2008年11月9日星期日

Gardasil: Working to Prove Its Effectiveness

The somewhat controversial HPV vaccine Gardasil has been receiving a lot of press recently, from an allegedly too-quick FDA approval to praise for the high volume of vaccines being distributed. Gardasil, approved in 2006 to prevent 70 percent of cervical cancers and 90 percent of genital warts caused by HPV, is fast becoming an automatic vaccine for young girls entering puberty. With new information coming out of the CDC in the last week, it just may prove be deserved of the good press.
The Centers for Disease Control and Prevention (CDC) published a record of the HPV-related cancer occurrences from a five-year span prior to the popular vaccine’s debut. The United States government collected the data from 1998 to 2003 from 38 states and the District of Columbia. This data provided an estimated number of 25,000 HPV-related cancers reported each year.
HPV is a hidden infection that can be transferred by sexual contact and skin on skin interaction. As the most common sexual transmitted infection (STI), it is the least commonly taught in schools because 90 percent of the cases are fought off by the body’s immune system before the person even knows they have HPV. There are over 100 types of HPV with over 30 of the strains being spread by sexual activity. Right now the HPV vaccine is approved only for girls aged 9 to 26 because the younger age means there is a lower risk of being infected with HPV through sexual contact.
Dr. Mona Saraiya, the lead researcher from the CDC, believes that the results are pertinent in helping to project numbers for the future, "These estimates of HPV-associated cancers were collected prior to the development of HPV vaccine. This gives us baseline data to measure the impact of HPV vaccine and cervical cancer screening programs in reducing the incidence of cervical cancer and other HPV-associated cancers and pre-cancers."
Cervical cancer had by far the largest number of occurances according to the findings at about 10,800 annually. Even though Gardasil was first marketed generally for cervical cancer, it was recently approved to prevent vulva and vaginal cancers but there are many other cancers that can evolve from contracting HPV. Most people with infected with HPV show no symptoms and don’t develop any health problems but there is still a risk for cancer if not detected early. The other relevant cancers are head and neck, penile, and anus affecting both men and women. According to the study, head and neck cancers related to HPV were found at a surprising 7,400 per year with an annual increase of 3 percent each year of the study.
The results were also helpful in determining demographics with black and Hispanic women being more at risk for cervical cancer than non-Hispanic and white women. Women with a history of cervical cancer also run a higher risk of developing other non-invasive cancers of the vulva, vagina, and rectum. Men were also shown in the study separated by race, type of cancer, and occurrence. Men are at risk for anal, head and neck, and penile cancers, as well as the common warts caused by HPV, but smaller numbers indicate that about one-fourth of cancers related to HPV occur in men. Even though there is no immediate vaccination arranged for males yet, the CDC suggests that men as well as women have a regular screenings to check for the infection.
The study will be published in the November 15 print edition of Cancer and has already been produced online by the journal. The CDC report marks the largest U.S. HPV-associated cancer data to date, having broken down each study into specific numbers for each type of cancer and which demographic group had a larger percentage for each of the main HPV-trigger cancers.
Prevention is still the best way to catch HPV before it turns into cancer and we will know soon if Gardasil is doing what it’s supposed to. Hopefully in the next few years numbers will be collected from the same 38 states and the District of Columbia providing patients are still getting regular pap smears and screenings and possibly the vaccine to protect against HPV in order to diminish the results greatly. There are better screening tests now available and other pharmaceutical vaccines on the market, but no matter what type of prevention you use, researchers and doctors are urging caution at all costs.

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