By Brandel France de Bravo, MPH, Maushami DeSoto, Ph.D., and Krystle Seu
Q: What do I need to know about HPV?
A: Human Papilloma Virus (HPV) is the name for a group of viruses that cause cervical cancer, genital warts and several other diseases. There are more than 120 different types of HPV. Many of them are spread through sexual contact and affect the genital areas of men and women. Although most types of HPV do not increase the risk of cancer, some types spread through sexual contact can cause cancers in male or female genitals, the anus, or the throat area. In fact, two types-HPV 16 and HPV 18-are responsible for approximately 70% of all cases of cervical cancer. You should also know that HPV infections are usually asymptomatic, meaning people who are infected don’t even realize they have the virus. Most of the time HPV infections clear up by themselves the same way a person with a cold virus gets better with time. Nine out of ten people are “over” their HPV, regardless of the type, in less than two years.
Q: What is this HPV vaccine, Gardasil?
A: Gardasil is the first vaccine ever sold in the U.S. to prevent cancer: cervical cancer. It was approved by the FDA in June 2006 for use among girls and women between the ages of 9 and 26. It helps protect them from 4 of the more than 120 types of HPV. It provides protection against HPV 6 and HPV 11, which cause 90% of genital warts, and against HPV 16 and HPV 18, which are responsible for 70% of cervical cancer cases. In addition to protecting girls and women who were never before exposed to HPV, it can also protect a sexually active girl or woman who was previously exposed to HPV from getting re-infected. If a girl or woman is actively infected with HPV at the time of vaccination, however, the vaccine would not protect her against cervical cancer. The vaccine does not protect against most of the other types of HPV that cause 30% of cervical cancers, and it can’t be used to “cure” or treat an active HPV infection. This is why it’s so important that women who are sexually active get regular PAP smears (every 3 years) starting at age 21. Pap smears are able to detect cervical cancer in its early stages when treatment is most effective.
Q: How long does the vaccine’s protection last?
A: According to Gardasil’s Web site (www.gardasil.com), it has not been established exactly how long the vaccine’s protection lasts. Gardasil is still very new, and because cancers can take years to develop it will be many years before we know conclusively how effective the vaccine is in providing lifelong protection against cervical cancer. However, studies of antibodies of vaccinated girls and women have shown that the vaccine’s protection against HPV 18-one of the two types of HPV that cause cervical cancer-may wear off for many girls and women in as little as 3 years. Uncertainty about the duration of the vaccine’s protection on top of the high cost (about $400-$1,000 for all three doses) should make you think twice about rushing out to get it.
Q: You’re saying that the protection may not last more than a few years. Is there a booster shot to make it last longer?
A: The manufacturer of Gardasil, Merck, has not publicly stated that a booster shot is needed, but in their key study for the FDA, the company gave a booster shot to all the girls and women after 60 months (5 years)-just a week before they tested their antibodies and concluded that the vaccine provided protection after 5 years! Even in the study, Merck didn’t call this additional shot a booster shot, but rather a “challenge dose”-as if they were trying to confuse anyone reading the study results. And it worked. Most health officials are not aware that the vaccine apparently requires a booster.
Even worse, the company did not compare women who got this extra (booster) dose to those who didn’t. As a result, nobody knows how long the vaccine lasts without a booster. And the company has not published any research to show how long the booster lasts either. Is it one year, 3 years, 5 years, 10 years? There is no public information about it.
Q: How much does the vaccine cost?
A: Gardasil is the most expensive vaccine to have ever been recommended for school-age children. The vaccine manufacturer charges $120 for each dose (not counting the doctor’s fee), and the total cost per patient for the initial 3-shot regimen ranges from $400-$1,000. If the HPV vaccine is mandated in your state and you can not afford to pay for it, the cost will be covered by the Federal Government which provides the vaccine to clinics and health providers that participate in the Vaccines for Children program. The high cost of the vaccine and the unknowns about the cost and frequency of booster shots raise serious concerns about mandating the vaccine for 12 year olds.
Q: What’s the best age to get vaccinated with Gardasil?
A: Because the vaccine’s protection against HPV 18 can wear off in as little as three years, a girl vaccinated at 12 could lose her protection against cervical cancer just when she is most likely to become sexually active-at 15 or 16.
