Is Getting Sick Good for Preschoolers?

By Brad Broberg  

No parents send their children to day care or preschool just so they can come home with a runny nose, scratchy throat and a fever. But it happens, and in most cases, it's not a bad thing. In the same way preschoolers must learn to play with others, recognize numbers and recite the alphabet, their immune systems must learn to resist viruses. It just so happens that day-care centers and preschools provide a perfect environment for that to occur. 

"None of the kids know how to wipe their noses very well and they're touching everything," says Jeannette Harris, a certified infection control professional at MultiCare Health System in Tacoma, Washington. "They're coughing and sneezing. They're just juicy. They're constantly shedding viruses all the time. That's how viruses get spread." 

Sounds yucky, and children who attend large day cares and preschools experience more colds earlier in their lives, but in the long run, that early exposure can be beneficial. A University of Arizona study published in 2002 concluded that children ages 6-11 who had previously spent time in large day cares or preschools (those caring for more than five unrelated children) suffered fewer colds than those who were cared for at home. 

It's a trade-off, for sure, but by developing greater resistance to cold viruses when they're younger, children are less likely to stay home sick as often when they begin school. The key words are "as often." Since there are so many cold viruses – and they mutate so fast – it's impossible to develop resistance to them all.

Building blocks
Those “juicy” symptoms of a cold – sneezing, runny nose, fever – are the body's way of trying to eliminate disease-causing pathogens before they can cause a dangerous infection. 

There's more to it than that, however. When the body encounters a pathogen for the first time, it develops antibodies against that particular pathogen. If the same pathogen ever strikes again, the antibodies will, if all goes according to plan, neutralize it before it can do any damage or trigger major symptoms. That's how humans acquire immunity to various diseases: one pathogen at a time. 

Newborns inherit their mother's antibodies, and breastfed babies get a further boost against infections, diseases and allergies. The longer they’re breastfed, the bigger the boost. (That’s a big reason why the American Academy of Pediatrics recommends mothers breastfeed for at least the first year of a child's life.) But even with the protection provided by maternal antibodies, within a few months babies must begin to build their own antibodies. "They have a [complete] immune system," says Harris. "They just haven't been exposed to a lot yet."

Studies have shown that the number of children affected by autoimmune and allergic conditions is much higher in developed countries," says Dr. Maria Wright, a pediatrician at Kaiser Permanente South Sacramento Medical Center. Bottom line? "It's important for parents to not be obsessed with cleanliness."

Too few germs?

The buzz lately is that today’s children may be getting too little contact with the germs that cause infection but also help children build a strong immune system. "There's a lot of discussion out there about whether we're trying to keep kids too clean," says Harris. Another factor: "It used to be we had large families where kids were exposed to a lot more things." 

In wealthy Western countries, antibiotics, clean homes – even indoor plumbing – all add up to fewer childhood infections. Generally speaking, that's a good thing. But the so-called "let them eat dirt" theory says that this limited exposure to germs has led to increases in certain autoimmune and allergic conditions, such as Crohn's disease and asthma. 

"I wouldn't encourage people to let their children eat dirt," says Harris. But experts say moderate exposure to germs early in life trains the immune system to respond properly later in life, helping to ensure that it doesn't greet an antigen by overreacting (as in allergies) or by attacking the body itself (as in autoimmune diseases). 

Of course, none of this is meant to suggest that exposing children to disease is an acceptable alternative to building immunity through childhood vaccinations. "The world today has some pretty serious pathogens out there," says Harris. "Vaccinations are the number one reason kids are as healthy as they are today."
 

Brad Broberg is a freelance writer and a dad. A former newspaper reporter and editor, he writes about business, real estate and health care.