Human papillomavirus vaccination and subsequent cervical cancer screening in a large integrated healthcare system.

BACKGROUND

Human papillomavirus vaccination may result in lowered intention to be screened for cervical cancer, potentially leading to gaps in screening coverage and avoidable cervical cancer diagnoses.

OBJECTIVE

The purpose of this study was to examine the association between human papillomavirus vaccination and subsequent cervical cancer screening initiation and adherence to recommended screening intervals to detect gaps in screening coverage and inform future prevention efforts.

STUDY DESIGN

A retrospective cohort study was conducted in 2 distinct cohorts of female members of Kaiser Permanente Southern California, which is a large integrated healthcare delivery system. Papanicolaou screening initiation was evaluated in women who reached 21 years from 2010-2013. Adherence to recommended screening intervals was evaluated in women who were 25-30 years old in 2010. All women were observed to the end of 2013 for the evaluation of their screening behaviors. History of human papillomavirus vaccination and Papanicolaou screening were obtained from electronic medical records. Adherence to recommended screening intervals was measured as ≥85% vs <85% of the observed "screening up-to-date" person-time. Multivariable Cox and logistic regression models were used to examine associations between vaccination history and screening initiation and interval adherence. Demographic characteristics, gynecologic health history, healthcare use, and characteristics of women's primary care providers were included as potential confounders in the analyses.

RESULTS

There were 27,352 and 41,328 women included in the screening initiation and screening interval adherence analyses, respectively. In comparison with unvaccinated women, adjusted hazard ratios (95% confidence intervals [CIs]) for screening initiation among women who had been vaccinated against human papillomavirus were 1.19 (95% CI, 1.11-1.28), 1.44 (95% CI, 1.34-1.53), and 1.57 (95% CI, 1.50-1.65) for 1, 2, and ≥3 doses, respectively. Adjusted odds ratios for screening interval adherence were 0.93 (95% CI, 0.83-1.04), 1.73 (95% CI, 1.52-1.97), and 2.29 (95% CI, 2.05-2.56), for 1, 2, and ≥3 doses, respectively.

CONCLUSION

Women who had been vaccinated against human papillomavirus in this community-based, integrated healthcare setting were more likely to be screened for cervical cancer than were unvaccinated women. Our findings underscore the need for targeted interventions among unvaccinated women who may be disproportionally affected by cervical cancer, despite the presence of population-based screening programs.