Iowa officials are making a one-time booster shot for whooping cough a requirement for school enrollment.
The state Department of Public Health says the requirement for students enrolling in seventh grade in the fall becomes effective Wednesday. Officials say it will reduce whooping cough cases, which surges every few years.
Children usually receive the bacterial vaccine when they're toddlers. They're recommended to get a booster dose around 11 or 12 years old. The booster shot also includes vaccines against tetanus and diphtheria.
The change will require the vaccine be given to students enrolling in grades seven and up if born on or after Sept. 15, 2000.
The National Immunization Survey says about 74 percent of Iowa teenagers have received the Tdap vaccine. The national average is about 78 percent.