Two cervical cancer vaccines that are recommended for all pre-teen and early teen boys and girls miss the strains most likely to infect black women, researchers reported Monday.
But a new vaccine in advanced development may protect against many more of the strains, and in the meantime researchers say parents should definitely keep vaccinating their kids.
The findings, presented at a meeting of the American Association for Cancer Research, raise questions about whether minorities are adequately represented in research on new drugs and vaccines. More and more research shows that genetics plays a big role in how people respond to treatments, and this study shows that a virus passed from person to person in the most intimate of settings varies based on ethnic and social groups.
“It looks like we have different strains by race,” Cathrine Hoyo, an associate professor in Duke University’s obstetrics and gynecology department, told NBC News in a telephone interview.
“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,” Hoyo added.
Human papillomavirus may be the most common sexually transmitted infection. There are 40 different strains, and virtually everyone gets infected with one strain or another at least once in their lives. Usually, the body can clear it, but sometimes, the virus damages cells and causes cancer.
The Centers for Disease Control and Prevention estimates that 79 million Americans are infected with HPV right now, with 14 million more catching it each year.
It causes a range of cancers, including most cases of cervical cancer – which is diagnosed in more than 10,000 U.S. women every year. It can also cause head and neck cancer, including cancers of the throat and tongue, anal cancer and cancer of the penis. Actor Michael Douglas blamed HPV for his own case of head and neck cancer.
Hoyo’s team looked closely at 516 women being tested after having suspicious Pap smears. These tests look for changes in cells that could signal cancer. If something looks wrong, women get a follow-up examination called a colposcopy, where damaged-looking cells are removed and tested for both cancer and for HPV.
More than 70 percent of the women did have HPV infections. Most had more than one strain of the virus. White women had the most common strains, including HPV 16, 18, 31 and 45. African-Americans women were more likely to have HPV 33, 35, 58 and 68.
“African-American women were half as likely to carry HPV 18,” Hoyo said. That strain is included in both commercial HPV vaccines – Merck’s Gardasil and GlaxoSmithKline’s Cervarix. Gardasil protects against 6, 11, 16 and 18, while Cervarix protects against 16 and 18.
Hoyo says the findings do not mean that parents should delay vaccinating their kids. “I would do it now and do it again with the new vaccine,” Hoyo says.
Merck says Gardasil protects against 75 percent of cervical cancer cases. It’s in the final stages of developing a new HPV vaccine that protects against nine different strains of virus – it adds HPV 31, 33, 45, 52 and 58 to the mix.