Whooping cough, or pertussis, is back. And it’s afflicting older children and teen-agers as well as adults at a rate more than 50 percent higher than in the 1980s. Babies who receive the combination DTaP immunization for diphtheria, tetanus and pertussis are protected. But the DTaP wears off, and it’s not available for those over age seven. “First, we need to be vigilant in maintaining immunizations against pertussis in children under seven.” said Dr. Jane Siegel, professor of pediatrics at UT Southwestern Medical Center at Dallas. But what should older victims do’ “For adolescents and adults with a cough lasting longer than two weeks, health-care providers should conduct rapid diagnostic tests,” Siegel said. “If pertussis is identified, then patients and their contacts should be treated with the appropriate antibiotics.” A pertussis vaccine for older people is in development. Studies show that one-third of the dose given children can be an effective booster for teens and adults.