Despite growing safety concerns about Gardasil, the Food & Drug Administration (FDA) approved it to prevent two more cancers. Gardasil targets four strains of the human papillomavirus (HPV) that cause most cases of cervical cancer. Two of those HPV strains can also cause some vulvar and vaginal cancers.
Gardasil was approved by the 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. Since the CDC recommendation, Merck has been aggressively marketing Gardasil. In at least 24 states, the company is trying to convince state legislatures to make Gardasil mandatory for young girls.
Not everyone has been so enthusiastic about Gardasil, mainly over safety concerns. There have been 9,749 adverse reactions following Gardasil and 21 reported deaths since 2006. Those side effects, which were reported to the Vaccine Adverse Event Reporting System (VAERS) included 10 miscarriages, 78 severe outbreaks of genital warts and six cases of Guillain-Barré syndrome, an autoimmune disorder that can result in paralysis.
Gardasil may also cause more allergic reactions than other vaccines. Earlier this month, Australian researchers at the Children’s Hospital at Westmead are reported that young women in that country who received Gardasil to prevent cervical cancer were five to 20 times more likely to suffer a rare and severe allergic reaction – anaphylaxis – versus other girls who received other vaccines in comparable school-based vaccination programs.
It is also not known how long the immunity from Gardasil lasts, and whether eliminating some strains of HPV will decrease the body’s own immunity to other strains. Finally, others have questioned the cost effectiveness of the expensive injections.
Still, the FDA has approved new language for the Gardasil label that states the vaccine also protects against cancers of the vagina and vulva, which affect more than 5,000 women in the U.S. each year. It was not immediately clear what the additional indication would mean for sales of the vaccine, which have fallen short of the company expectations, partly because of safety worries.
According to Forbes.com, Merck has already scaled back full-year sales estimates for Gardasil from between $1.9 billion and $2.1 billion to between $1.4 billion and $1.6 billion.