- Category: Human Papillomavirus (HPV)
- Published on Monday, 12 November 2012 00:00
- Written by Liz Highleyman
HIV positive women may benefit from immunization against cancer-causing human papillomavirus (HPV) types, even though they are likely to have been exposed to some types of the virus previously, according to a study in the November 1, 2012, Journal of Acquired Immune Deficiency Syndromes. A majority of study participants remained susceptible to the most common high-risk types, HPV-16 and HPV-18.
HPV is the most common sexually transmitted infection worldwide. Oncogenic types of HPV, including HPV-16 and HIV-18, are the usual cause of cervical, anal, and genital cancers; several other types cause warts and other benign skin growths.
There are currently 2 approved and widely available HPV vaccines: Gardasil, a quadrivalent vaccine protecting against types 6, 11, 16, and 18; and Cervarix, a bivalent vaccine protecting against types 16 and 18.
Because people typically are exposed to HPV soon after they become sexually active, immunization is recommended for adolescents and young adult women and men from the ages of around 10 to 26 years. There is some controversy about whether HPV vaccines are still beneficial after people start having sex, as well as whether they may also work for older age groups.
Vaccination is an important issue for people with HIV, who tend to carry more different HPV strains, are less likely to clear the virus naturally, and may experience more rapid progression from mild abnormal cells to dysplasia or intraepithelial neoplasia, and eventually to cancer if left untreated. Despite effective antiretroviral therapy (ART) that preserves or restores CD4 T-cell counts, HIV positive people have elevated rates of anal and cervical neoplasia and cancer.
Jessica Kahn from the University of Cincinnati College of Medicine, Kathleen Squires from Thomas Jefferson University, and colleagues looked at the prevalence and risk factors for HPV infection among 99 HIV positive young women at 14 sites who were receiving their first dose of the 3-shot quadrivalent vaccine series.
Participants ranged in age from 16 to 23 years, with a mean of 21 years. About one-third were on ART. They were asked about behavioral and other risk factors and tested for HPV DNA from 41 different types (out of about 100 known HPV types) in cervico-vaginal samples.
- 74.7% of women tested positive for at least 1 HPV type.
- 53.5% had at least 1 high-risk or cancer-causing type, including 12.1% with HPV-16 and 5.1% with HPV-18.
- However, a slim majority tested negative for HPV-16 (55.6%), three-quarters (73.7%) did not have HPV-18, and 45.5% had neither of these high-risk types.
- In a multivariable analysis, the 3 factors independently associated with having high-risk HPV types were:
o Non-Hispanic black race/ethnicity: adjusted odds ratio (OR) 7.06, or about 7 times higher risk compared with white women.
o HIV viral load > 400 versus copies/mL: adjusted OR 3.47, or about 3.5-fold higher risk than those with lower HIV levels.
o Frequency of vaginal sex during the past 90 days: adjusted OR 5.82, or nearly 5-fold higher risk for those who had sex 6 or more times compared with those who reported not having sex at all.
"The prevalence of > 1 HPV type was high in these young women, demonstrating the importance of vaccinating before sexual initiation," the study authors concluded. "However, most women were HPV DNA negative and seronegative for high-risk vaccine-type HPV infection, supporting vaccination of sexually experienced HIV positive young women."
"‘Health care providers may hesitate to recommend HPV vaccines after a girl starts having sex," Kahn said in a press release issued by the National Institutes of Health, which funded the study. "However, our results show that for a significant number of young women, HPV vaccine can still offer benefits. This is especially important in light of their HIV status, which can make them even more vulnerable to HPV's effects."
"Even among women who test positive for one type of HPV, the vaccine may effectively prevent infection with others -- especially high-risk forms that cause cancer," she added. "It’s important that doctors don't withhold the vaccine in these cases, thinking that it's too late for a vaccine to be effective."
JA Kahn, RB Burk, KE Squires, et al. Prevalence and Risk Factors for HPV in HIV-Positive Young Women Receiving Their First HPV Vaccination. Journal of Acquired Immune Deficiency Syndromes 61(3):390-399. November 1, 2012.
National Institutes of Health. HPV vaccine may benefit HIV-infected women. Press release. November 8, 2012.