Twelve and 13-year-old girls and boys are eligible to receive the HPV vaccine, delivered in two doses six months apart, which protects against nine types of HPV.

HPV causes about 90 per cent of cervical cancers in women and 95 per cent of HPV-related cancers in men.

With the start of the school year, Cancer Council Victoria has urged all parents of year sevens to sign the vaccine consent form to ensure their children are protected.

"It is fantastic that lots of Ballarat parents are choosing to protect their children, but there is still work to be done to ensure that all teens have the opportunity to complete the free vaccine course and protect themselves against cancer-causing HPV," said Cancer Council Victoria screening, early detection and immunisation manager Kate Broun.

Figures from the Australian Institute of Health and Welfare show 86 per cent of Ballarat girls received the vaccine in 2015-2016, among the top five immunisation rates across the state, but only 75 per cent of boys.

"The vaccine is most effective when given at age 12-13. Two injections are needed, with the second dose administered 6-12 months after the first. We are urging parents to sign the vaccine consent form and ensure their teen receives both doses for the best protection against cancer," Ms Broun said.

The introduction of the HPV vaccination program in 2007 has seen a 93 per cent drop in cases of the two most serious HPV types, and a 70 per cent fall in pre-cancerous cervical abnormalities in women under 20, a 50 per cent reduction in women aged 20-24 years, and a 20 per cent drop for women aged 25 to 29.

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In a study published today by the Medical Journal of Australia, researchers said HPV was found in 93 per cent of cervical cancers using standard laboratory methods, highlighting the importance of the HPV vaccination and HPV-based screening programs.

"HPV vaccination and HPV-based screening offer effective methods of preventing most cervical cancers," wrote lead researcher Associate Professor Julia Brotherton from the VCS Foundation.

"Ongoing monitoring of the proportion of cervical cancers associated with HPV should continue, with the expectation that the absolute rate of HPV-associated cancer will fall over time and the absolute rate of HPV-negative cancers will remain stable, resulting in an increase in the relative proportion of HPV-negative cancers," they concluded.

"This will be an indicator of the success of our cervical cancer prevention programs."

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