Researchers at Northwestern University no longer believe the only way HIV could enter the vaginal tract is if a woman has an open lesion on her skin, for example caused by the herpes virus.
Chicago (December 16, 2008) - Researchers at Northwestern University have discovered a critical new way a man can transmit the HIV virus to a woman.
Scientists thought the large HIV virus couldn't penetrate the tissue of the normal lining of the female vaginal tract. They long believed the healthy lining was an effective barrier to invasion of the HIV virus during sexual intercourse.
New research from Northwestern University's Feinberg School of Medicine has shown for the first time that the HIV virus does indeed penetrate a woman's normal, healthy genital tissue to a depth were it can gain access to its immune cell targets.
"This is an unexpected and important result," said Thomas Hope, principal investigator and professor of cell and molecular biology at the Feinberg School. "We have a new understanding of how HIV can invade the female vaginal tract.""Until now, science has really had no idea about the details of how sexual transmission of HIV actually works," Hope added. "The mechanism was all very murky." "We urgently need new prevention strategies or therapeutics to block the entry of HIV through a woman's genital skin," Hope said. While condoms are 100% effective in blocking the virus, "people don't always use them for cultural and other reasons," he noted.
Hope said researchers had also believed the only way HIV could enter the vaginal tract was if a woman had an open lesion on her skin, for example caused by the herpes virus. When breaks are present in the skin it should be easier for HIV to enter the skin and bind to and infect immune cells. But in studies where women were given anti-herpes drugs to decrease their lesions, there was no decrease in transmission. In light of the new results, it is possible that HIV can enter the vaginal tissue and initiate infection without any physical breaks.
"A big mistake in this field is the idea that transmission only takes place one way," Hope said. "Our perspective is the viruses can infect people in more than one way. We say one of those ways that needs to be in the equation is that the virus can be transmitted directly through the skin."
The next step will be to prove that the virus actually infects the immune cells in the vaginal tract. "A key experiment in the future is to identify the first cells to get infected in the epithelium, which is not necessarily where people would have looked for them before," Hope said.
Hope's research is funded by the NIH and the Center for HIV/AIDS Vaccine Immunology
Nationally Representative CDC Study Finds 1 in 4 Teenage Girls Have an STD
Chicago (March 11, 2008) – A CDC study released today estimates that one in four, 26% of young women between the ages of 14 and 19 in the United States are infected with at least one of the most common STDs. These include genital warts or human papillomavirus (HPV), chlamydia, herpes simplex virus, (HSV) and trichomoniasis. 2% were infected with herpes. Data came from the 2003-2004 National Health and Nutrition Examination Survey; 838 girls were in the study.
The study also found that African-American teenage girls were most severely affected. Nearly half of the young African-American women, 48% were infected with an STD, whereas 20% of young white and Mexican-American women were infected. “High STD infection rates among young women, particularly young African-American women, are clear signs that we must continue developing ways to reach those most at risk,” said John M. Douglas, Jr., M.D., director of CDC’s Division of STD Prevention. “STD screening and early treatment can prevent some of the most devastating effects of untreated STDs.”
In the study, only about half of the teenage girls admitted to having sex. Some teens defined sex as intercourse only, not including other types of intimate behavior such as oral sex, which can also spread diseases. An alarming 40% of those who admitted to having sex, had an STD!
U.S. health officials called for better screening, vaccination and prevention, since some STDs can cause infertility and cancer.
References:
Centers for Disease Control and Prevention
Vaccine Trial for Women to Help Protect Against Genital Herpes
GlaxoSmithKline Biologicals announced the launch of their phase III trial, called the “HERPEVAC Trial for Women”, due to begin in November 2002. They will be joined by the US National Institute of Health (NIH), a division of the Department of Health and Human Services, and the National Institute of Allergy and Infectious Diseases (NIAID). The NIH is recruiting 7,550 US female residents, ages 18 to 30, who are seronegative for both HSV-1 and HSV-2, for this phase of the trial. It seems that the vaccine is effective in women but not in men.
Results of the two previous phase III studies are published in the November 21 2002 issue of the New England Journal of Medicine. Professor Lawrence Stanberry, one of the chief investigators of the earlier phase III studies and Director of the Sealy Center for Vaccine Development at the University of Texas Medical Branch at Galveston, revealed: "The candidate herpes vaccine has demonstrated protection against genital herpes disease and a clear trend towards protection against infection has been observed in the subjects studied." Approximately 73% of women, who received the vaccine and were seronegative for HSV-1 and HSV-2 at the beginning of the trials, were protected against genital herpes.
References:
Stanberry L, et al. Glycoprotein-D-Adjuvant Vaccine to Prevent Genital Herpes. New England Journal of Medicine 2002; 347:1652-61
American Social Health Asssociaton (ASHA), “Genital herpes vaccine trial for women announced”
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