DENVER, Colo. — The Institute of Health Metrics and Evaluation found at least 82% of Americans have been infected with COVID-19, but, that means millions of Americans still haven’t been infected. Now, researchers are looking at the science behind those who have stayed healthy.

Researchers are calling these people Novids, for never having COVID, and with nearly 60 million Novids across the country, researchers want to pin down if these people are simply lucky or if genetic factors may be keeping the virus away.

Dr. Thomas Campbell, an internal medicine doctor at the University of Colorado Hospital, said he thinks the biggest reason behind not getting sick doesn’t have much to do with science and will probably frustrate anyone who has been sick.

“I think a lot of that is due to luck,” said Dr. Campbell.

Dr. Campbell said studies have shown, that even with the highly contagious omicron variants, only about 1 in 4 people living with someone who has COVID also got the virus. That low percentage shows him that people can be exposed and just not get sick.

“I think some of it is timing. We know that when a person gets infected with COVID, they are most likely to spread it to other people very early in the course of their illness,” said Dr. Campbell.

Dr. Campbell says research shows that the infection window can be from the day before symptoms appear to about five days into being sick.

“So, if you come into contact with people beyond that window, then the chances of getting infection are less,” he explained.

Still, timing isn’t everything. Genetics may play a role, too. There are several studies happening now to determine if there’s a protein or gene that keeps some people from getting sick.

“A very well-studied example is in the case of HIV,” said Dr. Campbell.

He says about 2% of the Caucasian population does not make a specific protein that HIV cells need to infect the human body. The people without that protein are therefore naturally immune to HIV.

Dr. Campbell said research is happening now to determine if something similar could be true for COVID-19 too.

“There will likely be some genetic factors that would protect certain individuals against getting infected, but I think those will be fairly rare,” he said.

However, the genetic research happening today could help explain why some people get long COVID, and it could help make better treatments for COVID in the future.

“In the case of the co-receptors in HIV, that actually did lead to development of a class of medicines that are used to treat people with HIV,” said Dr. Campbell.

The last reason many people might think they haven’t had COVID: they may have been asymptomatic. Researchers at the University of Bern in Switzerland studied more than 28,000 COVID cases around the world and found 42% of those infected had no symptoms.

For those lucky people who have never been infected, Dr. Campbell recommended the usual preventative measures: vaccination, mask-wearing, and social distancing. But, he also said keeping physically and mentally healthy can be big factors in minimizing or avoiding COVID altogether.