Human Papillomavirus (HPV)

Human Papillomavirus (HPV) can infect different parts of the body. There are over 100 types of HPV. Some types of HPV are primarily sexually transmitted and can cause anal and genital warts and others lead to more serious consequences such as cervical, penile and anal cancers. There is a link between HPV and certain cancers of the head and neck.

It is estimated that 75 per cent of sexually active Canadians will have a sexually transmitted HPV infection at some point in their lives. Most HPV infections occur without any symptoms and go away without treatment over the course of a few years. However, in some people, HPV infections can persist. This is especially dangerous if the persistent infection is a cancer-causing type. Persistent HPV infection with a cancer-causing type is the major cause of cervical cancer.

• Prevention
• Immunization Recommendations
• Surveillance and Monitoring

Prevention

Fortunately, there are precautions that can be taken to reduce the risk of contracting HPV. The virus is spread through skin-to-skin contact, so transmission can be reduced through safer sex practices including the consistent and proper use of condoms as well as a reduction in the number of sexual partners. Abstinence is also an option to prevent HPV infection.

Additionally, there is an HPV vaccine, Gardasil® authorized for use in Canada among girls and women 9-26 years old in Canada. This vaccine provides protection against two HPV strains that cause 70 per cent of all cervical cancers as well as two HPV strains that cause 90 per cent of all genital and anal warts.

Early detection is crucial to identifying cancerous and pre-cancerous cells, and can vastly improve a woman's treatment options and survival rate should she be diagnosed with cervical cancer or its precursors. The HPV vaccine currently available does not protect against all cancer-causing types of HPV, so all women, including those who have been immunized, should continue to undergo regular cervical cancer screening (i.e. Pap tests).

Education is a key component of any public health intervention which involves health related decision making. The Public Health Agency of Canada (PHAC) supports sexual health education and the prevention of sexually transmitted infections (STI), including HPV. PHAC has developed comprehensive resource materials for educators and public health professionals that address their information needs surrounding HPV. In collaboration with stakeholders, PHAC is developing information materials for health care professionals and youth, including diagnostic and treatment guidelines for STI and a STI pamphlet for youth to increase awareness of the risk factors and the symptoms of STIs, including HPV.

Immunization Recommendations

All drugs in Canada, including vaccines, undergo stringent analysis by the drug regulator, Health Canada before they are authorized for sale. The Public Health Agency of Canada supports two committees that make recommendations on the use of vaccines in Canada.

The National Advisory Council on Immunization (NACI) is a national committee of recognized experts in the fields of pediatrics, infectious diseases, immunology, medical microbiology, internal medicine and public health, and it makes recommendations for the use of vaccines currently or newly authorized for sale in Canada. NACI completes an epidemiological analysis to determine which groups in Canada are most at risk for contracting a given vaccine-preventable disease, and determines who should receive the vaccine based on these risk factors.

The Canadian Immunization Committee (CIC) is a committee made up of federal, provincial and territorial health authorities and was established to provide advice and recommendations on the implementation of the National Immunization Strategy and immunization program planning, as well as other issues impacting immunization.

While NACI assesses the vaccine characteristics and the burden of disease and provides recommendations on which groups stand to benefit from vaccine protection, the CIC assesses other factors that might affect program delivery such as:

• Program options and strategies to benefit the population;
• Population-based cost-benefit analysis;
• How the recommended immunization schedule aligns with other recommended vaccines;
• Acceptability of the vaccine, by parents as well as by those who are eligible to receive the vaccine.

Both committees were formed in order to give provincial/territorial health authorities the information they need to make informed decisions about immunization programs in their jurisdictions. In Budget 2006, the Government of Canada provided $300 million until 2010 to provinces/territories to establish HPV immunization programs. The recommendations of both NACI and the CIC on the HPV vaccine help to ensure that each jurisdiction uses these funds in the most effective way to provide as much protection as possible for their citizens. To review the recommendations that NACI and CIC have made regarding HPV, and to learn more about the Canadian drug and health technology regulatory process (led by Health Canada) please follow the links on the left-hand menu.

Surveillance and Monitoring

HPV is not a nationally notifiable disease in Canada. Nevertheless PHAC is already carrying out studies on the national prevalence of the virus, and the incidence of strain types associated with cancer. PHAC is also in the process of implementing HPV surveillance using registry-based and/or sentinel site approaches across Canada. This means that extensive data on HPV infections is collected in specific areas across the country and those figures can then be extrapolated to get a picture of the overall rate of infection in Canada, particularly in at-risk groups.

For example, as part of the International Polar Year http://pm.gc.ca/eng/media.asp?id=1840, PHAC researchers were funded to completed a study on the prevalence of type specific HPV infection and cervical dysplasia (precancerous cells) in women of the Northwest Territories to inform the planning and implementation of more effective cancer screening programs in the area.

PHAC also maintains the pan-Canadian Cervical Cancer Prevention and Control Network, which is made up of representatives from provinces, territories and clinical professional bodies, and aims to:

• Ensure the evidence needed to assess HPV vaccine implications for screening is gathered
• Undertake inclusive, pan-Canadian recommendation-development processes concerning screening in the HPV vaccine arena

In addition to PHAC's screening and surveillance activities, scientists at PHAC's National Microbiology Lab (NML) are also working to gain an understanding of the prevalence of the more dangerous cancer-causing strains of sexually transmitted HPV. The Viral Sexually Transmitted Disease (STD) Lab at the NML has developed a rapid test that can identify which of more than 40 different strains of HPV a patient could be infected with, and can also detect infections with multiple strain types. Research is ongoing into using this test to enhance traditional PAP testing and identify patients that have active infections with the more dangerous HPV strains early on, before a pre-cancerous stage develops.

In addition, NML is collaborating with health authorities both within Canada and internationally to identify which types of HPV are circulating. PHAC officials are also developing, in collaboration with the Canadian Public Health Laboratory Network, a national proficiency program for HPV testing in Canada, which will help health practitioners decide when HPV testing is necessary and will identify best practices in HPV testing.