It’s that time of year again: coughing, wheezy, sticky people all around you, and that dread in the pit of your stomach that you’re about to get sick. What do you do? Conventional wisdom says that to avoid spreading colds or the flu, you should wash your hands frequently—ideally using antibacterial soap—and cover your mouth when you cough.
But it turns out that sometimes, conventional wisdom is just wrong (sorry about that, mom!). We pored through scientific studies and talked to medical experts to find that some of these oft-repeated tips don’t tell the whole story—while others might actually be harmful. Here’s the truth about colds and the flu. (Spoiler: You should still cover your mouth when you cough.)
- Talking, yelling and even breathing spread the flu.
It’s not just coughing: Merely breathing releases tiny particles that can contain flu viruses. Unfortunately, these particles are smaller than a human blood cell, meaning they’re pretty difficult to avoid. A 2013 study found that these fine droplets actually contain around 8.8 times more flu viruses than the coarse droplets you can see when someone sneezes (ew).
One consequence of this proliferation of droplets? You might want to avoid people who yell a lot. A recent study on the aerosols produced during human speech, which was presented at the American Physical Society’s Division of Fluid Dynamics conference this year and is pending publication in a peer-reviewed journal, expanded this research to find that yelling produces 50 times more aerosol particles than talking in a normal voice.
Yet another reason to avoid topics like sports and politics at your next holiday gathering.
- Surgical masks won’t protect you.
You may be surprised to learn that those people wearing slightly-dystopian surgical masks on the subway aren’t protecting themselves: they’re protecting you. According to the Centers for Disease Control, surgical masks can help stop you from spreading your flu to others, by catching most of the fine particles you breathe out. However, they can’t always stop a mask-wearer from getting sick themselves, which is why the CDC doesn’t recommend them for the general population. Because they’re not airtight, they don’t catch all the particles in the air that might contain viruses.
While public health experts know a fair amount about how flu spreads from person to person, it isn’t as clear how these diseases spread across cities or countries, says Rumi Chunara, an assistant professor in computer science and engineering and global public health at New York University. Chunara is pioneering research into this complicated health phenomenon by turning to an unlikely partner: snot samples. Her project, “Go Viral,” has been collecting nasal samples from Americans since 2013 and is still going strong. Study participants get a kit with a special Q-tip, a “preservation tube” and a mailing label. (Sign up here!)
- You probably won’t get sick from shaking a sick person’s hand.
We know, we know. Your mother always told you to wash your hands when you’re sick. And she wasn’t wrong: It’s true that hand-washing or using an alcohol-based disinfectant kills two classes of virus that cause the common cold (rhinovirus and rotovirus). But that advice won’t help you when it comes to influenza. “All the good studies for how influenza virus transmits suggests (that) you have to inhale the virus through your nose or mouth,” says John Swartzberg, clinical professor emeritus in the school of public health at the University of California at Berkeley. “There isn’t much evidence at all” that the influenza virus is commonly transmitted by hand, he adds. (No, this is not a free pass to stop hand-washing, Swartzberg says.)
That’s also means that simply coming into physical contact with a sick person probably isn’t enough to spread the flu. So no, it isn’t unreasonable to ask your partner to cuddle with you on the couch even though you’re feeling flu-y. “The only way you’d transmit [the flu would be] rubbing your cheek against them, and then put your hand to your cheek, and then touch your mouth or your eye,” says Swartzberg. But as you’ll recall from Tip 1, cuddling does put you within the 6-foot radius that flu viruses can spread in breath. So Swartzberg helpfully advises: “Cuddle with someone, as long as they hold their breath.”
- You could get a cold from touching something a sick person touched.
Not to freak you out, but viruses can live on inanimate objects for up to 72 hours. Moreover, cold and flu viruses last longer on hard surfaces (like stainless steel) than soft ones (like your couch). “So if you wear gloves, it might not last as long,” Chunara points out. That said, she and Swartzberg advocate common sense. “Yes, we live in a sea of microorganisms. Yes, they live on inanimate objects,” Swartzberg says. “The vast majority of these aren’t going to cause disease … that said, if I’ve been around somebody who has an infectious disease, I wouldn’t want to share a pillowcase with them.”
- Forget the extra vitamin C.
If some is good, more is better, right? Not always. People who aren’t vitamin C deficient don’t need to overload their bodies with more in an attempt to fight off a cold. “The idea of boosting your immunity is enticing,” reads the online health publication of Harvard Medical School. Yet while “taking a daily multivitamin and mineral supplement brings health benefits of many types … Taking megadoses of a single vitamin does not. More is not necessarily better.”
Other remedies to toss? Most herbal supplements and echinacea, says Swartzberg. “There’s nothing in the literature that supports that it’s any better than placebo,” he says.
So how do you really avoid getting sick this season? “Avoid people who are sick,” he says. “Especially kids … I call them germbags. Don’t be a schoolteacher, don’t be a pediatrician, don’t be a grandparent.” Easy enough, right? Oh, and get a flu shot. In a good season, it’s about 70 percent effective at preventing flu; even if you’re not the type to get sick, it may prevent you from carrying viruses and passing them on to another person, Swartzberg says.
- We’re closer than ever to a universal flu vaccine.
Every year, we make a new flu vaccine by studying the strains present in the Southern Hemisphere during their winter. Scientists are essentially making an educated prediction as to what this year’s strain will be—which is why some years the vaccine isn’t as effective.
But that may be about to change. Earlier this year researchers announced that they had designed—but not yet created—a vaccine that covers 95 percent of U.S. flu strains and another that works on 88 percent of worldwide strains. Also this year, the National Institutes of Health researchers identified three types of antibodies that, in vitro, neutralized “diverse subtypes” of flu viruses.
“It’s going to happen,” Swartzberg says. Until then, though: Cover your mouth when you sneeze, yell or breathe.