CHAMPAIGN, Ill. (WCIA) — “Now, they have memory for Covid, plus now they went and got the Covid vaccine,” Dr. Awais Vaid said.

He says some people may have extra protection against the coronavirus and not even know it. Many families are getting ready to celebrate their second holiday season during the Covid-19 pandemic. Some will be vaccinated, but some won’t be. Now, a new study is exploring why the virus will attack some people who are exposed and not others.

It could mean future vaccines give people better protection. There’s still a lot of research that needs to be done. For now, it’s another way for experts to understand what Covid does and why some people are more protected than others.

“One person would get infected and they would turn positive and with the same exposure a second person and a third person may be just fine,” Vaid said. “So their immune system may have just been fighting infections a little bit better.”

A lot of us know someone who was exposed to Covid, but never tested positive.

“If you get infected with it, you may not have any symptoms at all, you may not be sick at all, but you still had an exposure,” Vaid said. “The body identified that exposure, it was very mild, so the body did build antibodies.”

Champaign Urbana Public Health Epidemiologist, Awais Vaid, says there’s a reason for that. He says that person may have either had a strong immune system or they may have already been exposed and didn’t realize they had the virus at one point.

“So the next time you get exposed, the body remembers that, it has built antibodies that will fight the infection better,” Vaid said.

It’s not always just antibodies doing the work. A new study done at University College London found that T-cells may have helped some people fight the virus. T-cells are part of the immune system. Some people have T-cells that can memorize previous illnesses, have a rapid response and fight new viruses quickly, including Covid-19.

It’s important research, but Vaid says it’s important to remember that antibodies, or T-cell memory, are not enough protection.

“People think that if they have tested positive then that should be good enough, it should last a lifetime,” Vaid said. “Not every disease is that way.”

He says vaccination continues to be an important layer of protecting against a changing virus.

“The mutations that we see in Covid, its mutating and changing,” Vaid said. “It started with the alpha, then the beta, and now the delta, the body does not recognize all of these mutations as well.”

Vaid says the current Covid vaccines do activate that T-cell immune response, but it’s not direct and not as strong. He says some researchers are developing vaccines to target T-cell response, but they’ll have to see the data before they know how well that works.