You know that your child could catch the flu from close contact with a classmate, sick sibling or playdate pal. The bigger the family, the more times each year someone is sniffling and sneezing. Single people develop an average of 2.5 viral infections each year, researchers found. Meanwhile, in households with six kids, each child and grown-up can expect to catch 10 such illnesses.

More Offspring, More Illness
For the yearlong study, Utah researchers asked families to report symptoms of illness. They also collected swabs of mucus to test for the presence of viruses.

Families with no children host viruses in their homes about four weeks of each year. Having just one child means someone in the household is sick about 18 weeks of the year; with two kids, it’s 29 weeks. And for families with six kids, nine of every 10 weeks finds at least one member coping with a cough, a cold or the flu.

Keep Viruses Contained
So why do bigger families breed more germs? Droplets of saliva or mucus can carry the flu virus up to two feet. Once they land, viruses can survive up to eight hours. So, one sick kid spewing germs in the air can bring down a whole family.

Fortunately, there’s a lot you can do to prevent a cold and the flu from running rampant through your household. Experts call these strategies “respiratory hygiene.” Using them when one family member gets sick could allow you to step out of the revolving door of disease.

Keep sick children in a separate room from others, when possible. Assign one person to serve as caregiver. Others should limit their contact.
Tell children to cough or sneeze into a tissue instead of their hands. Toss those used tissues immediately into the trash.
Adopt a hand-washing habit. Teach kids to scrub with soap and water for 20 seconds — the length of two rounds of “Happy Birthday.”
Ban the sharing of pacifiers, pens, computers, drinking cups, utensils, towels and toothbrushes.
Wash laundry in hot water. Clean and disinfect frequently touched surfaces, such as toys, doorknobs and phones. Use soap and water or a bleach-and-water solution.
Young children, especially those younger than age 5, can face serious complications from illnesses like the flu. Talk with your child’s doctor if you have concerns about any illnesses they might have. The conversation goes better if each kid has a pediatrician or other provider who knows their medical history.