Tdap vaccination during pregnancy interrupts a twenty-year increase in the incidence of pertussis

Dean Langsam, Emilia Anis, Eric J. Haas, Ruslan Gosinov, Matan Yechezkel, Itamar Grotto, Erez Shmueli, Dan Yamin*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

13 Scopus citations

Abstract

Pertussis incidence in developed countries, including Israel, has increased over the past two decades despite the addition of two booster doses in children. However, as pertussis is characterized by a multi-annual periodicity, and since clinical diagnosis can miss cases, determining disease trends at the population level is challenging. To bridge this gap, we developed a simple statistical model to capture the temporal patterns of pertussis incidence in Israel. Our model was calibrated and tested using laboratory-confirmed cases of pertussis for the Israeli population between 1998 and 2019. The model identifies a clear four-year periodicity of pertussis incidence over the past two decades that is identical to the one observed in the pre-vaccine era. Accounting for this periodicity, the model shows a 325% increase in pertussis incidence from 2002 to 2014. These multi-year trends were interrupted shortly after the introduction of routine immunization of Tdap vaccine in pregnancy in 2015, after which we found a 59.7% (95% CI: 57.7–61.6%) decline in pertussis incidence and a 49.5% (36.0–61.6%) decline in hospitalizations compared to the model's projection. While this sharp decline cannot be fully attributed to the newly introduced vaccination policy, sharper reductions of 71.2% (65.6–76.1%) in incidence and 58.4% (39.6–72.7%) in hospitalizations, have been observed in infants of age two months and below - young infants that have yet to become vaccinated and are more likely to be protected by maternal vaccination. Our work suggests that Tdap vaccination during pregnancy is a promising policy for controlling pertussis. Furthermore, due to the stable periodicity of pertussis, public health decision-makers should invest continuous efforts in the implementation of this strategy with additional reinforcement in expected peak years.

Original languageEnglish
Pages (from-to)2700-2706
Number of pages7
JournalVaccine
Volume38
Issue number12
DOIs
StatePublished - 10 Mar 2020

Funding

FundersFunder number
Israeli National Institute for Health Policy Research
Israel National Institute for Health Policy Research164-16

    Keywords

    • Epidemiology
    • Maternal immunity
    • Periodicity
    • Pertussis vaccination
    • Tdap
    • Vaccination

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