Will the HPV Vaccine Guard You?
Suzanne MacCarthy reports how Canadian HIV researchers are marching to the front lines of the fight against cervical cancer.
IF IT STARTS WITH the letter H, then I’ve either got it or will get it,” says Penelope, with a giggle. “Seriously, I know about genital herpes simplex and how common a virus it is among HIV-positive people. But the human papillomavirus (HPV) — and its potentially devastating effects — was not something I was familiar with. My doctor said that my compromised immune system made me more prone to HPV.”
Penelope, a 42-year-old Vancouver resident, has been living with HIV for 20 years. “It wasn’t until I was pregnant with my son that my doctor noticed the small bump on my genitals,” she says. “I knew it was a genital wart but I didn’t know the link between warts and HPV.” HPV infection is surprisingly common: Approximately 75 percent of Canadians harbor HPV, making it the number one sexually transmitted virus. Most people will never show any signs or symptoms, which means they may unknowingly pass on the virus.
There are more than 100 types of HPV, and about 30 of those can infect the genital tract through skin-to-skin and sexual contact. HPV types 6 and 11 cause 90 percent of genital warts; types 16 and 18 are responsible for an estimated 70 percent of cases of cervical cancer, which claims the lives of more than 400 women a year in Canada.
In women, especially HIV-positive women, HPV can lead to a range of health risks — from the benign, like Penelope’s genital warts, to life threatening, such as cervical cancer. Dr. Deborah Money, a specialist in viral pathogens in women and executive director of the Women’s Health Research Institute in Vancouver, says, “Not only are HIV-positive women the most vulnerable to HPV, they tend to have more severe viral symptoms, such as larger and harder-to-treat genital warts, than their HIV-negative counterparts.”
That’s why doctors, including Money, stress the importance for all women, HIV-positive or not, to get regular Pap tests. “A Pap test looks for abnormal cells and signs or future indications of cervical cancer,” Money says. “It’s a simple lifesaving procedure.” If caught early, cervical cancer is almost entirely preventable. For her part, Penelope follows her doctor’s advice and gets regular Pap tests. She also keeps her stress level down, gets plenty of rest and listens to her body — all of which can help bolster the immune system and prevent a recurrence of warts.
Canadians docs on guard
In 2006, another tool to help fight cervical cancer was made available to women and their doctors when Health Canada approved Gardasil — a vaccine to protect women and girls against the more common types of HPV (types 6, 11, 16 and 18). The vaccine is currently licensed for girls and women age nine to 26. “When I first heard about Gardasil, I automatically disqualified myself as a vaccination candidate,” Penelope says. “I thought it was merely a prevention strategy for young girls before becoming sexually active.”
While Gardasil is considered most effective if given before any sexual activity occurs, some experts believe that the majority of women could still benefit from the vaccine, as it’s unlikely for any one woman to have been exposed to all four types of HPV that Gardasil protects against.
However, researchers do not yet know how safe or effective the vaccine is in HIV-positive women. Given the possible serious consequences of HPV infection in women with HIV, it’s a question that HIV researchers and clinicians are keen to answer.
That answer may come soon. Dr. Money and a team of 40 researchers across Canada are leading the world’s first study to evaluate Gardasil in HIV-positive women and girls. CTN 236 is a five-year study recruiting 500 HIV-positive female participants at 16 sites across Canada over a two- to three-year period. Not only is CTN 236 breaking ground by testing the vaccine in HIV-positive women, it is also the first investigator-driven, peer-reviewed and independently funded vaccine study in which all findings of vaccine efficiency and safety will be publicly released. The study is being funded by the Canadian Institutes of Health Research (CIHR) and supported by the CIHR Canadian HIV Trials Network (CTN). Females who have HPV are eligible to participate.
When approached by her doctor about participating in the study, Penelope was enthusiastic because, she says, “This clinical trial seems crucial to all HIV-positive females.” Money echoes these thoughts, saying, “There is an urgent need to evaluate the effectiveness of the HPV vaccine in this vulnerable, high-risk group of HIV-positive girls and women in Canada. More knowledge about how HIV infection impairs the initial immune response to the vaccine and subsequent immune memory would greatly improve vaccine strategies.”
Around the world
The results of the trial may also have a global impact. In 2007, the World Health Organization (WHO) identified a knowledge gap in HPV vaccines, stating that their safety and efficiency have not yet been evaluated in Africa or in populations with a high HIV prevalence. “It’s a groundbreaking study, especially for Africa, where over half of the HIV population is female. The WHO is awaiting these trial results,” says Lisa Venables, the national project manager of CTN 236.
The study will use the same standard dosing schedule and vaccine amount currently being used in HIV-negative women and girls. The vaccine will be administered in three doses over the course of six months and trial participants will make a total of seven clinic visits in a 24-month period.
“Our results should serve to identify HIV-infected individuals who will benefit the most from this vaccine and suggest whether extra doses of the vaccine — booster shots — may be recommended in this population,” Money says. “The knowledge gained in this study will also help researchers assess the vaccine in other immunocompromised populations.”
Penelope, who at press time was awaiting her first vaccination, says that participating in a clinical trial is a necessary step in finding valuable knowledge. Referring to the possibility that being in the study could benefit herself and other women with HIV, she says, “I’ll scratch your back if you’ll scratch mine.”
To learn more about CTN 236 and other CTN trials, visit the CIHR Canadian HIV Trials Network database or call 1.800.661.4664.
Suzanne MacCarthy is Communications and Information Coordinator at the CIHR Canadian HIV Trials Network (CTN) in Vancouver. Her adventures in HIV have taken her from Swaziland to British Columbia, with a stop in beautiful Cape Breton, Nova Scotia, along the way.
How is HPV spread? The virus can pass during any form of sexual contact — oral, vaginal or anal sex, and even finger-to-genital contact. Remember: You can be infected with HPV and have no signs or symptoms. So even though you or your partner might not see any genital warts, the virus can still pass between you. Condoms reduce the risk of passing the virus but do not eliminate it because the virus may be on a part of the skin not covered by the condom.
You are at an increased risk for HPV infection if you:
• have many sexual partners
• are already infected with another sexually transmitted infection (such as chlamydia)
• have a condition that affects your immune system (such as HIV)