Table 3:

Autoimmune disorders diagnosed after quadrivalent human papillomavirus vaccination

Variable	Cases/person-time		Rate ratio (95% CI)
	Exposed	Unexposed	Unadjusted*	Adjusted†
HPV4 vaccine (overall)	77/99 841	604/825 160	0.86 (0.67–1.10)	1.12 (0.85–1.47)
History of immune-mediated diseases
Yes	41/54 247	326/446 732	0.84 (0.61–1.18)‡	1.11 (0.72–1.62)‡
No	36/45 567	278/378 428	0.87 (0.61–1.24)‡	1.12 (0.75–1.67)‡

Note: CI = confidence interval, HPV = human papillomavirus, HPV4 = quadrivalent HPV.

^*Unadjusted rate ratios were derived from self-matched models that implicitly controlled for time-fixed confounders and only included the HPV vaccine (exposure).

^†Adjusted for age at diagnosis, seasonality (Table 2), receipt of non-HPV vaccines (7–60 d before diagnosis) and recent infection (7–60 d before diagnosis), and implicitly adjusted for time-fixed confounders through the use of a self-matched analysis.

^‡p = 0.4 for a 2-sided test of interaction comparing those with and without a history of immune-mediated diseases at a significance threshold of α = 0.05.