PHILADELPHIA (February 3, 2016) - Cases of pertussis (whooping cough) have increased dramatically over the past five years, putting infants at risk of serious illness or death. Most infants are infected by a caregiver who has not received a Tdap (tetanus, diphtheria, and pertussis) booster, so caregiver immunization is particularly important. However, many caregivers go unvaccinated, and new strategies are needed to convince those living with infants to get the Tdap booster.