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About

What is the IMPACT Study?

The National HPV Monitoring Program (also called IMPACT) was established in 2014 to develop and implement an ongoing surveillance system that monitors the prevalence of HPV infection in the Australian population over time. The Program provides a central mechanism for evaluating the impact of the National HPV Vaccination Program on HPV infection.

As there is a lead time of decades between initial HPV infection and the ultimate adverse outcome of cancer, monitoring HPV infection provides an efficient means of monitoring vaccine program impact in the short- to medium-term.

The Program forms a core component of Australia’s National HPV Surveillance Strategy and is funded by the Commonwealth Department of Health.

What is the National HPV Vaccination Program?

HPV is a very common sexually transmitted virus that infects both men and women. Cancers caused by some types of HPV include cancer of the cervix (in women), the penis (in men), as well as in the anus and certain types of throat cancer in both women and men. Infection with HPV types that cause the majority of these cancers can be prevented through vaccination. There are three (bivalent, quadrivalent and nonavalent) commercially available HPV vaccines. All protect against the oncogenic HPV types 16 and 18, which cause 70% of cervical cancers, and most other anogenital cancers. The nonavalent vaccine targets five additional oncogenic types which account for a further 20% of cervical cancers. The quadrivalent and nonavalent vaccines also protect against HPV 6 and 11, which cause most genital warts.

Australia in 2007 implemented a National HPV Vaccination Program targeting females aged 12–13 years through schools with three doses of the quadrivalent HPV vaccine. A community based, catch-up program was offered to women up to the age of 26 years until 2009. In 2013, the vaccination program was extended to include 12–13 year old males, with a catch up for males 14–15 years of age through 2015. In 2018, the next nonavalent HPV vaccine in a routine two-dose schedule replaced the three-dose schedule of quadrivalent vaccine in the program.

In 2019, all females and males older than 15 and up to the ages of 38 and 21 respectively, have been eligible for vaccination in the National HPV Vaccination Program. See Figure 1 below.

What are the program objectives?

IMPACT aims are:

  1. To monitor long term prevalence of HPV infection among women participating in the renewed National Cervical Screening Program;
  2. To monitor HPV prevalence among young women not eligible for cervical screening
  3. To monitor long term prevalence of HPV infection among men who have sex with men

What methodology is used in the Program?

IMPACT has used multiple mechanism for monitoring HPV infection prevalence.

Between 2014 and 2018 the Program utilised a consent-based mechanism to target priority populations aged 18–35 years for HPV testing at health services across Australia, as well as through the social networking site Facebook. Consenting participants were asked to self-collect a sample for HPV testing and complete a short demographic questionnaire. Information on HPV vaccination histories was obtained from the National HPV Vaccination Register. During that time 4,789 participants were recruited, and analyses of these data are ongoing. Key findings published to date can be found here.

In 2019 the Program methodology was revised, and now draws on two mechanism of data collection. These include:

  1. Analyses of data routinely reported to the National Cancer Screening Register, to obtain national level information on HPV infection prevalence among women participating in cervical screening.
  2. HPV testing of residual samples collected through a network of laboratories to monitor HPV infection prevalence among women who are not yet eligible for cervical screening (i.e. under the age of 25 years) and men who have sex with men.

Where available, data on basis socio-demographic factors routinely reported are also collected, in addition to information on HPV vaccination histories.

What are the program outcomes??

The data collected will be reported against key indicators for monitoring HPV vaccine impact outlined in the National Strategy. These include, monitoring prevalence of vaccine-preventable and non-vaccine targeted HPV types over time, by age cohort, vaccination status, Indigenous status, geographical area and socioeconomic status.