Prevalence of genital HPV - HPV Vaccine

United States

See also: HPV: Prevalence of Genital HPV

According to the Centers for Disease Control and Prevention, by the age of 50 more than 80% of American women will have contracted at least one strain of genital HPV. Both men and women can be carriers of HPV. HPV is the most common sexually transmitted infection in the US. A large percentage of the American population is infected with genital HPV because HPV is highly communicable. As a result, American public health experts recommend widespread HPV vaccination.

Only a small percentage of women with HPV develop cervical cancer. Each year, between 250,000 and 1 million American women are diagnosed with cervical dysplasia, which is caused by HPV and is a potential precursor to cervical cancer. About 11,000 American women are diagnosed with cervical cancer every year, and about 3,700 die per year of the disease. Most cancers occur in those who have not had Pap smears within the previous five years.


HPV-induced cancers

There are 19 "high-risk" HPV types that can lead to the development of cervical cancer or other genital/anal cancers; some forms of HPV, particularly type 16, have been found to be associated with a form of throat cancer.[28] Studies have found that human papillomavirus (HPV) infection is responsible for virtually all cases of cervical cancer.

Condoms protect against HPV, but do not completely prevent transmission. College freshmen women who used condoms consistently had a 37.8% per patient-year incidence of genital HPV, compared to an incidence of 89.3% among those who did not.

No data is kept by the U.S. government on genital wart infection rates,[33] however it is estimated that 20 million people are presently infected with genital warts, and there are six million new cases of genital warts every year in the United States.


Worldwide

Worldwide, cervical cancer is the fifth most deadly cancer in women. There are an estimated 470,000 new cases of cervical cancer, and 233,000 deaths per year.


Vaccination and public health

Gardasil is available poster for a university health clinicAccording to the American National Cancer Institute, "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."

Current preventive vaccines protect against the two HPV types that cause about 70% of cervical cancers worldwide. Because of the distribution of HPV types associated with cervical cancer, the vaccines are likely to be most effective in Asia, Europe, and North America. Vaccines that protect against more of the types common in cancers would prevent more cancers, and be less subject to regional variation.

Only 41% of women with cervical cancer in the developing world are able to access medical treatment for their illness. Therefore, prevention of HPV by vaccination may be a more effective way of lowering the disease burden in developing countries than cervical screening.[citation needed] However, individuals in many resource-limited nations, Kenya for example, are unable to afford the vaccine.


Vaccine target populations

Gardasil and Cervarix are preventative vaccines and do not have efficacy for treating active HPV infection. They are recommended for women who are 9 to 25 years old who have yet to contract HPV. However, since it is unlikely that a woman will have already contracted all four viruses, and because HPV is primarily sexually transmitted, the U.S. Centers for Disease Control and Prevention has recommended vaccination for women up to 26 years of age.

When Gardasil was first introduced, it was recommended as a prevention for cervical cancer for women that were 25 years old or younger. New evidence suggests that all Human Papillomavirus (HPV) vaccines are effective in preventing cervical cancer for women up to 45 years of age.

In November 2007, Merck presented new data on Gardasil. In an investigational study, their HPV vaccine reduced incidence of HPV and 18-related persistent infection and disease in women through age 45. The study evaluated women who had not contracted at least one of the HPV types targeted by the vaccine by the end of the three-dose vaccination series. Merck planned to submit this data before the end of 2007 to the U.S. Food and Drug Administration (FDA), and to seek an indication for Gardasil for women through age 45.


Vaccination during pregnancy

In the Gardasil clinical trials, 1,115 pregnant women received the HPV vaccine. Overall, the proportions of pregnancies with an adverse outcome were comparable in subjects who received Gardasil and subjects who received placebo. However, the clinical trials had a relatively small sample size. Currently the vaccine is not recommended for pregnant women.The long-term effects of the vaccine on fertility are not known, but no effects are anticipated.


Vaccination of males

Gardasil can also be used in males to reduce their risk of genital warts and precancerous lesions caused by HPV. The reduction in precancerous lesions is expected to reduce the rates of penile and anal cancers in men. 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. From a public health point of view, vaccinating men as well as women might be useful if it decreased the virus pool within the population. Gardasil is in particular demand among gay men, who are at significantly increased risk for genital warts, penile cancer, and anal cancer.

As with females, the vaccine must be administered before infection with the HPV types covered by the vaccine occurs. Vaccination before adolescence makes it more likely that the recipient has not been exposed to HPV.

In the UK, HPV vaccines are licensed for boys aged 9–15. Merck, the maker of Gardasil, is expected to ask the U.S. Food and Drug Administration (FDA) for permission to market the vaccine in the United States for boys and men ages 9–26. The vaccine is already available in the United States and can be used off label for the vaccination of males.


Mechanism of action

The latest generation of preventive HPV vaccines is based on hollow virus-like particles (VLPs) assembled from recombinant HPV coat proteins. The vaccines target the two most common high-risk HPVs, types 16 and 18. Together, these two HPV types currently cause about 70 percent of all cervical cancer. Gardasil also targets HPV types 6 and 11, which together currently cause about 90 percent of all cases of genital warts.

