Two articles in the New England Journal of Medicine (NEJM) are raising more concerns about the cervical cancer vaccines, Gardasil and Cervarix. The first, an editorial, questions the widespread use of Gardasil and Ceravix, despite a lack of evidence about their effectiveness. The second article, a study that looked at the high cost of the vaccines, concludes that Gardasil and Cevarix are only cost effective if they are used in specific ways.
Gardasil, Merck & Co.’s vaccine, was approved by the Food & Drug Administration (FDA) in June 2006. At the time of its approval, Merck said that clinical trials had proven the vaccine to be between 90-100% effective in preventing the transmission of some strains of the Human Papillomavirus (HPV) that cause cervical cancer. Shortly after its approval, the Centers for Disease Control (CDC) issued a recommendation that all young girls between the ages of 11 and 12 receive the Gardasil vaccine.
Cevarix, made by GlaxoSmithKline, has not been approved by the FDA yet, but is widely used in Europe.
In the NEJM editorial, Dr. Charlotte J. Haug writes, “Despite great expectations and promising results of clinical trials, we still lack sufficient evidence of an effective vaccine against cervical cancer.” Dr. Haug contends that the uncertainty surrounding the vaccines provides reason to be cautious.
According to the editorial, Gardasil and Cevarix were studied in clinical trails for at most six and a half years. It is still not known how long the immunity will last, or whether eliminating some strains of HPV will decrease the body’s own immunity to other strains.
The other NEJM article details a Harvard analysis that explored the cost effectiveness of the vaccines. Both Gardasil and Cevarix are given as a series of three injections, and can cost as much as $1,000 to complete. In Western countries, like the U.S. and Great Britain, regular screening via Pap tests has already greatly reduced incidences of cervical cancer and deaths. But even after vaccination, regular Pap tests are necessary because the shots don’t protect against all HPV strains known to cause the cancer.
To measure the health benefit of vaccination, the researchers looked at the cost savings from preventing cervical cancer with the vaccine and Pap tests compared with prevention via the tests alone. A treatment is typically considered cost effective if it is less than $50,000 or $100,000 for one additional year of life
The Harvard analysis predicted that it would $43,600 to extend life expectancy by one year when girls are vaccinated at 12. When girls up to age 18 are included in the analysis, that ratio rises to $97,300 and to $153,000 through age 26, the study found. That’s because vaccination is less effective after a woman is sexually active, and may have already been exposed to HPV.
However, the analysis assumed that Gardasil and Cevarix will be effective for life – something that is as of now unknown – and that women get regular screenings to detect the first signs of cervical cancer. If the vaccine’s protection against HPV stops after 10 years, the cost of vaccinating preteen girls would more than triple to $144,100 per year of life gained, the study said. In those case, the researchers said that cervical cancer prevention through Pap testing alone would make more sense from a cost standpoint.
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