Autoimmune disorders diagnosed after quadrivalent human papillomavirus vaccination, stratified by time since vaccination
| Exposure risk window, d* | No. of exposed cases | Rate ratio (95% CI) | p value§ | |
|---|---|---|---|---|
| Unadjusted† | Adjusted‡ | |||
| 7–24 | 22 | 0.87 (0.49–1.11) | 0.95 (0.61–1.48) | 0.1 0.2 |
| 25–42 | 40 | 1.38 (0.74–1.42) | 1.31 (0.93–1.84) | |
| 43–60 | 15 | 0.73 (0.44–1.42) | 0.97 (0.57–1.66) | |
Note: CI = confidence interval, HPV = human papillomavirus, HPV4 = quadrivalent HPV.
↵* The duration of time following each dose of the HPV4 vaccine during which the occurrence of an event is attributable to the effects of the vaccine.
↵† 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 value for 2-sided test of interaction between risk windows using a significance threshold of α = 0.05.