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Waning Tdap Effectiveness in Adolescents.
Pediatrics. 2016 Mar; 137(3):e20153326.Ped

Abstract

BACKGROUND AND OBJECTIVE

Because the effectiveness of diphtheria-tetanus-acellular pertussis (DTaP) vaccine wanes substantially after the fifth dose at ages 4 to 6 years, there is a growing cohort of adolescents who rely on tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) for protection against pertussis. Yet despite high Tdap vaccine coverage among adolescents, California experienced large pertussis outbreaks in 2010 and 2014. We investigated Tdap vaccine effectiveness (VE) and waning within Kaiser Permanente Northern California among adolescents exclusively vaccinated with DTaP vaccines.

METHODS

We modeled pertussis risk in relation to Tdap vaccination status among adolescents beginning on their 10th birthday. We estimated the hazard ratio (HR) for each subsequent year after Tdap compared with unvaccinated adolescents by using Cox regression, adjusting for calendar time, age, gender, race, and facility. We calculated VE as 1 - HR. We also treated time since Tdap vaccination as a continuous variable and estimated the change in the HR per 1-year increase since vaccination.

RESULTS

On the basis of 1207 pertussis cases, Tdap VE during the first year after vaccination was 68.8% (95% confidence interval [CI] 59.7% to 75.9%), decreasing to 8.9% (95% CI -30.6% to 36.4%) by ≥4 years after vaccination. Adolescents who were more remote from Tdap were significantly more likely to test positive for pertussis than were those vaccinated more recently (HR per year 1.35, 95% CI 1.22 to 1.50).

CONCLUSIONS

Routine Tdap did not prevent pertussis outbreaks. Among adolescents who have only received DTaP vaccines in childhood, Tdap provided moderate protection against pertussis during the first year and then waned rapidly so that litle protection remained 2-3 years after vaccination..

Authors+Show Affiliations

Northern California Kaiser Permanente Vaccine Study Center, Oakland, California nicola.klein@kp.org.Northern California Kaiser Permanente Vaccine Study Center, Oakland, California.Northern California Kaiser Permanente Vaccine Study Center, Oakland, California.Northern California Kaiser Permanente Vaccine Study Center, Oakland, California.

Pub Type(s)

Journal Article
Multicenter Study
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

26908667

Citation

Klein, Nicola P., et al. "Waning Tdap Effectiveness in Adolescents." Pediatrics, vol. 137, no. 3, 2016, pp. e20153326.
Klein NP, Bartlett J, Fireman B, et al. Waning Tdap Effectiveness in Adolescents. Pediatrics. 2016;137(3):e20153326.
Klein, N. P., Bartlett, J., Fireman, B., & Baxter, R. (2016). Waning Tdap Effectiveness in Adolescents. Pediatrics, 137(3), e20153326. https://doi.org/10.1542/peds.2015-3326
Klein NP, et al. Waning Tdap Effectiveness in Adolescents. Pediatrics. 2016;137(3):e20153326. PubMed PMID: 26908667.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Waning Tdap Effectiveness in Adolescents. AU - Klein,Nicola P, AU - Bartlett,Joan, AU - Fireman,Bruce, AU - Baxter,Roger, Y1 - 2016/02/05/ PY - 2015/11/25/accepted PY - 2016/2/25/entrez PY - 2016/2/26/pubmed PY - 2016/7/15/medline SP - e20153326 EP - e20153326 JF - Pediatrics JO - Pediatrics VL - 137 IS - 3 N2 - BACKGROUND AND OBJECTIVE: Because the effectiveness of diphtheria-tetanus-acellular pertussis (DTaP) vaccine wanes substantially after the fifth dose at ages 4 to 6 years, there is a growing cohort of adolescents who rely on tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) for protection against pertussis. Yet despite high Tdap vaccine coverage among adolescents, California experienced large pertussis outbreaks in 2010 and 2014. We investigated Tdap vaccine effectiveness (VE) and waning within Kaiser Permanente Northern California among adolescents exclusively vaccinated with DTaP vaccines. METHODS: We modeled pertussis risk in relation to Tdap vaccination status among adolescents beginning on their 10th birthday. We estimated the hazard ratio (HR) for each subsequent year after Tdap compared with unvaccinated adolescents by using Cox regression, adjusting for calendar time, age, gender, race, and facility. We calculated VE as 1 - HR. We also treated time since Tdap vaccination as a continuous variable and estimated the change in the HR per 1-year increase since vaccination. RESULTS: On the basis of 1207 pertussis cases, Tdap VE during the first year after vaccination was 68.8% (95% confidence interval [CI] 59.7% to 75.9%), decreasing to 8.9% (95% CI -30.6% to 36.4%) by ≥4 years after vaccination. Adolescents who were more remote from Tdap were significantly more likely to test positive for pertussis than were those vaccinated more recently (HR per year 1.35, 95% CI 1.22 to 1.50). CONCLUSIONS: Routine Tdap did not prevent pertussis outbreaks. Among adolescents who have only received DTaP vaccines in childhood, Tdap provided moderate protection against pertussis during the first year and then waned rapidly so that litle protection remained 2-3 years after vaccination.. SN - 1098-4275 UR - https://www.unboundmedicine.com/medline/citation/26908667/Waning_Tdap_Effectiveness_in_Adolescents_ L2 - http://pediatrics.aappublications.org/cgi/pmidlookup?view=long&pmid=26908667 DB - PRIME DP - Unbound Medicine ER -