Sexually transmitted infections

Calculating the impact of the HPV vaccine

(NC)-Each year in Canada, approximately 400 women die of cervical cancer and another 1,400 are diagnosed with the disease. But that is about to change.

In 2006, Health Canada approved a vaccine that protects against four strains of human papillomavirus (HPV) that are responsible for causing 70% of cervical cancer cases. Soon after, provincial governments began introducing HPV immunization programs. Will the new vaccine really be as effective as many hope? How long will it take for cervical cancer rates to come down?

New vaccines always bring hope, but the success of a vaccine depends on many factors, such as the number of people who decide to get vaccinated. Early numbers suggest that vaccine uptake has varied widely from province to province. With the help of funding from the Canadian Institutes of Health Research (CIHR), Dr. Christopher Bauch at the University of Guelph, his students and co-investigators are constructing a computer model that could help us anticipate the changes that will come with the HPV vaccine.

"The vaccine will reduce the number of cases of cervical cancer, but we're not sure how large the reduction will be or how quickly it will happen." says Bauch. "We can't predict the future, but computer models can help us project what might happen."

Public health officials will be able to use Bauch's model to estimate how cervical cancer rates will change and which women will benefit most from the immunization campaigns. The result is reduced health-care costs and more targeted treatment.

For example, if a large number of women decide to roll up their sleeves for the HPV vaccine, this could help change screening recommendations for cervical cancer. Currently, Health Canada recommends that women have a Pap smear every three years (or more frequently if they have specific risk factors) to help catch the disease in its early stages.

"If the vaccine reduces the incidence of cervical cancer by a large percentage, it might be sufficient for most women to be screened every five years. Then we could take the money that we save on screening and use it to create outreach programs for women who are less likely to be screened or who have a particularly high risk of developing cervical cancer," explains Bauch.

Bauch emphasizes that, for now, it is very important that all women continue to follow the current screening recommendations. But with the help of his research, we may be able to look forward to a future without cervical cancer.

Courtesy News Canada