Still, doctors are eager to improve the existing line of treatment for the precancerous lesions called dysplasias.
"We usually operate on someone and there's a 50 percent chance that they'll have to come back to operate again," Ault said. "Therapeutic vaccines are something we're always interested in and there are a lot of things in the pipeline that are similar to this."
If therapeutic vaccine comes to market, doctors warn, it may never replace the need for surgical procedures on the cervix, as in the case of the study subjects, or the vulva.
"The most serious risk of vaccine treatment would be the delay in the diagnosis or treatment of an early, occult vulvar cancer," said Dr. Brent DuBeshter, director of gynecologic oncology at the University of Rochester Medical Center in New York.
Without a surgical excision, DuBeshter noted, it is not always possible to distinguish vulvar dysplasia from an early cancer.
"It should be noted that one of the study patients did develop an invasive cancer," said DuBeshter, who predicted the vaccine's "greatest role may be to help prevent recurrences, which are all too common."
Sue Turnbull, a clinical nurse who counsels nearly all the women who receive an abnormal pap smear at the West Virginia University Student Health Center in Morgantown, has seen the 10 percent of women infected with aggressive HPV strains come back repeatedly for tests and procedures.
She said the greater the number of operations on the cervix, the greater the likelihood that woman will have problems with a weakened, so-called compromised cervix later on. Women with the condition often require bed rest during pregnancy in order to prevent a premature birth.
"Really, there is no way right now to cure it once someone is exposed to HPV, but you can do things to hopefully keep it dormant by boosting your immune system," Turnbull said.
Women younger than 21 who are diagnosed with a low-grade abnormal pap smear are scheduled to be screened again in either six months or a year and told to boost their immune systems with more sleep, vitamins and a smoke-free environment, Turnbull said.
In 90 percent of these cases, she said, the immune system takes care of the lesions. "Unfortunately, I don't have a crystal ball to say you definitely will fall into this 90 percentile," Turnbull said.
Amanda, who wished to remain anonymous for privacy reasons, has experienced the trouble with screening and recurrences of the lesions. Now living in Houston, Amanda experienced a tortuous time on the East Coast after she went two years without a pap smear because of lack of health insurance.
"When I went the first time, they told me my pap came back abnormal," she said. "I went back a second time and it was normal. By 1999 [two years later], I finally had health insurance again so I went to get a pap and it was abnormal, cervical dysplasia level three, which is the one right before you have cancer."
Amanda went through two loop procedures to get rid of the lesions, the first of which was extremely painful.
"They were going to go in and scrape out the precancerous cells with some sort of wire thing," Amanda said. "She [the doctor] sprayed some sort of numbing stuff on me and it wasn't enough, so I started screaming."
After giving her a sedative and some more anesthetic, Amanda said the doctor continued the procedure. She rode home on a bus doubled over cramping, discharging blood. The pain lasted for weeks.
"I feel it was so invasive as a woman, they tell you it's going to be so easy, but it's still invasive," Amanda said. "I think a lot of women would prefer a less invasive treatment."