Study: Changing Cancer Screenings, HPV Vaccine Programs Could Save Lives, Money

December 22, 2011 - News Release

Ontario could potentially save millions of dollars and improve health by modifying its cervical cancer screening guidelines and human papillomavirus (HPV) vaccine programs, according to a new University of Guelph study.

The research by mathematics professor Chris Bauch and graduate student Stephen Tully will appear in the journal Vaccine this week and is available online now on the ScienceDirect website.

"Cervical cancer continues to impose a considerable burden worldwide,” Bauch said. In Canada, about 1,400 women are diagnosed annually.

Recent studies show HPV vaccines have proven effective in preventing the highest-risk infections, which occur in about 70 per cent of cervical cancer cases.

Currently, vaccination is provided through school-based programs for preadolescent girls. Cervical cancer screening is also recommended starting at age 18.

“The fact that there is now a vaccine that can prevent a form of cancer which affects many women is a very positive development,” Bauch said.

But universal HPV vaccine programs are among the most expensive immunization initiatives ever, prompting questions about their cost and effectiveness.

The Guelph researchers created a mathematical model to project future costs and health outcomes under a range of scenarios.

The results? To save money and improve public health, the best strategy is to extend vaccine programs by providing “catch-up” vaccinations for girls and women aged 17 to 26 who were not vaccinated under the existing program, while simultaneously delaying the start of cervical cancer screening until age 25.

This strategy would save nearly $19 million a year and reduce cancer rates enough to save 240 years of life annually.

That’s because it’s cheaper to vaccinate once than to screen repeatedly for cancer every year or so. At the same time, vaccination provides long-term protection, whereas cervical screening below the age of 25 prevents relatively few cervical cancer cases because “this age group is at lowest risk of developing cervical cancer,” Bauch said.

So, combining a delay in initial cervical cancer screenings with expanded catch-up vaccination saves significant amounts of money while also improving health, the study found.

Bauch cautioned that his mathematical model fails to account for behavioural changes. “For example, there is danger in some women thinking that, because they’ve been vaccinated, they no longer need screening. Our model does not account for that possible effect.”

As well, health-care providers often use cervical screening (Pap test) visits as an opportunity to discuss other issues such as birth control and sexually transmitted infections. “It would be important that these discussions continue to take place,” he said.

Still, mathematical models are important for policy-making, said Bauch. He has done similar studies on H1N1 mitigation strategies and on the effectiveness of voluntary vaccination.

“It is the only way to think about such issues in a quantitative way and make predictions. It provides a single platform to facilitate thinking about a problem by integrating information on its various different aspects, hence it can aid in the decision-making process.”

This latest study also involved Andrea Anonychuk of the University of Toronto and GlaxoSmithKline Biologicals in Belgium; and Diana Maria Sanchez and Alison Galvani of Yale University.

Chris Bauch
Department of Mathematics and Statistics
519-823-4120, Ext. 53079

For media questions, contact Communications and Public Affairs: Lori Bona Hunt, 519-824-4120, Ext. 53338, or, or Shiona Mackenzie, Ext. 56982, or

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