A little info on Gardasil:
From Wikipedia, the free encyclopedia
See also: HPV vaccine
Gardasil (Merck & Co.), also known as Gardisil or Silgard,[1][2] is a vaccine approved June 8, 2006 by the U.S. Food and Drug Administration (FDA) for use in the prevention of certain types of human papillomavirus (HPV),[3] specifically HPV types 6, 11, 16 and 18.[4][5] HPV types 16 and 18 cause an estimated 70% of cervical cancers,[6][7] and are responsible for most HPV-induced anal,[8] vulvar, vaginal,[9] and penile cancer cases. HPV types 6 and 11 cause an estimated 90% of genital wartscases.
Gardasil has been used in prevention of two types of HPV infections, associated with approximately 70% of HPV cases.[citation needed] It does not treat existing infection. Therefore, to be effective it must be given before HPV infection occurs. The HPV strains that Gardasil protects against are sexually transmitted, and HPV-16 has a 60% per-couple transmission rate.[10]
The U.S. Food and Drug Administration (FDA) recommends vaccination before adolescence and potential sexual activity.[11][12][4]
Development history
The research that led to the development of the vaccine began in the 1980s by groups at the University of Rochester, Georgetown University, and the US National Cancer Institute (NCI). In 1991, Australian investigators at The University of Queenslandfound a way to form non-infectious virus-like particles (VLP), which could also strongly activate the immune system. However, these VLPs assembled poorly and did not have the same structure as infectious HPV. In 1993, a laboratory at the US National Cancer Institute was able to generate HPV16 VLPs that were morphologically correct. These VLPs were the basis for the HPV16 component of the Gardasil vaccine.[13] Upon commercialization of the vaccine, controversy involving intellectual property arose between the various groups that played a role in developing the vaccine.
[edit]Clinical trials
Merck & Co. conducted a Phase III study named Females United to Unilaterally Reduce Endo/Ectocervical Disease (FUTURE II). This clinical trial was a randomized double-blind study with one controlled placebo group and one vaccination group. Over 12,000 women aged 16–26 from thirteen countries participated in the study. Each woman was injected with either Gardasil or a placebo on day 1, month 2, and month 6. In total, 6,082 women were given Gardasil and 6,075 received the placebo.[14] Subjects in the vaccine group had a significantly lower occurrence of high-grade cervical intraepithelial neoplasia related to HPV-16 or HPV-18 than did those in the placebo group.[14] On February 27, 2006, the independent Data and Safety Monitoring Board recommended the clinical trials be terminated on ethical grounds, so that young women on placebo could receive Gardasil.[15]Merck tested the vaccine in several hundred 11- and 12-year-old girls.[16]
[edit]Indications and prevalence
Main article: HPV vaccine#Prevalence of genital HPV
Gardasil is a prophylactic HPV vaccine, meaning that it is designed to prevent HPV infections. For maximum effect, it is recommended that girls receive the vaccine prior to becoming sexually active. However, women who were already infected with one or more of the four HPV types targeted by the vaccine (6, 11, 16, or 18) were protected from clinical disease caused by the remaining HPV types in the vaccine.
Since Gardasil will not block infection with all of the HPV types that can cause cervical cancer, the vaccine should not be considered a substitute for routine pap smears.
Fewer HPV infections mean fewer complications from the virus and less time and money spent on the detection, work-up, and treatment of cervical cancer and its precursor, cervical dysplasia. It prevents infertility caused by cervical biopsies and reduces the severe respiratory problems of children who are infected by HPV from their mothers.
