High-throughput monitoring of human papillomavirus type distribution.

BACKGROUND There is a need for a rapid and cost-effective evaluation of the effects of different human papillomavirus (HPV) vaccination strategies. Sexually active adolescents are a preferred target group for monitoring, as effects on HPV prevalence would be measurable shortly after implementation of vaccination programs. METHODS The Swedish Chlamydia trachomatis testing program offers free Chlamydia trachomatis testing and reaches a majority of all adolescents in the population. We anonymized the 44,146 samples submitted for Chlamydia trachomatis testing in Southern Sweden during March to November 2008 and conducted HPV genotyping using PCR followed by mass spectrometry. RESULTS The HPV positivity peaked at 54.4% [95% confidence interval (CI), 52.2-56.6] among 21-year-old women and at 15.0% (95% CI, 12.4-17.6) among 23-year-old men. The HPV positivity was 37.8% (95% CI, 37.3-38.3) for women and 11.2% (95% CI, 10.6-11.8) for men. The most prevalent types among women were HPV 16 (10.0%; 95% CI, 9.7-10.3) and HPV 51 (6.0%; 95% CI, 5.7-6.3) and, among men, HPV 16 (2.1%; 95% CI, 1.8-2.4) and HPV 6 and HPV 51 (1.7%; 95% CI, 1.5-1.9). CONCLUSION The high HPV prevalences seen in the Chlamydia trachomatis screening population enables monitoring of the HPV type distribution among sexually active adolescents at high precision. IMPACT Effectiveness of HPV vaccination programs in terms of reducing HPV infections has been difficult to measure because of logistic constraints. We describe a system for high-throughput monitoring of HPV type-specific prevalences using samples from the Chlamydia trachomatis screening program.