Vaccines recommended for preventing Human Papillomavirus (HPV), which causes cervical cancer, may be less effective in black women that whites, a new study suggests. The currently available vaccines, Gardasil and cervarix, don’t target the types of HPV infection found most often in black women, the study author said.
Experts have long believed that most cervical cancers are caused by persistent infection with subtypes of the sexually transmitted virus known as HPV 16 and HPV 18. These are the strains targeted by Gardasil and Cervarix. (Gardasil also targets HPV 6 and HPV 11).
But black women tend to develop cancer of the cervix, the lower part of the uterus or womb and die from it more often than white women, even when screening programs are similar, according to background information included in the study. This led the researchers to wonder if blacks might be less likely to benefit from vaccination.
Study researcher, Catherine Hoyo, associate professor of obstetrics and gynecology at the Duke University School of Medicine states that HPV 16 and 18 occur less frequently in African-Americans than in white. Her team looked at women who had abnormal results on Pap tests (screenings to detect precancerous cervical abnormalities. Of the nearly 600 women with Pap smear abnormalities in the study, about 86 percent had detectable HPV.
Hoyo said that African-Americans had half the HPV 16 and 18 frequency as whites did. She included that the findings, if replicated in larger studies, could call into question the effectiveness of the current vaccines for all races.
Dr. Robert Morgan, co-director of the gynecological oncology program at the City of Hope Comprehensive Cancer Centre in Daurte, Calif adviced that women should still get an HPV vaccines. He states; “ I don’t think recommendations on vaccination would change based on this data.
The America Cancer Society estimates that more than 12,000 new cases of cervical cancer will be diagnosed this year, and more than 4,000 women will die of the disease. Blacks are about 20 percent more likely to get cervical cancer, Hoyo said and about twice are likely to die from its as white women.
The U.S. Centre for Disease Control and Prevention recommends HPV vaccination for preteen boys and girls at age 11 or 12, before sexual activities begins. The vaccines, given in three injections over a six-month period, cost about $400 or more total.
In developing Gardasil and Cervarix, scientist relied on studies to pinpoint the strains of HPV most likely to lead to cancer. Studies were done on all ethnicities, Hoyo said, nothing that there may have been insufficient numbers of black women in the research studies to pick up differences in HPV subtypes.
Conclusively Hoyo said the findings however, are not a reason for blacks not to get an HPV vaccine. Testing of vaccines that target additional HPV subtypes are under way and in time the problem may be solved.