Over the past couple of weeks I have been fighting the flu. During this time, I’ve been searching for the best ways to prevent and combat the nasty illness. In fact, the last post I did was about how cleaning your house can actually help fight the spread of flu germs at home. According to an article by The Wall Street Journal, having a humidifier may be one of the best ways to “keep the flu at bay”. It also explains why the winter seems to be the worst time for the flu virus. Here is that article from The Wall Street Journal.

Burning Question | Why Is Flu Common in Winter?

Scientists have struggled to understand the correlation between cold weather and the flu. This winter has seen a particularly severe flu season for a number of reasons. A wintertime spike in flu cases isn’t only because of the chill outside, says Linsey C. Marr, a professor of civil and environmental engineering at Virginia Tech. It’s also because of the conditions inside.

The Air Test

The link between the flu virus and air humidity has long been studied, but the results were never definitive. Last year, Dr. Marr, her doctoral candidate, Wan Yang, and Elankumaran Subbiah, a professor at Virginia-Maryland Regional College of Veterinary Medicine, sought to put the question to rest. They figured out the flu kept its virulent characteristics best in human mucus, which Dr. Marr took from the dripping nose of her 1-month-old baby. They spiked droplets of human mucus with live flu virus, and then exposed it to air with varying levels of moisture.

In the study, published in 2012 in the journal PLoS One, the researchers found the virus survived best at humidity below 50%, similar to the conditions found indoors in “a really heated building,” says Dr. Marr. “The virus is happy if the mucus droplet completely evaporates and leaves it floating around” in the air.

“It’s also fine in humidities above 98%, which you find in the rainy season in the tropics,” she says, where the conditions outside resemble the environment the virus finds in the body. “But in between, in a humidity of 50% to 98%, the virus doesn’t survive very well.”

The presence of influenza is quite rare in the spring, summer and fall, when people don’t use indoor heating as much and the humidity tends to be in the comfortable 50%-to-70% range, says Dr. Marr. But in the winter, when air from outside is heated and becomes drier, the flu virus survives well.

In other words, give a virus a dry room heated to 70-to-80 degrees Fahrenheit, and you’ve created the perfect conditions for it to thrive, she says.

As for why this winter’s flu season seems especially bad, Dr. Marr believes it is because of the particular strain of the virus, H3N2, which causes “stronger” symptoms, as well as an early start to the season. “There are many, many factors that affect the transmission of influenza,” she says. “Humidity and the survival of the virus in airborne droplets is just one piece of the puzzle.”

What You Can Do

A humidifier might be the best product to keep the flu at bay, Dr. Marr says. “If you can humidify to about 50%, but not above 60% [which can cause mold], you might reduce your chances of getting the flu,” she says.

Dr. Marr uses a digital clock that tells temperature and humidity, so she can adjust the moisture in the air accordingly. That way, she says, “if there is a sick person who comes into my home and is coughing and sneezing, and their droplets are floating all over the place, the virus won’t last very long—hopefully.”

Of course, she says, common-sense measures help, too. Get the flu vaccination in the fall, as soon as it is available. Get out of a dry room where someone is coughing and sneezing. Stay home if you’re sick or have children stay home if they are. And consider wearing a good-fitting mask, with no gaps around the nose or mouth, in public.