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University of Iowa News

April 7, 2005

PHOTO: Kevin Ault, M.D., UI associate professor of obstetrics and gynecology, discusses an experimental HPV vaccine with study participant Elizabeth King, who is also a UI medical student.

UI Helps Show Human Papillomavirus Vaccine Reduces Infection

University of Iowa researchers contributed to a study that showed that a combination vaccine significantly reduces, in women, new cases of infection and disease associated with four types of human papillomavirus (HPV) -- HPV 6, 11, 16 and 18.

Nearly 20 million Americans are infected with HPV, which is linked to cervical cancer, abnormal pap tests and genital warts.

Women receiving the vaccine were 90 percent less likely to have persistent infections with the four HPV types and related diseases -- including cervical pre-cancers and genital warts -- than women who received a placebo, or inactive, vaccine, the international team reported in the April 7 online issue of Lancet Oncology.

In addition, the vaccine was 100 percent effective in preventing genital warts and cervical pre-cancers related to any of the four HPV types (6, 11, 16 and 18).

The study was led by Luisa Villa, Ph.D., head of the Department of Virology at Ludwig Institute for Cancer Research in São Paulo, Brazil. Kevin Ault, M.D., associate professor of obstetrics and gynecology in the UI Roy J. and Lucille A. Carver College of Medicine, was a study author and led the UI portion of the study.

The study vaccine, Gardasil, was designed to prevent infection from the four HPV types because of their significant role in causing disease. Collectively, HPV 16 and 18 are associated with 70 percent of all cervical cancer cases. HPV 6 and 11 are associated with 90 percent of all genital warts.

"While there are 100 types of HPV, the experimental vaccine targets the four most common types in order to reduce the chances that women will get cervical cancer, genital warts or abnormal Pap smears," said Ault, who also is an associate professor of epidemiology in the UI College of Public Health and a member of the Holden Comprehensive Cancer Center at the UI.

"Most people, including young women who are susceptible, don't understand that HPV causes most cases of cervical cancer," Ault added.

The study involved 552 women aged 16 to 23 from Brazil, Europe and the United States. At the UI, 98 women participated through the Vaccine Trials Office.

The participants were randomly split into two groups with half assigned to receive the placebo vaccine and half assigned to receive the functional vaccine. Each participant received three injections over a six-month period, then were followed for two-and-a-half years after vaccination. Follow-up included testing to see if the women had HPV or HPV-related disease.

The researchers found disease, persistent infection or HPV presence without persistence in 36 women in the placebo group. In the vaccinated group, there was only one case of persistent infection and three case of HPV infection that did not last.

The vaccine caused an immune response, which researchers were able to measure. Women receiving the actual vaccine had much higher antibodies than women who received the placebo and who also a previous history of natural HPV infection.

The study was funded by Merck Research Laboratories.

Ault and other members of the research team have received honoraria for consulting.

Phase III clinical trials are underway to evaluate Gardasil in 25,000 participants worldwide.

For information on past HPV studies involving the UI, see

STORY SOURCE: University of Iowa Health Science Relations, 5137 Westlawn, Iowa City, Iowa 5224-1178

MEDIA CONTACT: Becky Soglin, 319 335-6660