A vaccine that appears to protect against four common strains of human papillomavirus virus – two that cause cervical cancer and two that cause genital warts – is under study at the Medical College of Georgia in women age 24-45.
"We have studied this vaccine in younger women and in children, who will be the primary target for vaccination in the future. However, there are millions of older women who may also want to be vaccinated against HPV," said Dr. Daron G. Ferris, family medicine physician, director of the MCG Gynecologic Cancer Prevention Center and a principal investigator on the vaccine study.
HPV, one of the most common sexually transmitted infections in the country, is the biggest risk factor for cervical cancer and a cause of penile cancer and genital warts. MCG has been involved in several national trials pursuing the efficacy of different HPV vaccines in different populations.
The quadrivalent vaccine currently under study protects against types 6 and 11, the top two wart-causing strains, and types 16 and 18, the two most-common cancer-causing strains. Dr. Ferris and his colleagues are concluding studies of the vaccine in women age 16-23 and in boys and girls age 10-15.
Many of the mothers with children in the previous study have expressed interest in participating in this latest study. "It's only natural now to look at the moms," Dr. Ferris said. "Although the greatest risk for HPV infection is in the 15- to 25-year-old age group, women between 30 and 40 are also at risk." Life changes, such as divorce, may kindle concerns about HPV infection, he said. A 1998 study of students at Rutgers University showed that 43 percent of study participants were infected with HPV over the 36 months they were followed; Dr. Ferris said the infection rate is closer to 25 percent for women age 24-45.
"It is important to remember that this vaccine is also a cancer-prevention vaccine: it will prevent 75 percent of cervical cancers," Dr. Ferris said. In fact, a study published in the November 2002 New England Journal of Medicine looking at the safety and efficacy of a vaccine that immunized against HPV type 16 alone showed that 100 percent of the women who received the vaccine were protected and no one developed precancerous changes related to type 16.
A study published this month in the Journal of Lower Genital Tract Disease by MCG researchers including Dr. Ferris showed that just a little education about the high incidence and risk of HPV infection, helped convince many parents to protect their children.
"We were concerned that parents may worry about vaccinating their children because it could be viewed as condoning sexual activity at an earlier age," Dr. Ferris said. "Our study showed that this is not the case." In fact, following a brief educational program, 37 percent of those who were initially concerned that study participation would condone earlier sex and 65 percent of those who simply weren't sure opted for the vaccine for their children.
When the study in children started, Dr. Ferris said he hoped that parents would see it as an opportunity to provide their children with protection against at least the most common strains of HPV and accompanying health hazards. "Our study shows the majority of parents do see this as important protection and the best time to get it is as a child," he said. In fact, should the Food and Drug Administration approve the vaccine for general use, the target audience likely will be children who are not yet sexually active, he said.
Participants in the new study will have nine office visits over three years that include physical and pelvic exams; Pap smears to detect cancerous or precancerous changes of the cervix; and HPV testing. Half the participants will receive vaccine in three doses; the rest will receive placebo. Office visits and tests will be provided at no cost and participants will be compensated for their time.
Women with a history of precancerous changes of the cervix are not eligible. Women who have had a biopsy of a cervical neoplasm but did not need further treatment can participate as long as five years have passed.
Source: Eurekalert & othersLast reviewed: By John M. Grohol, Psy.D. on 21 Feb 2009
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