Gardasil and Cervarix are designed to elicit virus-neutralizing antibody responses that prevent initial infection with the HPV types represented in the vaccine. The vaccines have been shown to offer 100 percent protection against the development of cervical pre-cancers and genital warts caused by the HPV types in the vaccine, with few or no side effects. The protective effects of the vaccine are expected to last a minimum of 4.5 years after the initial vaccination.

While the study period was not long enough for cervical cancer to develop, the prevention of these cervical precancerous lesions (or dysplasias) is believed highly likely to result in the prevention of those cancers.

Although a 2006 study suggests that the vaccines may offer limited protection against a few HPV types that are closely related to HPVs there are other high-risk HPV types are not affected by the vaccines. Ongoing research is focused on the development of HPV vaccines that will offer protection against a broader range of HPV types.[47] There is also substantial research interest in the development of therapeutic vaccines, which seek to elicit immune responses against established HPV infections and HPV-induced cancers.


Vaccine implementation

Main article: vaccination policy

In developed countries, the widespread use of cervical "Pap smear" screening programs has reduced the incidence of invasive cervical cancer by 50% or more. Current preventive vaccines reduce, but do not eliminate the chance of getting cervical cancer. Therefore, experts recommend that women combine the benefits of both programs by seeking regular Pap smear screening, even after vaccination.

HPV vaccine

Human papillomavirus (HPV) vaccine is a vaccine that prevents infection with certain species of human papillomavirus associated with the development of cervical cancer, genital warts, and some less common cancers (e.g., anal, vulvar, vaginal,penile.

Two HPV vaccines are currently on the market: Gardasil and Cervarix. Both vaccines protect against two of the HPV types that can contribute to the development of cervical cancer, and some other genital cancers; Gardasil also protects against two of the HPV types that cause genital warts.

Public health officials in Australia, Canada, Europe and United States recommend vaccination of young women against HPV to prevent cervical cancer and genital warts, and to reduce the number of painful and costly treatments for cervical dysplasia, which is caused by HPV. Worldwide, HPV is the most common sexually transmitted infection in adults. For example, more than 80% of American women will have contracted at least one strain of HPV by age fifty.

Although most women infected with genital HPV will not have complications from the virus, worldwide there are an estimated 470,000 new cases of cervical cancer that result in 233,000 deaths per year. About eighty percent of deaths from cervical cancer occur in poor countries. In the United States, most of the approximately 11,000 cervical cancers found annually occur in women who have never had a Pap smear, or not had one in the previous five years.

Since the vaccine only covers some high-risk types of HPV, experts still recommend regular Pap smear screening even after vaccination.

Gardasil has been shown to also be effective in males, though it has not yet been approved by the FDA to be marketed as such.

Safety

Gardasil is a 3 dose (injection) vaccine. There have been 24 million doses distributed in the United States, and there have been 13,758 Vaccine Adverse Event Reporting System (VAERS) reports following the vaccination. Ninety-three percent were reports of events considered to be non-serious (e.g., fainting, pain and swelling at the injection site (arm), headache, nausea and fever), and 7% were considered to be serious (death, permanent disability, life-threatening illness and hospitalization). There is no proven causal link between the vaccine and serious adverse effects - all reports are related by time only. That is, they are only related because the effect happened some time after the vaccination.

There have been 39 deaths among women who took the vaccine reported to the CDC. Six are currently under investigation, and seven are unconfirmed because of a lack of patient identification information. None of the other 26 confirmed deaths were linked to the vaccine. Guillain-Barré Syndrome (GBS), a rare disorder that causes muscle weakness, has been reported after vaccination with Gardasil. There is no evidence suggesting that Gardasil causes or raises the risk of GBS. Additionally, there have been rare reports of blood clots forming in the heart, lungs and legs. Most of those who suffered blood clots were already at risk from other factors, such as taking oral contraceptives.

Based on all of the information they have today, CDC continues to recommend Gardasil vaccination for the prevention of 4 types of HPV. Merck, the manufacturer of Gardasil, will continue to test women who have received the vaccine to determine the vaccine's efficacy over a lifetime

How Often Should You Have a Pap Smear?

The frequency in which women get Pap smears is not the same for everyone. While one woman may need an annual Pap smear, another woman may only need a Pap smear every three years. How often a woman needs a Pap smear depends on several factors, like age, general health, and findings from previous Pap smears.
When to Have Your First Pap SmearThe American Cancer Society recommends that women have their first Pap smear about three years after they become sexually active or by age 21, whichever comes first. Subsequent Pap smears should occur every two
years thereafter with a liquid based Pap test or annually with a conventional test.
The American College of Obstetricians and Gynecologists recommend women have an annual Pap until age 30.

If you are well over twenty one and you have never had a Pap smear, it is not too late to have start having regular screenings. Having a regular Pap smear may considerably reduce your risk of developing cervical cancer.Thirty and Over
Unless recommended by a physician, continue screenings annually or every two to three years. Women who have had previous abnormal Pap smears, infected with HPV, or at high risk for cervical cancer may need to be screened more frequently.

