Newer Pertussis Vaccines Not As Effective

Higher rates of pertussis were found in children born in 1998 who received the acellular pertussis vaccine (DTaP), the injection which replaced whole-cell pertussis vaccines (DTwP) in the 1990s, suggesting that the change in vaccine may be related to the current pertussis epidemic.  

Sarah Sheridan, BMed, of Queensland Children’s Medical Research Institute in Brisbane Australia, and colleagues, analyzed data on cases of pertussis reported to the health department in Queensland between 1999 and 2011.

Those who received 3-doses of DTaP showed higher rates of pertussis than those who received DTwP during the pre-epidemic period of 1999-2008 (13.2 versus 5.3 per 100,000 per year) and the outbreak period of 2009-2011 (373.1 versus 113.3 per 100,000 per year).

"The lesser protection provided by DTaP, both as the initial vaccine or full primary course, may be due to linked epitope suppression, when the initial exposure locks in the immune response to certain epitopes and inhibits response to other linked epitopes on subsequent exposures," researchers wrote.

"The challenge for future pertussis vaccine development is to address the benefit-risk trade-off highlighted by our study, and to develop vaccines that induce long-lasting protection from the first dose, without the adverse events associated with DTwP use," they concluded.

-Michael Potts