Whooping Cough Immunity Wanes Quickly

Protection against whooping cough drops quickly after children receive their last dose of vaccine, a new study finds. The study focused on children in Minnesota and Oregon. All were born between 1998 and 2003. More than 400,000 of the children received all 5 doses of the DTaP vaccine by age 6. This vaccine protects against whooping cough (pertussis), diphtheria and tetanus. Researchers looked at records on whooping cough cases in the 6 years after the children got their last vaccine dose. Cases went up each year. In the first year after children completed their vaccine series, there were 15.6 cases of whooping cough per 100,000 children in the study group in Minnesota. By the sixth year, the rate was 138.4 per 100,000. In Oregon, whooping cough cases rose from 6.2 cases to 24.4 cases per 100,000. The journal Pediatrics published the study. HealthDay News wrote about it March 11.