At age 30, women have the option of having an HPV test along with their Pap smear. The HPV test identifies women who are infected with high risk strains of HPV that could lead to cervical cancer, if left unmonitored or untreated.Age Sixty-Five and Over At age 65 to 70, women who have had no abnormal Pap smears within the
last 10 years may discontinue having regular Pap smears. This is a decision that has to be made with a physician or other clinician. For women who have a previous history of cervical cancer, abnormal Pap smears, or are at high risk for developing cervical cancer, should continue having regular screenings.


Why Your Daughter Should be Vaccinated with the HPV Vaccine

It is a common misunderstanding that the HPV vaccine is just a vaccine to prevent a sexually transmitted disease. While the human papillomavirus (HPV) is a virus transmitted through sexual contact like other STDs, it can lead to cervical cancer, vaginal cancer, anal cancer, vulvar cancer, and genital warts. HPV's role in the development of many other types of cancer is being investigated by researchers.

In June 2006, the FDA approved the use of Gardasil, an HPV vaccine, in young women ages 9 to 26. It is currently available at many doctor's and public health clinic's offices across the United States. The vaccine has spawned much controversy, which has led to many parents being confused and unsure about whether to have their daughter vaccinated.

Parents are encouraged to make an informed decision about vaccinating their daughters with the HPV vaccine. Talking to the family pediatrician and learning more about HPV and cervical cancer are both recommended by experts to help parents make a decision.

Why Should Your Daughter Get the HPV Vaccine?

1. Gardasil greatly reduces the chances that your daughter will develop cervical cancer. Gardasil protects against two types of HPV that cause 70% of all cases of cervical cancer, thus greatly reducing the risk of developing cervical cancer later in life. About 11,070 women in the United States are diagnosed with cervical cancer each year, and an estimated 3,780 die from the disease.

Because Gardasil does not protect against all types of HPV, women who are vaccinated still need to have regular Pap smears to detect any precancerous changes. The vaccine does not replace the Pap smear and regular Pap smears are necessary for optimum cervical health.

2. Gardasil protects young girls from the two common types of HPV that can cause genital warts. Vaccinated girls are protected from the two types of HPV that are responsible for 90% of genital warts. Genital warts can appear as cauliflower-like growths that can occur on, within, and around the vagina. They also can appear as flat growths that aren't prominent and can go unnoticed. Although genital warts do not pose any immediate health risk, they can be embarrassing for many women and can cause feelings of shame.

3. Gardasil greatly reduces the risk of developing other potentially life-threatening types of cancer. Vaccinating your daughter will greatly reduce the risk of her developing precancerous and abnormal vaginal and vulvar lesions that could become cancerous. The same types of HPV that cause cervical cancer are also linked to vaginal and vulvar cancer. Although less common than cervical cancer, vaginal and vulvar cancer are serious types of cancer that can be life-threatening.


How to Prevent and Reduce Your Risk of HPV

More studies are being done to determine HPV's role in the development of other types of cancer.

HPV is spread through skin-to-skin sexual contact -- no penile penetration or exchange of bodily fluids are needed to contract the virus. The virus is extremely common and it is estimated that more than 70% of the general population is infected with HPV. In most cases, HPV does not cause serious health consequences, like cancer. But for some people, HPV can lead to cancer.
How to Prevent HPV
Currently, there are only two HPV prevention methods: abstinence and the HPV vaccine. There are other ways to help reduce your risk of developing HPV, and those methods are discussed below.

Abstinence. Not having any sexual contact is an absolute way to prevent HPV. For most adults, complete abstinence is unrealistic, so other means of prevention and risk reduction should be followed.
HPV Vaccine. Aside from abstinence, the HPV vaccine is another effective means of preventing HPV. Although it doesn't protect against all strains of HPV, it does provide protection against the four strains of HPV that are most commonly associated with cervical cancer and genital warts.

The FDA approved the use of Gardasil, the HPV vaccine, in 2006. The target age for the vaccine is age 11 through 26, but can be given as early as 9 years of age. The goal is to vaccinate girls before they become sexually active and become exposed to HPV. It protects against two strains that are known to cause cervical cancer in women and two strains that are responsible for genital warts.


How to Reduce Your Risk Of HPV

Practice Safe Sex with a Condom. It is still unclear how good condoms are at decreasing the transmission of HPV, but studies show that women whose partner wore a condom every time they engaged in sexual intercourse cut their risk of developing HPV by about 70%. However, it's important to keep in mind that HPV is not transmitted via the exchange of bodily fluids. It is transmitted though sexual skin-to-skin contact. For example, during intercourse the penis is covered by the condom, leaving other areas of the genitals exposed. These exposed areas may come in contact with the vagina, thus possibly transmitting the virus. And, of course, it's not just heterosexual contact that can transmit the virus -- it's any type of sexual contact.
Limit the Number of Sexual Partners You Have. Limiting the number of sexual partners you have during your lifetime may decrease your risk of contracting HPV. Being in a monogamous, long-term relationship with someone also will greatly reduce your risk of contracting different strains of the virus. In fact, in a monogamous relationship where one or both partners are infected with HPV, the couple helps lower the possibility of becoming infected with another strain of the virus.
Article source : http://cervicalcancer.about.com/