Skip to Main Content
TABLE 5

Risk of Pertussis in Vaccinated Children by Years Since Last DTaP Dose, by Age Group at KPNC, January 2006–June 2017

Age at Follow-up (No. DTaP Doses Corresponding to Fully Vaccinated Status)
Ages 19 to <84 mo (4 DTaP Doses); 377 030 Children (1 204 786 P-Y) With 200 Pertussis CasesAges 84–132 mo (5 DTaP Doses); 171 701 Children (496 321 P-Y) With 310 Pertussis Cases
HR (95% CI)aHR (95% CI)bHR (95% CI)aHR (95% CI)b
Years since last DTaP dose (versus <1 y)   — — 
 1 to <2 y 1.40 (0.86–2.27) 1.36 (0.93–1.97) — — 
 2 to <3 y 2.01 (1.05–3.85) 1.96 (1.34–2.87) — — 
 3+ y 5.04 (1.84–13.80) 2.58 (1.49–4.46) — — 
Years since last DTaP dose (versus <3 y) — — — — 
 3 to <4 y — — 1.55 (0.88–2.71) 1.90 (1.17–3.11) 
 4 to <5 y — — 1.37 (0.68–2.76) 2.14 (1.31–3.50) 
 5 to <6 y — — 2.03 (0.92–4.52) 3.42 (2.13–5.50) 
 6+ y — — 2.32 (0.97–5.59) 4.66 (2.81–7.71) 
Age at Follow-up (No. DTaP Doses Corresponding to Fully Vaccinated Status)
Ages 19 to <84 mo (4 DTaP Doses); 377 030 Children (1 204 786 P-Y) With 200 Pertussis CasesAges 84–132 mo (5 DTaP Doses); 171 701 Children (496 321 P-Y) With 310 Pertussis Cases
HR (95% CI)aHR (95% CI)bHR (95% CI)aHR (95% CI)b
Years since last DTaP dose (versus <1 y)   — — 
 1 to <2 y 1.40 (0.86–2.27) 1.36 (0.93–1.97) — — 
 2 to <3 y 2.01 (1.05–3.85) 1.96 (1.34–2.87) — — 
 3+ y 5.04 (1.84–13.80) 2.58 (1.49–4.46) — — 
Years since last DTaP dose (versus <3 y) — — — — 
 3 to <4 y — — 1.55 (0.88–2.71) 1.90 (1.17–3.11) 
 4 to <5 y — — 1.37 (0.68–2.76) 2.14 (1.31–3.50) 
 5 to <6 y — — 2.03 (0.92–4.52) 3.42 (2.13–5.50) 
 6+ y — — 2.32 (0.97–5.59) 4.66 (2.81–7.71) 

—, not applicable.

a

HR estimates are adjusted for sex, race or ethnicity, type of insurance, medical clinic, DTaP vaccination status, and for age and calendar date because risk sets were defined on a calendar time line and stratified by year and month of birth.

b

Same as footnote “a,” except HR estimates are not adjusted for age (ie, risk sets are not stratified by year and month of birth).

Close Modal

or Create an Account

Close Modal
Close Modal