Human Papillomavirus (HPV) stands as one of the most prevalent sexually transmitted infections both in Canada and globally. This virus has significant implications for public health, given its association with various cancers and the high rate of infection among sexually active individuals. According to the Public Health Agency of Canada (PHAC), approximately three-quarters of sexually active men and women will experience at least one HPV infection in their lifetime. Despite its prevalence, awareness about the broader risks associated with HPV, especially beyond cervical cancer, remains limited.
HPV is responsible for approximately five percent of all cancer cases worldwide, underscoring its impact on global health. The virus comes in over 100 strains, out of which two are primarily linked to the majority of HPV-related cancer cases. These include cancers of the cervix, vagina, vulva, penis, and anus. Notably, nearly 99 percent of all cervical cancer cases have a direct connection to HPV. Additionally, it is estimated that 25 to 35 percent of mouth and throat cancers are associated with oral HPV infection.
The National Advisory Committee on Immunization (NACI) recommends HPV vaccination for individuals between nine and 26 years of age. Vaccination is a critical preventive measure, significantly reducing the risk of developing HPV-related cancers. Data shows that receiving the HPV vaccine before the age of 17 can lead to a 90 percent reduction in invasive cervical cancer risk, while immunization before age 30 results in a 50 percent reduction.
In Canada, the vaccine is offered for free to males and females under 26 years old through school-based and catch-up programs across all provinces and territories. The Gardasil-9 vaccine, which provides protection against nine types of HPV, is available for people aged nine to 45. Furthermore, Cervarix, focusing on the two high-risk HPV types responsible for approximately 70 percent of all cervical cancer cases, is approved for women within the same age range.
For immunocompromised individuals, including those living with HIV, PHAC recommends a three-dose schedule of the Gardasil-9 vaccine. This recommendation stems from the increased vulnerability to HPV-related cancers in this population. As stated by the authors of a 2020 review, "which will result in increased burden of HPV-related cancers among [people living with HIV]." Gilles Charette emphasizes the importance of vaccination for this group, stating, "So certainly people living with HIV should be considering HPV vaccination." Shapiro further highlights, "because of the higher risk of developing certain types of HPV-associated cancers."
A point often overlooked is that even those who are already sexually active can benefit from receiving the HPV vaccine. The likelihood that an individual has been exposed to all types of HPV covered by the vaccine remains low. Therefore, vaccination can still offer substantial protection against strains they have not encountered.
Dr. Deborah Money provides reassurance regarding HPV infections:
"The good news is that, in fact for most people, it's a transient infection and it's cleared and it just goes away," – Dr. Deborah Money
Nevertheless, it is important to recognize the potential severity when the infection does not clear on its own. Money also notes the effectiveness of existing vaccines:
"They're much more effective than many of the vaccines we use," – Money
This highlights the critical role vaccines play in preventing the spread and impact of HPV.
