My son barely sneezed for the first year and a half of his life. And then he went to daycare.
Enter the cold season I’d heard about from friends: a winter’s worth of viruses, days of drippy noses, and nights of coughing.
My daughter, who just turned one, has it differently. With an older brother in preschool and a revolving door of glassy-eyed, red-nosed little people in her life, she’s already got a few illnesses under her belt. This has made me wonder about the comments parents make to each other about the value of a cold — that it boosts the immune system and makes our kids more resilient.
Is it true — does getting sick early on make our kids healthier down the road?
There’s plenty of support for the common cold’s silver-lining theory. For example, a 2002 study in the Archives of Pediatrics & Adolescent Medicine showed that kids in large daycares (with more than six children) had almost twice as many colds at age two, but a third as many colds at age six, compared to those at home or in small daycares. (By age 13, the effect had worn off). In a 2010 study, 1,238 children were grouped as having home care, small or large day-care and followed until they were eight years old. Compared to the kids at home, those in group care before age two and a half had more respiratory tract infections and ear infections during that time, but lower rates of these infections in elementary school.
— Lauren Jimison
— Kristen Howerton and Sarah James
— Rebekah Kuschmider
The explanation for this is that when a little one is exposed to a virus and her immune system produces antibodies to fight it, those antibodies stick around — making her more likely to skate by the next encounter with that virus symptom-free. It’s not clear exactly how long antibodies stay with us, since there are so many different types and the immune system is highly intricate, but one recent finding gives us an idea of the potential. Scientists looked at people born in 1915 and earlier who had survived the 1918 pandemic flu virus, and found almost all still had strong concentrations of antibodies to that virus — almost 90 years later. If antibodies to the common cold are anywhere near as long-lasting, you can see how they could protect our kids as the years go on.
I talked to a pediatrician, Yael Wapinski, who practices in Manhattan, about colds and immunity. She tells parents who fret over putting their babies in daycare, “Yes, she’ll get sick more often. But our bodies are built to fight infections. Kids are going to be exposed, it’s just a matter of time.” She follows a middle-of-the-road approach to germs with her three little kids, forgoing constant hand-sanitizing for reasonable hand-washing habits — before and after meals, and around any newborn baby. “You can’t live in a bubble,” she says. “Nor should you.”
The idea that stuffy toddler noses lead to clean bills of health later in life is related to the “hygiene hypothesis” — a more sweeping idea that in our modern, sterile world, we are no longer exposed to the variety of microbes our bodies were built to handle — and this makes for widespread conditions such as allergies and asthma. Last year, an animal study in the journal Science unpacked this phenomenon a bit. Researchers found that mice raised in sterile environments developed more severe symptoms of asthma or colitis than their germ-exposed counterparts. Being in a sterile environment actually caused certain genes to be expressed more strongly in the mice, tripping off a biological pathway leading to inflammation, and predisposing those animals to the health conditions. There also appeared to be a critical period — the mice needed to be exposed to germs early in life for the best result.
Back in my house, the science is all well and good, but looking at my small, chubby-cheeked one-year-old, I’m not necessarily convinced. For one thing, it’s true that when researchers line up thousands of kids and track their colds, they see a pattern — but that doesn’t mean my daughter will follow suit.
Also, the common cold is caused by literally hundreds of different viruses. Daycare or not, if our kids pick up a handful of bugs every year and carry the immunity with them, there will always be hundreds more out there that their bodies have never seen. I feel good about letting my kids dig around in the dirt at the park, but I think I’ll continue our regular hand-washing to cut back on sicknesses, at least while we’ve still got a baby in the family. When one of my kids does come down with another runny nose, though, I’ll imagine the tiny army of antibodies they’re building this time around to protect them later on.