There were more than nine thousand cases of suspected whooping cough or pertussis in California last year.
A new state law requires all children entering grades seven through twelve to get what is called a T-DAP booster shot this year. Sacramento County Health Officer Glennah Trochet says any child entering those grades who had a booster shot before the age of seven will have to get another.
GLENNA TROCHET: "Last year, ten babies under the age of six months died of whooping cough. All of those babies got the disease from a family member."