Incidence of cervical lesions in Danish women before and after implementation of a national HPV vaccination program
Approximately 70 % of cervical cancers and about 50 % of high-grade cervical precursor lesions are caused by human papillomavirus (HPV) types 16 and 18. Denmark introduced the quadrivalent HPV vaccine into the vaccination program for 12-year-old girls in 2009 supplemented by a first catch-up program for 13–15-year-old girls in 2008, and a second program for women up to the age of 27 years in 2012; all with high vaccination coverage. The aim of this study was to evaluate the effectiveness of the vaccine by comparing the incidence trends of cervical lesions before and after its introduction.
Incident cases of cervical lesions were identified from the nationwide Pathology Data Bank. Age-specific incidence rates were estimated for six age groups, and Poisson regression was used to calculate estimated annual percentage change (EAPC).
The incidence of atypia or worse (atypia+) and cervical intraepithelial neoplasia grade 2 or worse (CIN2+) increased in all age groups in 2000–2010. After introduction of the quadrivalent HPV vaccine into the vaccination program, the incidence of atypia+ decreased significantly in women younger than 18 years (EAPC −33.4 %; 95 % CI −49.6; −12.0) and in 18–20-year-old women (EAPC −12.6 %; 95 % CI −19.3; −5.3). The incidence of CIN2+ also decreased significantly in 18–20-year-old women (EAPC −14.8 %; 95 % CI −21.6; −7.5) in 2010–2013, but no significant decrease was seen in older age groups.
The incidence of cervical lesions decreased significantly in age groups with high HPV vaccine coverage, indicating an early effect of HPV vaccination.
KeywordsHPV Vaccination Incidence Cervical lesions Nationwide Denmark
The study was supported by the Mermaid project (MERMAID II).
Conflict of interest
Birgitte Baldur-Felskov and Christian Dehlendorff declare no potential conflicts of interest. Jette Junge received advisory board fee from Sanofi Pasteur MSD and consultant fee from Merck. Christian Munk received travel and speaker’s fees from Sanofi Pasteur MSD. Susanne K. Kjaer received advisory board and speaker’s fees and institutional research grants from Sanofi Pasteur MSD and Merck.
- 4.European Medicines Agency (2010) European public assessment report for Gardasil. http://www.emea.europa.eu/ema/index.jsp?curl=pages/medicines/human/medicines/000703/human_med_000805.jsp. Accessed Sept 2013
- 5.European Medicines Agency (2011) European public assessment report for Cervarix. http://www.ema.europa.eu/ema/index.jsp?curl=pages/medicines/human/medicines/000721/human_med_000694.jsp&mid=WC0b01ac058001d125&murl=menus/medicines/medicines.jsp. Accessed Sept 2013
- 7.Statens Serum Institut (2013) EPI-NYT: HPV-vaccination - tilslutning 2012. http://www.ssi.dk/Aktuelt/Nyhedsbreve/EPI-NYT/2013/Uge%2020%20-%202013.aspx?. Accessed Sept 2013
- 10.Kjaer SK, Munk C, Junge J, Iftner T (2013) Carcinogenic HPV prevalence and age-specific type distribution in 40,382 women with normal cervical cytology, ASCUS/LSIL, HSIL, or cervical cancer: what is the potential for prevention? Cancer Causes Control. doi: 10.1007/s10552-013-0320-z PubMedCentralGoogle Scholar
- 17.The Danish Pathology Data Bank (2011). http://www.patobank.dk/. Accessed Sept 2013
- 19.R Development Core Team (2012) R: a language and environment for statistical computing. Auckland: R Foundation for Statistical Computing. Vienna, Austria. ISBN 3-900051-07-0. http://www.R-project.org. Accessed Oct 2013
- 20.Harrell FE Jr (2013) rms: Regression modeling strategies. R package version 3.6-3. http://cran.r-project.org/web/packages/rms/index.html. Accessed Oct 2013
- 32.Statens Serum Institut (2013) Indberetning og patient registrering: Patologi. http://www.ssi.dk/Sundhedsdataogit/Indberetning%20og%20patientregistrering/SEI/Patologi.aspx. Accessed Nov 2013
- 33.Danske Regioner (2012) Økonomisk vejledning 2008, 2010, 2011 and 2012. http://www.regioner.dk/økonomi/økonomisk+vejledning/baggrundsmappe2007og2008/regionernes+bidrag+til+patobanken+i+2008. Accessed Nov 2013Google Scholar