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Baby, It’s Cold (Season) Outside!

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“Don’t go outside with wet hair, you’ll catch a cold!” 

“Wear a hat so you don’t get sick!” 

“Ew, don’t use the same glass as him, he has a terrible cold.”

We’ve all heard these and many other “facts” about how you might catch a cold, but which ones are true and which are simply something to sneeze at? We sat down with Anne Norris, MD, an associate professor of Infectious Diseases, to find out.


Q: Can you get a cold from going outside with wet hair?

A: Several interesting and somewhat gross studies in the last century compared the incidence of getting a cold when exposed to a cold virus among people who were deliberately chilled, wet, or underdressed versus people who were comfortable and warm, and there was no difference. It might be unpleasant to go outside with wet hair in the wintertime, but you aren’t increasing your risk of getting a cold virus any more than if you went out in public with dry hair.

Q: Does going outside without a hat or coat make you more likely to get sick?

A: This goes along with the wet hair myth; you can’t catch a cold from being cold. While studies do show that more people come down with colds in the winter, it’s probably from being inside in close quarters with other people due to the weather and not exposure to the weather itself that causes viruses to spread. Fresh air is really good for you, no matter what time of year, so get outdoors when you can, but do bundle up if it’s extremely cold because you can get frostbite and other complications from exposure to cold that have nothing to do with the cold virus.

Q: Can stress make you sick?

A: This one actually has some truth to it. Both increased stress levels and reduced sleep duration have a direct relationship with the risk of acquiring a cold if exposed to a cold virus. During my annual lecture on infectious diseases myths and facts, I always tell medical students that they need to make sure they get their sleep and try to de-stress if they want to stay cold-free.

Q: Can airplane travel cause a serious infection??

A: The short answer is that it is very unlikely, but possible. Studies have shown that airborne illnesses like SARS and influenza have been spread during airplane travel, but these events are very rare. Laminar air circulation and HEPA filters are thought to reduce exposures greatly. One of my colleagues famously claims that airplane air is some of the safest air you can breathe. One potentially emerging risk is that of measles, which is highly contagious via airborne means. When vaccination rates were very high, measles was not an air travel risk, but recent outbreaks have occurred from exposures on planes.

Q: Can eating or drinking after a sick person make you sick?

A: This is a tricky one because, much like airplane travel, it really depends on the illness that is being spread. If there is a gastrointestinal illness going around, then yes, eating or drinking after someone, and especially sharing a bathroom with them, can absolutely make you sick. Some GI viruses, like norovirus, are extremely contagious. I usually tell people with a GI virus to pick one bathroom to be sick in, only use that bathroom, and tell everyone else in your home to avoid it.

As for catching a cold, it’s unlikely. Rhinovirus is just that – the virus of the nose – so sharing saliva, such as by immediately drinking or taking a bite after someone with a cold has will probably not transmit enough of the virus to get you sick. But EBV, the virus that causes mononucleosis, is present in high concentrations in saliva and has been associated with exchanging oral secretions, most famously in the form of kissing.

Q: Does taking supplements such as Zinc, Vitamin C, or Echinacea keep you from getting sick?

A: There is little to no evidence that these remedies can prevent or substantially shorten the length of a cold for most people, and in fact, overuse can have some negative side effects. Zinc can cause stomach cramps, nausea, headaches, and in some cases can even cause people to permanently lose their sense of smell. And too much vitamin C can also cause nausea, vomiting, and in severe cases, even kidney stones. So, if you want to take these supplements, follow the recommended dosing advice.

Q: How are most colds actually transmitted?

A: The common cold is caused by the Rhinovirus, which is a virus that is found in the nose and nasal passages. The best way for the virus to be transmitted is via the nose, as it only takes a minuscule amount of virus to cause an infection.

Most people with a cold tend to touch their noses a lot and then touch something else – a doorknob, a refrigerator handle, etc. Then you come along behind them, touch that same doorknob and perhaps you touch your nose or the area around your nose, thus exposing yourself to the virus. Other studies have shown that when rhinovirus is put in the eye or the mouth, the likelihood of transmission is actually very low compared to inoculation directly into the nose.

Q: What can be done to reduce the risk of catching a cold?

A: The best way to prevent a cold is to be diligent about washing your hands or using hand sanitizer. Try to avoid touching your face, especially your nose, to prevent the most vulnerable ways for a cold virus to infect you. And most importantly, if you do get come down with a cold, do yourself and your colleagues a favor – stay home and rest for a few days!

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