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Why do some people never get sick?

The entire office seems to be sniffling, coughing, and sneezing through the winter, but there's that one person who never so much as experiences a clogged nose.
/ Source: TODAY

The entire office seems to be sniffling, coughing and sneezing, but there’s that one person who never so much as experiences a clogged nose.

How is it that some people never get sick? Is it magic? A robust immune system?

“The most obvious reason … is simply that [they] are lucky,” said Stephen Morse, professor of epidemiology at Mailman School of Public Health at Columbia University.

The immune system is both complex and individualized. Researchers know that people have weakened immune systems if they suffer from chronic conditions, such as diabetes, or engage in poor behaviors, such as smoking. But there is little known about why some people never get sick.

“It’s kind of a tough topic. It’s likely due to a combination of ingredients,” said Dr. William Schaffner, professor of medicine in the division of infectious diseases at Vanderbilt University School of Medicine.

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While experts are unsure exactly why some people seem immune to illness, they do have some guesses.

“Some people are simply healthier than others,” said Schaffner, a widely respected epidemiologist. “There are people who lead healthier lifestyles … they are less likely to become ill and it is a milder illness [when they do].”

Working out and eating healthy foods boost the immune system, evidence shows, improving a person’s response to illness.

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“If we study certain markers … of your immune system, we can see some enhancement of the immune system function. No one, I think, has studied rigorously whether that actually translates into fewer colds,” Schaffner said.

People who get plenty of sleep and manage with stress well might be better able to resist germs, said Dr. Amy-Crawford-Faucher, director of WPIC Inpatient Primary Care at UPMC Department of Family Medicine. Being well-rested and less stressed helps the body better fight attackers.

Another reason people don’t get sick? Constant exposure to the over 200 different kinds of cold viruses, for example, builds up their immunity.

“It is said that pediatricians are some of the healthiest people around. Why? They are exposed to all those snotty nosed kids … during their training. By the time they are out there, their bodies have seen all viruses,” Schaffner said.

And, the body learns to defend itself.

“Your body basically remembers every germ it encounters, which is not to say you can’t get sick again. Once you’ve been exposed your body knows how to jump in [and protect you],” Crawford-Faucher said.

Building up immunity could explain why mom never gets sick even though the rest of the family gets every illness out there. But also it could be that mom has a lot of healthy relationships, protecting her from illness.

“People who are more socially connected in terms of positive relationships have fewer colds,” said Dr. Jon Temte, a University of Wisconsin Health Family Medicine physician and chair of the Centers for Disease Control and Prevention's Advisory Committee on Immunization Practices. “They don’t just report fewer colds, they have fewer colds.”

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While they don’t know why exactly, Temte suspects that people with good social bonds are mentally healthier.

And, then there’s folks who contract viruses, but don’t experience illness, what’s known as an asymptomatic infection.

“We’re learning more and more about this group called super spreaders. These are people who are responsible for spreading [illness] but don’t get sick themselves,” said Temte. “ I think the science behind that is basically in its infancy.”

For now, why some people resist a cold or the flu remains mysterious.

“We don’t understand all the nuances,” said Morse. “When you ask a good question like that … it shows how much we don’t know.”

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This article was originally published in February 2015.