Germany: A new study, published in the journal eBioMedicine, has suggested that the immune response may be stronger if your booster goes in the same arm as your last COVID-19 shot.
“The question seems so banal and trivial that nobody before has thought to ask it,” study co-author Ms. Martina Sester, a biologist and head of the department of the Institute of Infection Medicine at Saarland University Hospital in Germany, said in a news release.
The study used the data of 303 people who received the mRNA vaccine and a booster shot as part of Germany’s vaccine campaign.
“Two weeks after the booster, the number of “killer T cells” was significantly higher in those who had both shots in the same arm,” the study found.
According to study co-author Ms. Laura Ziegler, a doctoral student at Saarland University, those cells, which attack and destroy the other cells they target, were present in 67 percent of the same-arm cases and only 43 percent of people who had their injections in different arms.
“It is absolutely fascinating because this is a subject that is clearly understudied,” Dr. William Schaffner, a professor in the Division of Infectious Diseases at Vanderbilt University Medical Centre in Nashville, commented.
“I cannot remember another study similar to this with other vaccines,” the professor added.
According to reports from the American Cancer Society, lymph nodes are found across the body in places including the neck, chest, abdomen, and armpits. “If the immune cells in those lymph nodes are restimulated in the same place, there is a greater immunological response,” the study further noted.