Estimates of high pertussis susceptibility in infants suggest a need for greater public health efforts to increase DTaP vaccine coverage in children and Tdap coverage in pregnant women, according to results of research by Lana Childs and Robert A. Bednarczyk, PhD.
There were 32,971 pertussis cases reported in 2014, a 15% increase over 2013; most cases occurred in children who were too young to be fully vaccinated and in preadolescents with waning immunity from their vaccines. In the United States, vaccine coverage during childhood tends to be high overall, but DTaP coverage (84% in 2014) “remains lower than coverage for other childhood vaccinations,” they noted.
The 2013 National Immunization Survey of 7,905,672 U.S. children born between February 2011 and June 2012 gathered data on age-specific pertussis-containing vaccine effectiveness; of children 0-23 months of age, an estimated 22% were susceptible to pertussis. Age was a large factor in susceptibility, with 89% of children less than 2 months susceptible to pertussis, compared with 7% of children aged 21-23 months.“Our findings indicate the overall immunity levels of children by 23 months are close [to] or higher than the estimated herd protection threshold for pertussis (93%). However, in sensitivity analysis models with a lower documented vaccine effectiveness, the herd protection threshold was not reached,” Ms. Childs and Dr. Bednarczyk said.“These findings emphasize the need for public health professionals to continue efforts to increase DTaP vaccine coverage in children and Tdap coverage in pregnant women, plan for potential outbreaks, and maintain immunity levels needed to prevent the spread of pertussis.” the investigators concluded.
Read more at (Ped Inf Dis J. 2017. doi: 10.1097/INF.0000000000001537).
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