In addition, protection against HPV 6 and HPV 11 is expected to eliminate 90% of the cases of genital warts. Gardasil also protects against vulvar and vaginal cancers caused by HPV types 16 and 18.[9]
In December 2010, Gardasil was approved by the FDA for prevention of anal cancer and associated precancerous lesions due to human papillomavirus (HPV) types 6, 11, 16, and 18 in people ages 9 through 26 years.[17][18]
HPV infections, especially HPV 16, contribute to some head and neck cancer (HPV is found in an estimated 26-35% of head and neck squamous cell carcinoma).[19] In principle, HPV vaccines may help reduce incidence of such cancers caused by HPV, but this has not been demonstrated.[20]
Merck was denied FDA approval to market Gardasil to women aged 27 to 45. Although it was found to be safe and effective in the prevention of genital warts, it was not effective in the prevention of cervical cancer in that age group. [21]
[edit]Use in males
Gardasil is also effective in males, providing protection against genital warts, anal cancer, and some potentially precancerous lesions caused by some HPV types.[5][22][23][18] An ongoing study of 4,065 males demonstrated the efficacy of Gardasil in males who did not have HPV infection prior to vaccination.[8] The vaccination is expected to protect against penile cancer and anal cancer caused by included HPV types, and research in this area is still[when?] underway.[8]
In December 2008, Merck asked the U.S. Food and Drug Administration (FDA) for permission to market the vaccine in the United States for males between ages 9 to 26,[24] and the FDA approved the request on October 16, 2009.[5][25][26][27][28][29] In the UK, HPV vaccines are already[when?]licensed for males aged 9 to 15 and for females aged 9 to 26.[30]
Gardasil is in particular demand among gay men, who are at significantly increased risk for genital warts and anal cancer caused by HPV.[31]
A 2005 study in San Francisco, California found that 95% of HIV-infected gay men also had anal HPV infection, of which 50% had precancerous HPV-caused lesions.[32]
Type 16 is also associated with oropharyngeal squamous-cell carcinoma, a form of throat cancer.[33]
[edit]Administration
Gardasil is given in three 0.5 milliliter injections over six months. The second injection is two months after the first, and the third injection is four months after the second shot was administered.[4][11]
[edit]Ingredients
Proteins of HPV Types 6, 11, 16, and 18
amorphous aluminum hydroxyphosphate sulfate (adjuvant)
yeast protein
sodium chloride
L-histidine
polysorbate 80
sodium borate[11][34]
[edit]Biotechnology
The HPV major capsid protein, L1, can spontaneously self-assemble into virus-like particles (VLPs) that resemble authentic HPV virions. Gardasil contains recombinant VLPs assembled from the L1 proteins of HPV types 6, 11, 16 and 18. Since VLPs lack the viral DNA, they cannot induce cancer. They do, however, trigger an antibody response that protects vaccine recipients from becoming infected with the HPV types represented in the vaccine. The L1 proteins are produced by separate fermentations in recombinant Saccharomyces cerevisiae and self-assembled into VLPs.[11]
[edit]Efficacy
The National Cancer Institute says, "Studies have shown that both Gardasil and Cervarix prevent nearly 100 percent of the precancerous cervical cell changes caused by the types of HPV targeted by the vaccine for up to 4 years after vaccination among women who were not infected at the time of vaccination."[35] The vaccine is believed to be effective for longer, but for how long, and whether a booster shot will be needed is still being studied.[citation needed]
Gardasil has been shown to be partially effective (approximately 38%) in preventing cervical cancer caused by ten other high-risk HPV types.[36]
[edit]Safety
As of February 2009, 40 million doses of Gardasil had been distributed worldwide.[37] The vaccine was tested in thousands of females (ages 9 to 26).[38] The Food and Drug Administration (FDA) and the Centers for Disease Control and Prevention (CDC) consider the vaccine to be safe. It does not contain mercury, thiomersal or live virus or dead virus, only virus-like particles, which cannot reproduce in the human body.[38]
