. Author manuscript; available in PMC: 2018 Nov 29.

Published in final edited form as: Clin Infect Dis. 2017 Nov 29;65(12):1977–1983. doi: 10.1093/cid/cix724

Table 3.

Effectiveness of Maternal Tdap Vaccination at Preventing Infant Pertussis, by Timing of Vaccination

	Cases		Controls		Multivariable VE^a, % (95% CI)
Total	240	%	535	%
Unvaccinated	104	43.3	177	33.1	REFERENCE
Before pregnancy	24	10.0	67	12.5	50.8 (2.1 – 75.2)
1^st or 2^nd trimester	5	2.1	27	5.1	64.3 (−13.8 – 88.8)
3^rd trimester	17	7.1	90	16.8	77.7 (48.3 – 90.4)
After pregnancy	90	37.5	174	32.5	4.9 (−49.3 – 39.5)

Abbreviations: CI, confidence interval; VE, vaccine effectiveness

The following variables were included in the final model: household size >2 persons, maternal education, household member with pertussis diagnosis, and infant age (weeks).