(CNN) – Choosing the arm for your Covid-19 booster shot may impact the immune response, according to a recent study published in the journal eBioMedicine. Researchers found that receiving the booster shot in the same arm as the initial Covid-19 shot resulted in a stronger immune response.
The study, conducted by researchers from Saarland University Hospital in Germany, analyzed data from 303 individuals who received the mRNA vaccine and a booster shot as part of Germany’s vaccine campaign. Two weeks after receiving the booster, those who had both shots in the same arm showed a significantly higher number of “killer T cells” compared to those who received injections in different arms. Killer T cells are immune cells that attack and destroy targeted cells.
While the study’s findings have raised curiosity within the medical community, it is still unclear if receiving booster shots in the same arm provides better or longer-lasting protection against Covid-19. Dr. William Schaffner, a professor in the Division of Infectious Diseases at Vanderbilt University Medical Center, explains that a larger clinical study with actual infection follow-up is needed to determine the true impact.
The immune response relies on both immune cells and antibodies to fight the virus. Although the study did not find a higher number of antibodies, it did show that the antibodies from individuals who received the booster shot in the same arm were better at binding to the viral spike proteins responsible for the virus entering cells.
Despite the need for further research, Schaffner suggests considering the study results when receiving the next booster shot. He believes the findings are valuable and worth considering when deciding where to receive vaccinations for other diseases, such as respiratory syncytial virus (RSV) and influenza, along with the Covid-19 booster shot.
While the study’s sample size is small, Schaffner commends the solid laboratory assessment of the immune response. As researchers continue to explore the impact of booster shot location on immune response, individuals may contemplate whether to choose the same arm as the previous Covid-19 shots for their upcoming booster.