The FDA and the CDC say that the vaccine has only minor side effects, such as soreness around the injection area.[38] Fainting is more common among adolescents receiving the Gardasil vaccine than in other kinds of vaccinations. Patients should remain seated for 15 minutes after they receive the HPV vaccine.[34] There have been reports that the shot is more painful than other common vaccines, and the manufacturer Merck partly attributes this to the virus-like particles within the vaccine.[39] General side effects of the shot may include joint and muscle pain, fatigue, physical weakness and general malaise.[34][40]
An update on adverse events was published by the Journal of the American Medical Association and looked at data from the Vaccine Adverse Event Reporting System (VAERS), covering 12,424 reported adverse events after about 23 million doses of vaccine between June 2006 and December 2008.[41][42] Most adverse effects were minor and not greater than background rates compared with other vaccines, the exception being higher rates for syncope and venous thromboembolic events.[42] Venous thromboembolic events were noted in 56 reports at a rate of 0.2 cases per 100,000 doses distributed and included 19 cases of pulmonary embolism, four of which were fatal.[42] Overall, 772 events (6.2% of the total number of adverse events, but only 0.003% of the total number of doses) were described as serious and included 32 deaths (1 per 1,000,000 doses).[42]
Other adverse events include local site reactions (7.5 cases per 100,000 doses distributed), headaches (4.1 cases per 100,000 doses distributed), hypersensitivity reactions (3.1 cases per 100,000 doses distributed), and urticaria (hives) (2.6 cases per 100,000 doses distributed).[42]
The FDA and the CDC said that with millions of vaccinations "by chance alone some serious adverse effects and deaths" will occur in the time period following vaccination, but have nothing to do with the vaccine.[43] More than 20 women who received the Gardasil vaccine have died, but these deaths have not been causally connected to the shot.[43] Where information has been available, the cause of death was explained by other factors.[44][45] Likewise, a small number of cases of Guillain-Barré Syndrome (GBS) have been reported following vaccination with Gardasil, there is no evidence linking GBS to the vaccine.[12][46][41] It is unknown why a person contracts GBS, or what initiates the disease.[47]
The FDA and the CDC monitor events to see if there are patterns, or more serious events than would be expected from chance alone.[44] The majority (68%) of side effects data were reported by the manufacturer, but in about 90% of the manufacturer reported events, no follow-up information was given that would be useful to investigate the event further.[42] In February 2009, the Spanish ministry of health suspended use of one batch of Gardasil after health authorities in the Valencia region reported that two girls had become ill after receiving the injection. Merck has stated that there was no evidence Gardasil was responsible for the two illnesses.[37]
[edit]Public health advantages
Main article: HPV Vaccine
The National Cancer Institute writes:
Widespread vaccination has the potential to reduce cervical cancer deaths around the world by as much as two-thirds, if all women were to take the vaccine and if protection turns out to be long-term. In addition, the vaccines can reduce the need for medical care, biopsies, and invasive procedures associated with the follow-up from abnormal Pap tests, thus helping to reduce health care costs and anxieties related to abnormal Pap tests and follow-up procedures.[35]
[edit]Long-term impact and cost-effectiveness
One unknown property of the vaccines now being researched is the persistence of their protective effects. Since the Gardasil vaccine has been administered for only a few years now, it is unknown whether it will provide life-long immunity to recipients. In coming decades, further study will answer this question.
Whether the effects are temporary or life-long, widespread vaccination could have a substantial public health impact. 270,000 women died of cervical cancer worldwide in 2002.[48] Acting FDA Administrator Dr. Andrew von Eschenbach said the vaccine will have "a dramatic effect" on the health of women around the world.[49] Even in the United States, where screening programs are routine, the National Cancer Institute estimated that 9,700 women would develop cervical cancer in 2006, and 3,700 would die.[50]
Merck and CSL Limited are expected to market Gardasil as a cancer vaccine, rather than an STD vaccine. It remains unclear how widespread the use of the three-shot series will be, in part because of its $360 list price ($120 each for three shots).