Health officials have recommended that girls get vaccinated at age 12 based on Merck’s conclusion that Gardasil is not effective against current (active) HPV infections, and therefore is most effective for girls who are not yet sexually active. But the company’s own research shows that the vaccine is as effective or more effective among girls and women with previous (not active) HPV infections as among young girls who have never been exposed to HPV through sex. This is good news because older girls and women with past exposure to HPV are clearly sexually active and therefore are more in need of the protection that Gardasil provides. New research from France also supports this: a French researcher recently presented results of a study on 17,000 women and found that Gardasil prevented cervical lesions among women with previous HPV exposure at nearly the same rate as it did among women with no previous HPV exposure.
This new research means that the only girls or women who would not benefit from Gardasil are those that have current, active infections at the time that they are vaccinated. From a cost-effectiveness point of view, even if the vaccine is effective for a few years, it is probably better to wait until a girl or women is sexually active before vaccinating her, instead of vaccinating 12-year olds. But, unless a booster lasts a very long time, it will be very expensive to keep getting vaccinated, no matter how old a girl or woman is when she is first vaccinated.
Q: What are the side effects and risks of Gardasil?
A: As of August 2008, more than 20 million doses of Gardasil had been distributed in the U.S. and there were 10,326 reports registered through the CDC’s Vaccine Adverse Event Reporting System (VAERS). Minor side effects, such as pain or tenderness at the injection site, are quite common. The most common side-effect observed since Gardasil became available to the public is fainting after receiving the vaccine, which is being dealt with by warning health providers to keep patients under observation for 15 minutes after giving the shot.
Serious but rare side effects such as Guillain-Barré Syndrome (GBS), which causes muscle weakness, have been reported. According to the CDC, cases of GBS following administration of Gardasil do not represent a statistically significant increased risk, even though 9 of the 13 reported cases of GBS occurred during a biologically plausible time frame, meaning that the vaccine could plausibly be the cause. A few girls who were vaccinated with Gardasil have died, but it is not known if the vaccine is the cause.
More research is needed to determine if girls or women vaccinated with Gardasil are at an increased risk for GBS or other serious side effects.
Like any medical product, a vaccine’s risks must be weighed against its benefits. This is why it is so important to determine how long the vaccine lasts and how well it works. Since the vaccine is so expensive, if it provides only a few years protection, almost any risk becomes unacceptable.
Q: Does anyone else make a more effective or less expensive HPV vaccine?
A: Cervarix, made by Glaxo Smith Kline, has been approved for use in at least 66 countries in Europe and Australia. It is not yet approved for use in this country because the Food and Drug Administration (FDA) asked for longer-term studies of Cervarix than it required of Gardasil. Published studies suggest that Cervarix may provide protection against the two viruses that cause most cervical cancer (HPV 18 and 16) for at least 6.4 years. The FDA will not approve Cervarix until the necessary studies are completed, and we won’t know much about the studies until FDA reviews them. Comparisons of the two vaccines would enable policy makers to make better-informed decisions, and the availability of a second, competing HPV vaccine might help make vaccinating against HPV more affordable.
Q: What are other ways of preventing HPV?
A: Cervical cancer can be prevented with routine cervical cancer screening (Pap smears) and follow-up of abnormal results. The Pap test can identify abnormal or pre-cancerous changes in the cervix so that they can be removed before cancer develops. Even if you have been vaccinated with Gardasil, you have to get regular Pap screening because the vaccine doesn’t protect against all the types of HPV that can cause cervical cancer.
HPV is spread by skin to skin contact. Sexual intercourse is not necessary. The more people who you have been sexually active with, the more likely you are to get an HPV infection. This also applies to the number of sexual partners your partner may have had. When sexually active, using a condom correctly can greatly reduce the chances of being exposed to HPV as well as other sexually transmitted illnesses and viruses. But sex with just one person or even contact that you wouldn’t think of as sexual can be enough to spread HPV. According to the Centers for Disease Control, about 10% of all children have been exposed to HPV 16, the most cancerous of the HPV types, in their first ten years of life. This sounds scary but remember that 90% of cases of HPV clear up all by themselves-without any long-lasting effects-in two years or less.
Q: Should boys get Gardasil?
A: Merck is asking the FDA to approve Gardasil for boys and men, because it can prevent genital warts. It can also prevent anal and throat cancers, but those cancers are rare (although more common among gay men than heterosexual men).
However, until we know how long Gardasil can protect against the viruses causing cancer or genital warts, and until we know more about the risks of side effects, it is impossible to know if the benefits outweigh the risks for boys and men.