Waning Protection after Fifth Dose of Acellular Pertussis Vaccine in ChildrenArchived
A case–control study involving members of a care consortium who were vaccinated with DTaP at 47 to 84 months of age was conducted. Children who received whole-cell pertussis vaccine during infancy or who received any pertussis-containing vaccine after their fifth dose of DTaP were excluded. Children with pertussis confirmed by a positive polymerase-chain-reaction (PCR) assay with two sets of controls were compared to those who were PCR-negative for pertussis and closely matched controls from the general population of health-plan members. They used logistic regression to examine the risk of pertussis in relation to the duration of time since the fifth DTaP dose.
Klein NP, Bartlett J, Rowhani-Rahbar A, Fireman B, Baxter R. N Engl J Med 2012; 367:1012-1019.
Description:
A case–control study involving members of a care consortium who were vaccinated with DTaP at 47 to 84 months of age was conducted. Children who received whole-cell pertussis vaccine during infancy or who received any pertussis-containing vaccine after their fifth dose of DTaP were excluded. Children with pertussis confirmed by a positive polymerase-chain-reaction (PCR) assay with two sets of controls were compared to those who were PCR-negative for pertussis and closely matched controls from the general population of health-plan members. They used logistic regression to examine the risk of pertussis in relation to the duration of time since the fifth DTaP dose.
In total, 277 children 4 to 12 years of age who were PCR-positive for pertussis were compared with 3318 PCR-negative controls and 6086 matched controls. PCR-positive children were more likely to have received the fifth DTaP dose earlier than PCR-negative controls (P<0.001) or matched controls (P=0.005). Comparison with PCR-negative controls yielded an odds ratio of 1.42 (95% confidence interval, 1.21 to 1.66),
ECDC comment:
The authors assess the risk of pertussis in children in California relative to the time since the fifth dose of DTaP from 2006 to 2011 (this period included a large outbreak in 2010). They showed that after the fifth dose of DTaP, the odds of acquiring pertussis increased by an average of 42% per year and that protection against pertussis waned during the 5 years after the fifth dose of DTaP. Previous estimates from the literature showed very good protection from acellular vaccines for 5 to 8 years after vaccination [1].
Pertussis used to be transmitted amongst children, however due to waning immunity the pattern has changed and adolescent/adult-to-infant transmission has become frequent. This has lead several countries to strategies recommending booster doses in adolescents and adults.
References:
[1] Wendelboe AM, Van Rie A, Salmaso S, Englund JA. Duration of immunity against pertussis after natural infection or vaccination. Pediatr Infect Dis J. 2005;24:S58-S61