Dr. Nancy Durand, FRCS, Gynaecologist
bh IN BRIEF
The first vaccine for Human Papilloma Virus (HPV) was released a year ago. In coming years, the targeted population will expand to include older women and boys. Federal funding of $300 million will have limited impact. Private drug plans often cover vaccines, and employers will be wrestling with the significant potential cost, the limited public funding, and the strong scientific evidence that these vaccines will prevent most cases of cervical cancer and genital warts.
Dr. Nancy Durand, a specialist in HPV and abnormal pap tests, speaks to the controversy surrounding the vaccine, the larger but lesser-known health issue beyond cervical cancer, and her sense of the value these products bring to Canadian women.
Q: Who should take the current HPV vaccine (Gardasil)? With another competitor coming to market soon, is this target likely to change?
Right now, Gardasil is approved for use in females age 9-26 for the prevention of cervical, vulvar and vaginal cancers, and genital warts, a much more common condition. It has already been approved for girls and boys in several countries.
Cervarix is the only other HPV vaccine. It is exclusively targeted at cancer and Canadian approval is expected soon.
Research is beginning to look at vaccination for HPV in men, and anal cancer for both genders. A clinical trial for older women will finish soon, and while the vaccine likely won't be as effective for this group, they will still want it. The Boomer mentality will ensure demand, and there are many related viruses that may cause cancer.
Q: What are the risks and benefits of HPV vaccines?
First, I really believe that uncertainty about the vaccine has been driven by journalism, not by the science or by doubt among those who are well informed.
The number of serious adverse effects, such as Guillain-Barre Syndrome (GBS), fainting, and death, has been very small. There have been 7 million doses of Gardasil given in the US. The number of cases of GBS reported in the vaccinated group is 13, which is lower than expected. Although there were seven deaths in the vaccinated group, extensive investigation by the US Centers for Disease Control has not found these events to be attributable to vaccination. They were more closely tied to other drugs taken, or to lifestyle.
The common side effects – sore red arm, fever, nausea, and gastro-intestinal symptoms – are generally mild and transient, and occur at the same frequency with placebo. I personally believe the vaccine is safe, and have vaccinated my own children.
The benefit of vaccination is huge if given before sexual activity begins. The current vaccine protects against strains 16 and 18, which cover 70% of all cervical cancers, as well as against types 6 and 11, which cause 90% of external genital warts. There may also be some cross-protection with other strains.
Q: How are these vaccines administered?
On a physician order, pharmacists will dispense the vaccine but it must be administered by a doctor or nurse, except in Alberta where pharmacists can also inject. Clinics and some physicians will carry a stock in their own clinics for safety and convenience. The vaccine must be refrigerated, and has a shelf life of about one year. The 3-dose vaccination schedule for both products would be today, then in one or two months, with the final dose six months later.
Q: How confident are you that patients will comply/adhere to the schedule of three injections?
It is very important for physicians or others to track patients and persistently follow up. Adherence is very important; all three doses are needed to get the full benefit. As the market gets bigger, and it will, special vaccination clinics may be staged at pharmacies, by public health departments or by Nurse Practitioners.
Q: Most HPV infections clear themselves, and cervical cancer is relatively rare. With such a broad indication, and a cost of about $500 per patient, is it worth it? If so, for whom?
One of the key issues for patients and payers is the place of prevention. I think the area of vaccines and the emphasis on preventing illness will only grow: the first approved indication will not be the last.
The cost of lost work, worry and distraction is hard to quantify, but it is not small. In Canada, there are about 1,400 cases of invasive cancer each year, but there are around 400,000 cases involving pre-cancerous cells, HPV, and genital warts. When a woman gets one of these diagnoses, there will be two, three, or more visits to her family doctor and specialist, at a minimum of a half day each, plus treatments.
Given the long payback from vaccination, I hope the government will extend and broaden their financial support.
Categories: Doctor On Call