Post-licensure safety surveillance study of routine use of tetanus toxoid, reduced diphtheria toxoid and 5-component acellular pertussis vaccine

Figures & data

Table 1. Summary of demographic characteristics.

Characteristic	Tdap vaccine cohort	Td comparison cohort
Total	124,139 (100.0%)	203,154 (100.0%)
Female	67,067 (54.0%)	104,898 (51.6%)
Mean age in years (range)	32.1 (1–114)	39.0 (1–116)
Race, n (%)
White	53,407 (43.0%)	92,777 (45.7%)
Black	6,740 (5.4%)	10,439 (5.1%)
Hispanic	14,798 (11.9%)	24,291 (12.0%)
Asian	11,207 (9.0%)	18,647 (9.2%)
Pacific Islander	359 (0.3%)	561 (0.3%)
Multiracial	2,039 (1.6%)	4,468 (2.2%)
Native American	463 (0.4%)	836 (0.4%)
Unknown/Other	35,126 (28.3%)	51,135 (25.2%)
Seasonality (time of vaccine), n (%)
Dec–Feb	20,293 (16.3%)	42,397 (20.9%)
Mar–May	35,651 (28.7%)	51,039 (25.1%)
Jun–Aug	49,173 (39.6%)	62,906 (31.0%)
Sep–Nov	19,022 (15.3%)	46,812 (23.0%)

Figure 1. Steps in focusing reviews of outcomes and comparisons in outpatient (OP), emergency department (ED) and inpatient (IP) databases. ^aIRR >1.0 and its 95% CI LB excludes 1.0 on risk-interval cohort and/or historical cohort comparison(s). ^bIRR >1.0 on Td historical cohort comparison; IRR >2 and n ≥ 3 or IRR 95% CI LB >1.5 and n ≥ 5 on risk-interval comparison. ^cPI discretion. ^dPI classified outcomes with statistically elevated IRRs into 4 groups: likely due to confounding by indication; implausible; non-specific; and all other (i.e., potentially plausible). ^eIRR >1.0 and its 95% CI LB excludes 1.0 on Td historical cohort comparison. ^fPer PI discretion, added back 1 outcome (hepatitis) that had not been retained at previous screening step. CI, confidence interval; ED, emergency department; IP, inpatient; IRR, incidence rate ratio; LB, lower bound; n, number of people exposed to Adacel vaccine; OP, outpatient; PI, principal investigator.

Table 2. Prespecified outcomes of interest for the outpatient database.

Diagnostic group	Diagnoses included	Risk intervals (days)
Neurological conditions	Bell's palsy, seizure, neuritis (including optic neuritis), neuralgia, neuropathy, Guillain-Barré Syndrome, encephalopathy, encephalitis, epilepsy, transverse myelitis, and multiple sclerosis	0–7, 0–14, 0–30, and 0–60
Hypersensitivity reactions	Urticaria, angioedema, and anaphylaxis	0–7, 0–14, 0–30, and 0–60
New-onset autoimmune disease	Idiopathic thrombocytopenic purpura, diabetes, rheumatoid arthritis, hemolytic anemia, lupus, scleroderma, and mixed connective tissue disease. (Evaluation of new-onset autoimmune disease was restricted to those who had been continuously enrolled as plan members for at least 2 years)	0–7, 0–14, 0–30, and 0–60
Non-traumatic joint disease	Arthritis, arthralgia, and arthropathy	0–7, 0–14, 0–30, and 0–60
Other	Febrile illness, severe local reactions	0–7 and 0–14