A 7.5-year prospective study of longer than 18 months type-specific human papillomavirus persistence in a routine cytology-based cervical screening population of about 31,000 women in West Germany.

The objective of this study was to analyse the prevalence, infection pattern, duration and outcome of long-term, type-specific, persistent human papillomavirus (HPV) infections in a routine cytology-based cervical screening population of West German women followed up for 7.5 years. From a screening population of 31,000 women, a strictly selected cohort of 100 patients with > or =18-month persistent, type-specific HPV infection were prospectively followed up for a mean of 35.52 months (+/-13.0). HPV type prevalence and odds ratios for regression, progression and steady state were analysed, as well as the influence of age and HPV coinfection on outcome. Altogether, 21 different genotypes were detected. Seventy-two percent of women were infected with high-risk HPVs, 24% with low-risk and 4% with unknown risk HPV types; 44% of cases had coinfections with multiple HPV types. The risk of progression in low-grade squamous intraepithelial lesions and high-grade squamous intraepithelial lesions was the highest for infections with high-risk HPVs [odds ratio: 2.2 (0.79-6.11, 95% confidence interval)], whereas cases with low-risk and unknown risk HPVs tended to regress or remained unchanged during follow-up. The mean duration of infections showed considerable variation among the different HPV types and risk groups detected and ranged between 19.7 and 54.3 months. Age was not significantly associated with disease progression and infection duration, and histology had a poor sensitivity for detecting high-grade dysplasia. In conclusion, detecting long-term persistent HPV infections by genotyping may help to identify women with cervical intraepithelial lesions who are at lower and higher risk of developing high-grade precancer and cancer. This may influence future screening strategies and therapy decisions.