Colposcopic performance in a birth cohort previously eligible for human papillomavirus vaccination

Sweden started subsidized quadrivalent human papillomavirus vaccination for girls aged 13 to 17 in 2007. Since 2012, vaccination has been offered to all girls aged 10 to 12 within a school-based vaccination program, with a coverage of 80% or more. In addition, the vaccine has been offered on-demand as catch-up vaccination for girls aged 13 to 18, with a cumulative coverage of 55% to 60%. Since the first women in Sweden eligible for human papillomavirus vaccination entered the cervical screening program, questions on how to evaluate colposcopic findings among vaccinated women have arisen. Evidence is inconsistent on whether colposcopic features for the detection of cervical lesions are influenced by specific human papillomavirus genotypes and what role they can play in the prevention of invasive cervical cancer in vaccinated women.

The primary objective of the study was to compare colposcopic evaluation in vaccinated and unvaccinated women entering the organized cervical screening program.

Women in the 1994 and 1995 birth cohorts who entered the cervical screening program at age 23 in 1 region in Sweden were identified. Colposcopy was performed within 2 to 4 months after a positive screening result in accordance with national guidelines. Colposcopic performance was evaluated according to national guidelines with the Swede score and colposcopic impression. Punch biopsies were taken from colposcopic lesions and as "random biopsies" in the absence of lesions. These biopsies were used as the gold standard for the analysis. An endocervical sample was analyzed for cytologic findings and detection of 14 high-risk human papillomavirus genotypes. All colposcopic imaging was saved digitally for re-review. Vaccination status was obtained through linkage to national vaccination registries. Results were compared between vaccinated and unvaccinated women.

In 2018 and 2019, 160 out of 165 (98%) women with a positive screening result attended colposcopy, of which 90 (56%) were vaccinated and 70 (44%) were unvaccinated. Only 7 out of 90 (5%) women in the vaccinated group were human papillomavirus 16/18-positive, compared with 23 out of 70 (33%) in the unvaccinated group (P<.001). There was a total of 61 out of 160 (38%) women with high-grade lesions-33 out of 90 (37%) in the vaccinated group and 28 out of 70 (40%) in the unvaccinated group (P=.697). There was 64% (21/33) of vaccinated women and 75% (21/28) of unvaccinated women with high-grade squamous intraepithelial lesions who had a Swede score of 6 to 10 (indicating high-grade squamous intraepithelial lesions) (P=.124). The sensitivity was slightly higher for the detection of high-grade squamous intraepithelial lesions in unvaccinated women using both colposcopic tests (Swede score, 0.67 vs 0.75; colposcopic impression, 0.67 vs 0.68), but the difference was not statistically significant.

We found no statistically significant difference between the colposcopic evaluation of vaccinated and unvaccinated women, although human papillomavirus vaccination reduced the prevalence of human papillomavirus 16/18 infection in human papillomavirus-vaccinated women. Our results indicate that colposcopic examination is still a useful tool in vaccinated women entering the organized cervical screening program.