Tdap Vaccine Effectiveness and Waning Protection in Adolescents

Tdap (tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis, absorbed) vaccine was recommended in 2006 for adolescents and adults. In response to a pertussis epidemic in Washington State, investigators assessed Tdap vaccine effectiveness and duration of protection in a case-control study of 836 case patients aged 11 to 19 years and 2322 control patients matched by birth year and primary provider clinic.

Case patients were more likely to be white and non-Hispanic compared with controls. Three fourths of all participants had five documented doses for the childhood series; however, only 60% of cases and 58% of controls had a five-dose series that was on the recommended vaccine schedule. Receipt of recommended Tdap vaccination at ag…