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. Some of these can cause anal and genital warts and others can lead to more serious consequences such as cervical, penile and anal cancers. Other types of HPV can cause certain cancers of the head and neck.

As HPV is one of the most common sexually transmitted infections it is estimated that the majority of sexually active Canadians will have a sexually transmitted HPV infection at some point in their lives. It is estimated that more than 70 per cent of sexually active Canadian men and women 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. 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 lessen 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 from all sexual activities offers protection against sexually transmitted infections. Immunization prior to sexual debut is effective in protecting against most sexually transmitted HPV infections.

There are now two HPV vaccines authorized for use in Canada, Gardasil^® and Cervarix^®. Gardasil^® provides protection against four HPV types, two that cause 70 per cent of all cervical cancers and two that cause 90 per cent of all genital and anal warts. It is approved for use in females and males aged 9 to 26. Cervarix^®, a vaccine that protects against the two HPV types that cause 70 per cent of all cervical cancers, has recently been approved for use in Canada for females aged 10 to 25. 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 vaccines currently available do 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 disease prevention. The Public Health Agency of Canada (PHAC) supports sexual health education and programs to prevent 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 STIs 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 use in Canada. The Public Health Agency of Canada supports two committees that make recommendations on the use of vaccines in Canada.

The National Advisory Committee on Immunization (NACI) is a national scientific advisory 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 reviews the evidence on a number of factors, including which groups in Canada are most at risk for contracting a given vaccine-preventable disease, and makes evidence-based recommendations on who should receive the vaccine.

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. 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.

NACI and CIC are currently reviewing the current recommendations in light of the approval of Cervarix^® and the expanded use of Gardasil^® for boys and young men. To learn more about the Canadian drug and health technology regulatory process (led by Health Canada), including information on HPV, please follow the links on the left-hand menu.

In addition to the advice provided to the provinces and territories, the Government of Canada also provided $300 million to provinces and territories over three years to establish HPV immunization programs before March 31, 2010, as part of Budget 2006.

Surveillance and Monitoring

PHAC continues to monitor adverse events following immunization related to HPV and updates the information routinely. PHAC will also monitor the uptake of HPV vaccine across the country through the bi-annual National Immunization Coverage Surveys for routine childhood immunizations, the first cycle of the survey to include HPV immunization will be in 2011.

HPV is not a nationally notifiable disease in Canada. Nevertheless, PHAC is already carrying out studies to assess the prevalence of the virus and the incidence of HPV types associated with cancer. PHAC is also working with the provinces and territories to look at options to use sentinel sites and registry-based data to link vaccine uptake with disease outcomes. This will mean that data on HPV infections, disease outcomes and vaccine uptake will be collected in specific areas across the country and those figures can then extrapolated to get a picture of the overall rate of infection in Canada and in at-risk groups.

For example, as part of the International Polar Year, PHAC researchers were funded to complete 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. Other large HPV prevalence studies in the Canadian Arctic include Nunavut, Labrador and the Yukon. In addition, PHAC supported studies have been conducted, or are in progress, in Manitoba and the Atlantic provinces. A population based survey of HPV prevalence is being conducted in collaboration with Statistics Canada.

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.

Scientists at PHAC's National Microbiology Lab (NML) have developed a rapid test that can identify which of more than 40 different types of HPV a patient could be infected with. This test is being used in number of Canadian and international studies on HPV prevalence.

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.