Another bonus: "In the school where the vaccination rate was close to 50 percent, we see some protection extended even to those kids who were unvaccinated," she said. "Their rates of influenza were less compared to schools with lower vaccination rates."

There are simple steps that families can take to fight the flu. The Advisory Committee on Immunization Practices recommends a yearly flu vaccine for everyone 6 months of age and older. Vaccination is critical for people who live with or care for young children or children with medical conditions, to prevent the spread of flu to high-risk children.

Moms can help protect their babies by getting a flu shot during pregnancy. And make sure that family members and caregivers -- including babysitters and grandparents -- are all vaccinated to prevent spreading flu to children too young for vaccination.

While vaccination is the first line of defense, if children do get the flu, prescription antiviral medicines, which include Tamiflu (generic name oseltamivir) and Relenza (zanamivir), are recommended by the CDC as treatment to help ease symptoms and shorten the duration of the illness, Wong said.