react quicker and more efficiently when re-exposed to the virus.
The work demonstrates that primed immune cells are more efficient at generating antibody responses. They play a role in helping memory B cells fine-tune their antibodies to target viral variants with maximum effect. This capacity for incalculable diversity is essential for the production of long-lasting and immunologically potent memory.
Professor Phan expressed hope that this evidence will lead to advancements in vaccination approaches, stating, “It is a fundamental discovery in how the immune system organizes itself to respond better to external threats — nature has come up with this brilliant system and we’re just now beginning to understand it.”
