T-Cell..

 

When you go to get your newly updated Covid-19 booster this fall, you might want to choose the arm the vaccine goes in carefully.

The immune response may be stronger if your booster goes in the same arm as your last Covid-19 shot, according to a study published August 11 in the journal eBioMedicine.

“The question seems so banal, so trivial that nobody before has thought to ask it,” study coauthor 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.

Two weeks after the booster, the number of “killer T cells” was significantly higher in those who had both shots in the same arm, according to the study.

Those cells, which attack and destroy the other cells they target, were present in 67% of the same-arm cases and only 43% in people who had their injections in different arms, according to study coauthor Laura Ziegler, a doctoral student at Saarland University.