Background and aim
The aim of the project is to investigate the effect of HPV vaccination in Norway on pre-stages to cancer and cervical cancer. HPV vaccine that protects against the HPV types that cause most cases of pre-stages to cancer and cervical cancer has been available since 2007. Birth cohorts with a high coverage rate of the vaccine are approaching the age at which pre-stages to cancer and cervical cancer can occur. We will investigate whether HPV vaccination begins to have a protective effect in the population. This is very important knowledge from a public health perspective. The study focuses on the vaccine type Gardasil, which was given in the childhood vaccination program in the period 2009-2016.
In addition, we will monitor the incidence of pre-stages to cancer and cancer of the vulva and vagina, as these also are related to HPV-infection.
This is a register-based study at the population level. All information used in the study is routinely collected by public health registries, and the study therefore does not require active participation from the women included in the study.
The total study population is all women living in Norway as of January 1st in each calendar year 2004-2023. Information about dates and results from cell samples, diagnostics and treatment is collected from the Cancer Registry. The Norwegian Prescription Database and the National Vaccination Registry (SYSVAK) collect data related to HPV vaccination, such as when the vaccine was prescribed/taken and which vaccine was involved. MSIS collects information about any diagnoses of sexually transmitted infections. The social security number makes it possible to collect and link data between the registries.
The project data received from each registry will be pseudonymized, i.e. without a name, social security number etc., which makes it impossible to directly identify individuals. The data file will only contain the minimum number of variables needed to address the aim of the study, and date variables will not be more accurate than month and year. This minimizes the chance of so-called indirect identification. Results from the study will be presented at the overall level. The analyses will be performed on the Cancer Registry’s secure server, and all project members are subject to a duty of confidentiality. The Regional Committee for Medical and Health Research Ethics (REK) give ethical assessment and legal approval for the execution of the project.
Collection of data from the registries is complete. Analysis is ongoing.