Academic Journal
Main Category: Sexual Health / STDs
Also Included In: Immune System / Vaccines
Article Date: 09 Jan 2012 - 7:00 PST
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A study published in the New England Journal of Medicine reveals that an investigational vaccine protected some women against infection from one of the two types of herpes simplex viruses that cause genital herpes.
Leading author Robert Belshe, M.D., director of the Saint Louis University Center for Vaccine Development commented:
"There is some very good news in our findings. We were partially successful against half of the equation - protecting women from genital disease caused by HSV-1. It's a big step along the path to creating an effective vaccine that protects against genital disease caused by herpes infection. It points us in the direction to work toward making a vaccine that works on both herpes simplex viruses."
The study findings showed that the vaccine was partially effective at preventing herpes simplex virus type 1 (HSV-1), however it did not protect women from herpes simplex virus type 2 (HSV-2). Those women who received the investigational vaccine had fewer than half (58%) the cases of genital herpes caused by HSV-1 compared with women who received the control vaccine.
HSV-1 and HSV-2 are both members of the herpes virus family. Whilst HSV-2 generally causes lesions and blisters in the genital area, the HSV-1 virus typically causes mouth and lip sores, however it has also been increasingly found to cause genital disease. At present there is no cure or approved vaccine against genital herpes infections.
Approximately 25% of females in the U.S. are HSV infected, which makes it one of the most common communicable diseases. Once a person is infected, the HSV virus stays permanently in the person's body. It can cause severe neurological disease and even cause death in infants who are born to HSV infected women. The virus is also a risk factor for sexual transmission of HIV.
The clinical trial of the investigational genital herpes vaccine was conducted at 50 sites in the U.S. and Canada and involved 8,323 women aged between18 and 30 years who had no HSV-1 or HSV-2 infection at the start of the study. The researchers randomly assigned the women to receive either three doses of the investigational HSV vaccine that was developed by GSK or a hepatitis A vaccine as control.
The participants were followed for a duration of 20 months, during which the researchers thoroughly examined the women for occurrence of genital herpes disease. All participants undertook blood tests to establish whether asymptomatic infection with HSV-1 or HSV-2 occurred during the trial.
They discovered that two or three doses of the investigational vaccine provided substantial protection against genital herpes disease caused by HSV-1, however the vaccine did not protect women from genital disease caused by HSV-2.
Belshe, who also is a professor of infectious diseases and immunology at the Saint Louis University School of Medicine declared:
"We were surprised by these findings. We didn't expect the herpes vaccine to protect against one type of herpes simplex virus and not another. We also found it surprising that HSV-1 was a more common cause of genital disease than was HSV-2."
He added that HSV-1 infection has become an increasingly common cause of genital disease, which may be due to more couples engaging in oral sex. Both HSV-1 and HSV-2 are spread by direct contact, i.e. mouth to mouth, mouth to genitals and genitals to genitals, even when the infected person shows no symptoms.
The researchers are carrying out laboratory tests on serum obtained from study participants whilst they continue to examine the reason as to why the vaccine protected women from genital disease caused by HSV-1 but not HSV-2.
Belshe said that one hypothesis is that the HSV-1 virus is more easily killed by antibodies compared with the HSV-2 virus, meaning that the vaccine antibodies might work better against HSV-1 and therefore protects from HSV-1 but not HSV-2.
Previous studies of the investigational herpes vaccines showed that the vaccine protected women against genital herpes who were not infected with HSV-1 or HSV-2, but whose sexual partners were known to have genital herpes. The researchers hypothesize that the reason for the different outcome in the most recent clinical trial could be linked to the fact that different populations were studied as women in the previous studies may have been protected due to immunologic or behavioral factors that were not present in the later study.
Belshe commented:
"It's always important to confirm scientific findings in repeated studies, which is why we investigated the vaccine in a large, placebo controlled trial. Our findings confirmed the validity of the scientific process. You've got to have good scientific evidence that something actually works."
The study was funded by the National Institute of Allergy and Infectious Diseases (NIAID), which is part of the National Institutes of Health, together with GlaxoSmithKline (GSK).
Written by Petra Rattue
Copyright: Medical News Today
Not to be reproduced without permission of Medical News Today
MLA
26 Jan. 2012.
Please note: If no author information is provided, the source is cited instead.
posted by susangao on 9 Jan 2012 at 6:12 pm
"It's always important to confirm scientific findings in repeated studies, which is why we investigated the vaccine in a large, placebo controlled trial. Our findings confirmed the validity of the scientific process. You've got to have good scientific evidence that something actually works."
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