By Tony Lopez

When it comes to vaccines, experts say it matters which arm you get the shot in.

A new study specifically looked at COVID-19 vaccines, but researchers say it can still apply to other vaccinations as well.

Researchers at E-Biomedicine revealed that when it comes to the COVID-19 shot, people who got all of their shots in one arm had a stronger immune response than those who switched it up.

What's the reason for the one-arm theory when it comes to vaccines?

¨Killer T-cells" which fight off viruses were much stronger in same-arm vaccinated patients. These killer T-cells were detected in 67% of people who received both injections in the same arm versus only 43% of those who got them in different arms.

Another theory, according to researchers, is that the vaccine in the same arm targets the same lymph nodes and this makes them more active in fighting off infections.

However, this new study contradicts what we were told at the beginning of COVID-19 when doctors said it didn't matter which arm you chose.

The same goes for flu shots.

Researchers say that you will most likely benefit from always getting vaccinated in the same arm, calling it a consistent message to the body.