November 3, 2013 | by Denise Heady
HPV vaccines are a proven way to reduce the risk of contracting strains of human papillomavirus that can lead to cervical cancer, doctors have long said. Now a new study suggests the vaccines may be not be as effective for African-American women as they are for white women.
It appears that African-American women are more likely to have strains of human papillomavirus not included in the vaccines. The news may make some African-American women ask themselves: Why bother? But a City of Hope expert cautions against dismissing the vaccines just yet.
First some background on human papillomavirus:
HPV is the most common sexually transmitted infection, and includes more than 40 types that can infect the genital area. Some of these also cause genital warts. The federal Centers for Disease Control and Prevention estimates that 79 million Americans are currently infected with one of these strains and that 14 million more will become infected each year.
These types of HPV can cause a range of cancers, including vaginal, vulvar, penile and some oropharyngeal cancers, but cervical cancer is the most common. It's expected to be diagnosed in more than 12,000 women this year and take the lives of about 4,000 women, according to the American Cancer Society.
The two current HPV vaccines available, Gardasil and Cervarix, both protect against the two HPV subtypes, 16 and 18, that are believed to cause most cervical cancers. (Gardasil also protects against subtypes 6 and 11, which lead to genital warts.)
Now for the new results:
Researchers from Duke University School of Medicine found that African-American women were much less likely than white women to be infected with HPV types 16 and 18.
“We found a much lower prevalence of HPV 16 and 18 in advanced CIN (precancerous cervical abnormalities) from African-American women,” said study researcher Cathrine Hoyo, Ph.D., M.Ph.H., associate professor of obstetrics and gynecology at Duke University of Medicine in a news release. “Rather, their CIN2 and 3 frequently harbored HPV 31, 35, 45, 56, 58, 66 and 68, all which are linked to cervical cancer.”
The study, which was presented at the 12th Annual American Association for Cancer Research International Conference on Frontiers in Cancer Prevention Research, examined HPV strains in 572 women who had abnormal Pap tests. Of those women, 280 were African-American and 292 were white.
Early-stage abnormalities in white women were most likely to be linked to HPV 16, 18, 31, 56, 39 and 66. Early-stage abnormalities in African-American women were more likely to be linked to HPV 33, 35, 58 and 68.
Later-stage abnormalities in white women were most likely to be linked to 16, 18, 33, 39 and 59. For African-American women, they were most likely to be 31, 35, 45, 56, 58, 66 and 68.
“Although our findings need to be replicated in larger cohorts of women, they suggest that the current available HPV vaccines, which target HPV subtypes 16 and 18 in order to prevent cervical cancer and precancerous cervical abnormalities, will be less beneficial for African women than non-Hispanic white women,” Hoyo said in the news release.
But that doesn’t mean African-American women should forgo the current HPV vaccination, said Robert J. Morgan, M.D., co-director of City of Hope's Gynecological Oncology/Peritoneal Malignancy Program, in an interview with HealthDay.
"I don't think recommendations on vaccination would change [based] on this data," said Morgan, who was not involved in the research. Much more study is needed. And the risk is too great.
As Hoyo said in the release: "African-American women are about 20 percent more likely to develop cervical cancer and almost twice as likely to die from the disease compared with non-Hispanic white women." And they can be infected with strains 16 and 18, even if those may not be as common for them.
Currently, the HPV vaccination is recommended for preteen girls and boys at age 11 or 12 years old, before they become sexually active. It's also recommended for teenagers who didn't get the vaccine when they were younger, women through age 26 and men through age 21.