TUESDAY, March 24, 2020 (HealthDay News) -- The new coronavirus continues its steady march through the U.S. population, bringing with it a second plague: potentially dangerous myths and rumors about COVID-19, spread via the internet.

You may have already heard some of these coronavirus myths, which, if subscribed to, could at best mean wasted effort or -- at worst -- make you even more vulnerable to getting ill.

Now, experts at the University of Texas Health Science Center at Houston (UT Health) tackle a number of these rumors, to help you sort fact from fiction:

'Face masks will keep the uninfected safe.'

False. Except when used under high-exposure conditions, such as by health care workers, donning a face mask every day (especially cheap paper or cloth masks), doesn't keep viruses from infecting you.

"Those who are not ill or on the frontlines of medicine may not benefit from wearing a mask," said Dr. Michael Chang. He's assistant professor of pediatrics at McGovern Medical School, and an infectious disease specialist with UT Physicians.

"Wearing a mask when you are not sick essentially gives you a false sense of confidence that you don't need to wash your hands as often, or not touch your face as much," Chang explained in an UT Health news release. "And, because masks can be uncomfortable, you may actually touch your face more. In addition, contamination can occur when masks are taken off and put back on."

Also, when lay people snap up face masks needed to protect health care workers, that puts everyone at risk. Every nurse or doctor infected means fewer people to care for the very ill.

Late last month, U.S. Surgeon General Dr. Jerome Adams acknowledged the situation, tweeting " "Seriously people -- STOP BUYING MASKS!"

One exception to the rule: If you develop symptoms of COVID-19, such as fever and coughing, wearing a face mask could help lower the transmission of infectious droplets in air, experts say.

'Lots of vitamin C will ward off COVID-19.'

False. There is no evidence that taking extra vitamin C will fight against COVID-19, said Dr. Susan Wootton, a UT associate professor of pediatrics and an infectious disease pediatrician.

"In fact, our body can only absorb a certain amount of vitamin C at a time and any excess will be excreted. So those who are stocking up on the vitamin are not benefiting from the extra intake," Wootton said in the release.

'Like colds and flu, COVID-19 will fade with warmer weather.'

False -- maybe. There is no conclusive proof that the coronavirus will die off once the weather turns warm.

"Because this is a new virus, we aren't sure," said Catherine Troisi in the release. She's an epidemiologist and associate professor in the Department of Management, Policy, and Community Health at UT Health's School of Public Health.

One recent study, led by virologist Dr. Mohammad Sajadi of the University of Maryland School of Medicine, has suggested that coronavirus might prefer cooler, more humid climes.

"Based on what we have documented so far, it appears that the virus has a harder time spreading between people in warmer, tropical climates," Sajadi said.

But even if that's so, the fact that humans have no immune experience against the virus means it will probably continue to spread during the Northern Hemisphere's summer, other experts countered.

"We hope that warmer weather will help, but there is no guarantee," Troisi said. "What ultimately helps is that summertime means kids are not in school anymore, and they are less likely to pass viruses around."

'Drinking water every 15 minutes helps prevent coronavirus illness.'

False. This internet rumor is based on the fallacious notion that water "washes" virus into the hostile acidic environment of the stomach. The notion is a false one, and gargling with warm water won't help protect against the coronavirus either, said Dr. Luis Ostrosky, professor of internal medicine and an infectious disease specialist at UT Health.

If you are sick, there is a good reason to drink at least some water, however: "It is very important to stay both hydrated and well-rested when recovering from any infection," Wootton said.

'Coronavirus will soon mutate into an even more dangerous strain.'

False. The coronavirus is not likely to mutate into a more deadly strain, according to Chang.

"Viruses mutate pretty frequently, but not all mutations have to be bad," he explained. "Many mutations in viruses are silent, and some can even lead to a strain that is less fit with less virulence."

In fact, vaccine developers often take advantage of the latter fact, using harmless forms of a virus -- one with genetic mutations that make it less pathogenic -- to use in new vaccines, Chang said.

"Given all of the above, it is very unlikely for COVID-19 to develop a mutation that makes it deadlier," he said.

'Hand-washing only kills coronavirus if water is hot.'

False. Washing your hands with hot water isn't any more effective than with cold water. Frequent hand-washing with soap and water is recommended as one of the best ways to limit the spread of the coronavirus, but the temperature of the water doesn't matter.

When "washing hands with soap and water, it's really the mechanical scrubbing action that's cleaning your hands," Chang explained. "You can use warm or cold water. You have to be sure you wash/scrub long enough (at least 20 seconds) and completely dry your hands."

Twenty seconds might be longer than you realize: It's roughly as long as it takes to hum "Happy Birthday" twice from beginning to end.

More information

The U.S. Centers for Disease Control and Prevention outlines how to protect yourself from the coronavirus.