Human papillomavirus vaccination and Pap testing profile in Manitoba, Canada

Females who receive the human papillomavirus (HPV) vaccine may believe they are protected from developing cervical cancer and no longer require screening. Concern has also been expressed that vaccinated females are those that would be screened regularly. This study assesses the Pap testing behavior of vaccinated and non-vaccinated females.

For this population-based retrospective cohort study, vaccination and screening registries were linked for 3540 vaccinated females aged 15 years and over and 9592 matched non-vaccinated females. Conditional logistic regression, the Kaplan-Meier method and Cox regression were used to examine the association between vaccination and Pap testing.

Vaccinated females were more likely to have had a Pap test within the year prior to the index date than non-vaccinated females (15-19 years old: OR=1.38, 95% CI 1.20-1.59; 20+ years old: OR=2.34, 95% CI 1.98-2.76). In the three-year period after the index date, vaccinated females had a significantly higher cumulative probability of having a Pap test (83.3%) than non-vaccinated females (66.1%). Females who had a Pap test within three years prior to the index date were more likely to have a Pap test after the index date (vaccinated: HR=5.03, 95% CI 4.65-5.45; non-vaccinated HR=3.97, 95% CI 3.70-4.24). Being vaccinated had a significant effect on Pap testing (15-19 years old: HR=1.54, 95% CI 1.39-1.69; 20+ years old: HR=1.87, 95% CI 1.52-2.31). 80.1% of vaccinated females who had a Pap test prior to the index date also had one subsequent to it, compared to 70.1% for non-vaccinated females. 41.1% of females had not been vaccinated nor had a Pap test.

The majority of vaccinated females continue to participate in screening, and do so at a higher rate than non-vaccinated females. Renewed efforts need to be made to include the large proportion of non-vaccinated, non-screened females in vaccination and/or screening.