Since both men and women are carriers of HPV, vaccination of males could provide greater herd immunity.[51]
Studies using different pharmacoeconomic models predict that vaccinating young women with Gardasil in combination with screening programs may be more cost effective than screening alone.[52] These results have been important in decisions by many countries to start vaccination programs.[53] For example, the Canadian government approved $300 million to buy the HPV vaccine in 2008 after deciding from studies that the vaccine would be cost-effective especially by immunizing young women.[54] Marc Steben, an investigator for the vaccine, wrote that the financial burden of HPV related cancers on the Canadian people was already $300 million per year in 2005, so the vaccine could reduce this burden and be cost-effective.[55]
Since penile and anal cancers are much less common than cervical cancer, HPV vaccination of young men is likely to be much less cost-effective than for young women.[43]
Diane Harper, one of the lead researchers for Gardasil, has called for more complete warnings for parents and questions its risk-versus-benefit profile because it is not yet known how long the vaccine will be effective once administered.[56] The August 2009 issue of the Journal of the American Medical Association had an article reiterating the safety of Gardasil[41] and another questioning the way it was presented to doctors and parents.
The new vaccine against 4 types of human papillomavirus (HPV), Gardasil, like other immunizations appears to be a cost-effective intervention with the potential to enhance both adolescent health and the quality of their adult lives. However, the messages and the methods by which the vaccine was marketed present important challenges to physician practice and medical professionalism. By making the vaccine's target disease cervical cancer, the sexual transmission of HPV was minimized, the threat of cervical cancer to adolescents was maximized, and the subpopulations most at risk practically ignored. The vaccine manufacturer also provided educational grants to professional medical associations (PMAs) concerned with adolescent and women's health and oncology. The funding encouraged many PMAs to create educational programs and product-specific speakers' bureaus to promote vaccine use. However, much of the material did not address the full complexity of the issues surrounding the vaccine and did not provide balanced recommendations on risks and benefits. As important and appropriate as it is for PMAs to advocate for vaccination as a public good, their recommendations must be consistent with appropriate and cost-effective use.[57]
In an address at the 4th International Public Conference on Vaccination sponsored by the anti-vaccination group the National Vaccine Information Center in October 2009, Dr. Diane Harper stated that in countries where Pap smear screening is common, it will take vaccination of a large proportion of women in order to further reduce cervical cancer rates. She also stated that no efficacy trials for children under 15 have been performed.[56][58]
Medical groups,[specify] politicians[specify] and parents began rebelling after disclosure of a behind-the-scenes lobbying campaign by Gardasil's maker, Merck & Co., to get state legislatures to require 11- and 12-year-old girls to get the three-dose vaccine as a requirement for school attendance.[citation needed]
Objections from doctors and parents groups were due to the vaccine protecting against a sexually transmitted disease, human papilloma virus, which causes cervical cancer. They cited that vaccines mandated are typically for diseases spread through casual contact, such as measles and mumps.
On February 20, 2007, Merck announced its immediate suspension of this campaign, which had been funded through a third party.[59]
The governor of Texas, Rick Perry, issued an executive order adding Gardasil to the states required vaccination list which was later overturned by the Texas legislature. Perry has also allowed parents to more easily opt-out of the program. Through lobbying efforts, Merck has suggested that governments make vaccination with Gardasil mandatory for school attendance, which has upset some conservative groups and libertarian groups.[49][60][61] Conservative groups, including the Family Research Council (FRC), have expressed fear that vaccination with Gardasil might give girls a false sense of security regarding sex and lead to promiscuity.[49][61][62][63]
During the Republican Party presidential debate on September 12, 2011, candidates Representative Michelle Bachmann and former Senator Rick Santorum criticized fellow candidate Governor Rick Perry for his executive order.[64] The following day, on the NBC Today Show Bachmann said “I will tell you that I had a mother last night come up to me here in Tampa, Fla., after the debate and tell me that her little daughter took that vaccine, that injection, and she suffered from mental retardation thereafter".[65] In response, Merck rejected claims that Gardasil causes mental retardation and stated this side effect has never been reported for this vaccine.[66] The comment may have resulted from confusion over the thimerosal controversy, in which similar claims have been made for other vaccines, but Gardasil does not contain thimerosal.[67]
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