Most of you are probably aware of the common sexually transmitted infections chlamydia and gonorrhea. Of course, knowing how to protect yourself against these bacteria is extremely important for anyone who is sexually active (hint: use a condom!). Unfortunately, HPV is not talked about nearly as frequently and is not quite as simple, despite being by far the most common STI.
HPV stands for Human Papilloma Virus, and there are over 100 different circulating strains.1 Of these, we know that 40 can infect the genital tract, with exposure occurring during vaginal, anal, oral, or digital sex (i.e., finger penetration). Although a condom lowers the chance of transmission, HPV can be spread through exposed skin that is not covered by a condom.2 A 2016 systematic review found that it may even be spread by sharing sex toys, or theoretically by coming into contact with infected surfaces at the gym or locker room (yuck!).3 It comes as no surprise then, that most sexually active people have been exposed to HPV at one time or another, with an estimated 75% of sexually active Canadians infected at least once in their lifetime.
The good news is that the majority of HPV strains are harmless, usually asymptomatic, and most people will clear the infection on their own within 1-2 years like any other common virus.4 In fact, most people who have been infected with HPV would never know it. Some strains, while low-risk for causing cancerous changes, can lead to genital warts that can be emotionally distressing and difficult to remove. Other strains classified as high risk are more likely cause changes in cellular structure, called dysplasia, that have the potential to turn into cancer.
Almost all (99%) of cervical cancers (and some types of vaginal, vulvar, and anal cancers) can be traced back to infection with these high-risk HPV strains, which is why regular pap screening is so important.1,4 Pap tests detect precancerous cellular changes at the cervix before they become dangerous, and rates of cervical cancer have declined greatly since pap screening became widespread in the 1970s. During a pap test, the cervix is visualized with a speculum and a thin layer of cells is scraped off to check for cellular dysplasia, or abnormal cervical cells. These cells are then graded according to how advanced the changes are, which directs your physician on what to do next. This may be more as simple as more frequent monitoring with repeat pap tests until you have had several successive normal pap tests, or referral to a colposcopy clinic where cervical cells are looked at more closely under a special microscope.
Most high-risk HPV infections will be fought off by the immune system without progressing into cancer. For example, the most common high-risk subtype, HPV 16, is cleared by the body within 16 months on average, according to an Advisory Committee Statement by the Public Health Agency of Canada.1 This is the reason why pap testing is only recommended once every 3 years in Ontario, as most infections will clear on their own within this time. If we increased the frequency of screening pap tests, we would pick up more cellular changes that would have gone away on their own within the testing period. This timeline saves individuals from repeated invasive testing like colposcopy (looking at the cervix up close through a microscope) and biopsy (taking a small sample of cervical tissue for testing) that would ultimately be unnecessary, because these cellular changes would have never progressed into cervical cancer.
Conversely, the vast majority of cervical cancer is slow growing, taking a decade or more to develop.1 This slow growth means that persistent changes in the cervical cells that are not being cleared by the body can be caught and managed safely within the 3-year screening period to prevent the development of invasive cancer. A new type of testing that looks directly for the HPV virus in cells, rather than testing for cellular changes caused by HPV, has shown promise in further improving the accuracy of detecting cervical precancer and has already been implemented in several countries.4 If HPV testing is adopted in Canada as part of regular screening, cervical testing may only be required once every 5 years instead of once every 3 years provided results are normal. The research for this adoption is up and coming, and policy changes for cervical cancer screening guidelines in Ontario will likely change in the next 5-10 years.
So what can be done to protect against HPV and cervical cancer? The absolute best thing that you can do to protect yourself is to GET VACCINATED as well as to ensure you are receiving regular pap tests by your primary care provider according to the Ontario screening guidelines. Again, condoms reduce the risk of transmission, but cannot completely prevent it.
Vaccination with Gardasil 9 protects against the 9 HPV strains that cause 90% of cervical cancers and the 2 HPV strains that cause 90% of genital warts.5 The peak risk for HPV exposure is in the first 5 years of sexual activity, which is why this vaccination is offered to children in Grades 6-8 in Ontario (ideally before the first time you have sex).6 This program was recently expanded to include boys as well as girls as a result of growing evidence that HPV infection rates are similar between adolescent males and females. In addition to lowering rates of transmission to sexual partners, vaccination of males protects them from genital warts and some HPV-related cancers such as anal and penile cancer.1 Vaccination is currently recommended for women until the age of 45 and men until the age of 25, and may be covered or partially covered by university or private drug plans.
Screening for cervical cancer begins at age 21 or at the age of first sexual activity, whichever is later, and occurs once every 3 years thereafter if cervical cells look normal. These guidelines are the same for women who have sex with women and transgendered men who have a cervix, and do not change if you have been vaccinated.7
The good news is that while HPV infection is common, there are easy and effective measures that can be taken to protect yourself from genital warts and cervical cancer. Cervical cancer is now one of the least common cancers affecting women, thanks to regular pap tests! If you don’t have a family doctor you see regularly, visit Queen’s Student Health on campus to get screened and discuss options for vaccination today. Your cervix will thank you for it!
Celine Conforti, BScH, MD Candidate at McMaster University
Sarah Saliba, BScH, MD Candidate at McMaster University
Public Health Agency of Canada. National Advisory Committee on Immunization. (2007). Canada Communicable Disease Report: Statement on human papillomavirus vaccine (Volume 33, ACS-2). Ottawa ON: Desktop Publishing.
U.S. Department of Health. Centre for Disease Control and Prevention. (2017). Genital HPV infection – fact sheet. Retreived from https://www.cdc.gov/std/hpv/stdfact-hpv.htm
Liu, Z., Rashid, T., & Nyitray, A. G. (2016). Penises not required: a systematic review of the potential for human papillomavirus horizontal transmission that is non-sexual or does not include penile penetration. Sex Health, 13(1), 10-21.
National Cancer Institute. (2014). Pap and HPV testing. Retreived from https://www.cancer.gov/types/cervical/pap-hpv-testing-fact-sheet#q1
Merck Canada. (2018). Protection against HPV-related cancers and genital warts. Retrieved from https://www.gardasil9.ca
Government of Canada. Canadian Immunization Guide: Part 4 – Active Vaccines. (2018). Human papillomavirus vaccine. Retreived from https://www.canada.ca/en/public-health/services/publications/healthy-living/canadian-immunization-guide-part-4-active-vaccines/page-9-human-papillomavirus-vaccine.html
Cancer Care Ontario. (2017). Screening guidelines – Cervical cancer. Retreived from https://archive.cancercare.on.ca/pcs/screening/cervscreening/screening_guidelines/