Waning Protection after Fifth Dose of Acellular Pertussis Vaccine in Children

Before a child reaches the age of seven in the United States they receive five doses of the acellular pertussis (DTaP) vaccine. It was unknown how long the child would be protected after their fifth dose of the DTaP vaccine. A study was done to see how long their protection of the vaccine lasted after their fifth dose of the DTaP vaccine. In order to do this they assessed the risk of pertussis in California from 2006-2011 which included a large outbreak of pertussis in 2010. The study compared children from the age’s four to twelve who had pertussis with two sets of controls which were: those who were negative for pertussis and those who closely matched controls from the general population of health plan members. Logistic regression was used to examine the risk of pertussis in relation to the duration of time after the fifth dose of the DTaP vaccine.  The results concluded that the children who were positive for pertussis were more likely to have received the fifth DTaP vaccine dose earlier and the children who were negative for pertussis. This resulted in the conclusion that children who receive the fifth dose of the pertussis vaccine and other doses after that were still at risk of getting pertussis because the protection against it went down.

                Many children are at risk each year of having pertussis. Parents count on the DTaP vaccine to protect their children from getting pertussis and after so many vaccines it is no longer as effective. This effects American’s because more children are becoming at risk for pertussis after the fifth dose of the DTaP vaccine. This affects people in other countries whose children are beginning to receive the vaccine for pertussis because the parents need to know that it will not be as effective the more times it is received.  

http://www.nejm.org/doi/full/10.1056/NEJMoa1200850