Source: Journal of the American Medical Association | Vol:Vol. 308 | Page: 2126
By: Misegades, Lara K. ; Winter, Kathleen ; Harriman, Kathleen
Among California children aged four to 10 years, those who had pertussis in 2010 were less likely to have received the full five-dose series of the diphtheria, tetanus, and acellular pertussis vaccine (DTaP) compared to others. In a new study, researchers sought to evaluate the association between pertussis and receipt of five DTaP doses by the time since fifth DTaP dose. The study included 682 cases among children in 15 counties in California and 2,016 controls. Of those studied, 53 patients (7.8 percent) and 19 controls (0.9 percent) had not received any pertussis vaccines. The children who contracted pertussis had a lower odds of having received all five doses of DTaP. In addition, children with pertussis were less likely to have received their fifth dose within the prior 12 months compared to controls. The estimated vaccine effectiveness declined each year after receipt of the fifth dose of DTaP. A small proportion of children in California were unvaccinated and therefore susceptible to pertussis, but the researchers suggest that waning immunity from DTaP vaccination may have created an even larger pool of susceptible individuals, contributing to the 2010 pertussis epidemic in California.