Frequency of medically attended adverse events following tetanus and diphtheria toxoid vaccine in adolescents and young adults: a Vaccine Safety Datalink study

Table 3 Risk of a validated medically attended local reaction following Td vaccination, by history of receipt of tetanus and diphtheria toxoid containing vaccinations¹ in the prior five years, among persons with at least five years of enrollment in the MCO prior to the Td vaccination.

Age, years	History of receipt of TDCV in five years prior to Td vaccination	Number Td vaccinations	Estimated number of local reactions²	Event risk (95% CI) per 10,000 Td vaccinations	Incidence rate ratio (95% confidence interval) comparing those with and without a history of a TDCV in the prior five years
9-10	Yes	1,161	2	17.2 (2.9, 53.2)	4.6 (0.6, 35.4)
	No	8,015	3	3.7 (0.8, 17.2)
11-15	Yes	2,876	2	8.2 (2.1, 32.6)	3.0 (0.8, 11.4)
	No	160,933	44	2.7 (1.8, 4.1)
16-20	Yes	1,962	1	5.9 (0.8, 42.5)	1.8 (0.2, 15.6)
	No	27,713	9	3.3 (1.3, 8.2)
21-25	Yes	165	0	0	Not estimable
	No	6,526	6	8.7 (3.1, 24.2)
All	Yes	6,164	6	9.0 (3.7, 22.2)	2.9 (1.2, 7.2)
	No	203,187	63	3.1 (2.2, 4.4)

CI = confidence interval
¹ Includes Td vaccine as well as diphtheria, tetanus and pertussis vaccines administered as part of the childhood vaccination series.
²Based on multiple imputation; the total of the age-group specific estimates may not add up to the overall total due to rounding average values across imputed datasets.

ISSN: 1471-2334