Gardasil, a Good Idea?
Gardasil is a HPV vaccine produced by Merck. HPV, Human Papilloma Virus, has clearly been demonstrated to increase the risk of a woman developing cervical cancer so it would seem to be a good idea to provide young woman, even as teenagers, with a vaccine that would guard against the virus and prevent the development of invasive cervical cancers which would otherwise be produced by the virus.
In 2006 Merck Pharmaceuticals received the go ahead. The FDA approved the distribution of Gardasil, a Human Papilloma Virus vaccine manufactured by Merck Pharmaceuticals and Merck promptly began the distribution of the vaccine.
Later in the same month the distribution began, the advisory committee on immunization practices recommended routine vaccination of girls 11 to 12 years old. Remarkably, these recommendations were issued before completion of the so-called phase III trials demonstrating whether advanced pre-cancerous lesions of the cervix are prevented by the use of the vaccine.
In fact, only two of the fifteen types of HPV known to have a cancer-producing potential have been shown to be affected by the vaccine.
Merck has seen to it that the public has been provided with a favorable view of the vaccine. In a report by Rothman and Rothman published in the Journal of the American Medical Association this year, Marketing HPV vaccine: implications for adolescent health and medical professionalism, JAMA 2009 Aug 19; 302(7):781-786 the author shows how Merck employed the assistance of various important medical associations by providing the associations with ready-made presentation slide sets, emails and letters to promote the product. All this publicity in favor of the use of the vaccine began before important trials had even been concluded.
Now, in the same issue of the Journal of the American Medical Association in which the report of Rothman and Rothman appears, there is an article from the U.S. Centers for Disease Control and Prevention and the U.S. Food and Drug Administration reporting adverse events occurring in the two and a half years following administration of Gardasil, Postlicensure Safety Surveillance for Quadrivalent Human Papillomavirus Recombinant Vaccine, Slade, B.A., Leidel, L.,Vellozzi, C.; et al. JAMA 2009 Aug 19; 302(7): 750-757. There were 752 adverse reports. 6.2% of the adverse reports involved serious adverse effects, including 32 reports of death but the system of depending on voluntary reports of adverse events risks underreporting and there is no real evidence that the adverse events reported resulted from the vaccine. Such adverse events reports are based solely on an event occurring after the administration of the vaccine and not because of any other evidence proving the vaccine caused the event.
So, we don’t really know the extent of any benefit a young woman will receive as a consequence of being vaccinated and we also don’t know the risk.
What a nightmare for a parent with a decision to make about a teenager receiving Gardasil. Cervical cancer continues to kill thousands of women every year. If the leading cause of the cancer is a virus that can be prevented by vaccination, how does one decide to not offer the vaccination? If, as some have suggested, the chances are less than six adverse events per thousand doses distributed and only 6.2% of those represent serious adverse effects, that means that one serious adverse event would be associated with every three thousand doses distributed. But even with a risk this small, has there been a sufficient benefit demonstrated to justify that risk?
In a completely different context, many years ago Jonas Salk pointed out to me the importance of focusing on the numerator. If the chance is 1 in 10,000,000 and you are the one, it is little comfort that 9,999,999 other doses were administered safely.
Perhaps it was easier long ago when we knew little and simply did what we were told. If not better, perhaps it was just a lot simpler. What do you think?