FAMAGUSTA GAZETTE – Australian scientists have revealed that receiving a vaccine booster in the same arm as the initial dose triggers a faster and stronger immune response, potentially building protection more quickly, according to research published Tuesday.
Led by the Garvan Institute of Medical Research and the Kirby Institute at UNSW Sydney, the study—published in the journal Cell—found that nearby lymph nodes, primed by the initial dose, react more effectively when the booster is administered in the same spot. These immune hubs accelerate antibody production, especially against COVID-19 variants such as Delta and Omicron.
Clinical tests involving 30 Pfizer vaccine recipients confirmed that while both same-arm and opposite-arm groups ultimately reached similar antibody levels after four weeks, the same-arm group gained protection faster—a key advantage during pandemic outbreaks.
“This is a fundamental discovery in how the immune system organizes itself to respond better to external threats,” said Tri Phan, co-senior author and director of the Precision Immunology Program at the Garvan Institute.
Researchers emphasized that receiving boosters in different arms still leads to effective long-term protection, but during a crisis, even a few days can be critical.