Prevalence of human papillomavirus (HPV) among the population
Background and purpose
The first approved HPV vaccine that protects against high-risk types HPV 16 and HPV 18 known to cause cervical cancer, and also HPV 6 and HPV 11 that cause genital warts, was approved for use in 2006.
This study has provided important information about all 40 HPV types that infect the cervical mucosa. The study was implemented in the population before the HPV vaccine became available, and provides an opportunity to detect any changes in the incidence of HPV after the introduction of the HPV vaccine.
The project was part of a Scandinavian collaboration, focusing on mapping HPV types in Scandinavia. The biological material consists of surplus material from Pap samples taken in connection with the cervical screening programme, and this has been collected from 6000 Norwegian women. The women included in the study have all received information about the study and been informed about the option to opt out.
Findings
In 2006-2007, the survey was implemented in Norway, Iceland, Denmark and Sweden. We detected a very high incidence, 25.7% of HPV among women aged 18 to 50 years in Norway in the time period before HPV vaccination. The highest prevalence of HPV was in the age group 18-23 years, where just over half of the women were positive for HPV, 57%. Also, among women aged 24-26 years, the HPV positivity rate was very high 47.1%. In general, the incidence of HPV decreased with increasing age, with an incidence of 12.6% for women aged 40-50 years. HPV 16 was the HPV type associated with the highest risk of high-grade cytology, of which 11.2% had high-grade cell changes.
In 2012, we conducted the survey again in Norway, Sweden and Denmark. Among 18-26-year-old women, the proportion of HPV positives was highest in Norway. Compared with 2006, the proportion of HPV6,11,16 and 18 positives decreased by 4% in Norway. For Norwegian women between 27-50 years, we found no change in the same period. The results have also been combined with corresponding data from Sweden and Denmark to describe the prevalence of HPV types in Scandinavia. The total incidence of HPV in Scandinavia decreased slightly from 36.5% in 2006-2008 to 34.5% in 2012-2013. The decline was most marked and statistically significant for women between 18-26 years (from 54.4% to 48.1%).
For those who participated in the study
Thank you for your contribution!
Your test results are linked to data from the Cancer Registry, the National Vaccine Registry and a questionnaire survey on women's lifestyle and health (as described in the information letter). The Regional Committees for Medical and Health Research Ethics (REK) have approved extending the study period to 31.12.2030. The collected samples will now also be used to test new methods that can be used in the follow-up of HPV-positive people in screening. You can read more about this project here.
In addition, data from the study are used to investigate possibilities for more personalised screening against cervical cancer (see here).
If you do not wish to participate in our research, you can register in the Register for Biological Research Reservation
If you would like further information, please contact project manager Mari Nygård .
Publications
Dillner J, Nygård M, Munk C, Hortlund M, Hansen BT, Lagheden C, Liaw KL, Kjaer SK (2018)
Decline of HPV infections in Scandinavian cervical screening populations after introduction of HPV vaccination programs
Vaccine, 36(26), 3820-3829
doi 10.1016/j.vaccine.2018.05.019, PubMed 29778519
Nygård M, Hansen BT, Kjaer SK, Hortlund M, Tryggvadóttir L, Munk C, Lagheden C, Sigurdardottir LG, Campbell S, Liaw KL, Dillner J (2020)
Human papillomavirus genotype-specific risks for cervical intraepithelial lesions
Hum Vaccin Immunother
doi 10.1080 /21645515.2020.1814097, PubMed 32990181
