(RxWiki News) A vaccine to protect against herpes has shown some success for one strain of the virus, offering researchers hope that they're on the right path to a more comprehensive vaccine.
Although the test vaccine did not protect women from herpes simplex virus type 2 (HSV-2), it reduced the cases of HSV-1 by 58 percent in the women who participated in the trial.
"Practice safe sex to protect yourself against STDs."
Dr. Robert Belshe, MD, the director of the Saint Louis University Center for Vaccine Development and a professor at the Saint Louis University School of Medicine, led the trial of 8,323 women between the ages of 18 and 30. None had either herpes virus when the study began.
The women received either three doses of the trial vaccine, which was manufactured by GlaxoSmithKline, or three doses of the hepatitis A vaccine.
Researchers tracked the women at 50 different sites in the U.S. and Canada for 20 months and then gave them blood tests to determine if they had contracted either herpes virus. Those who had the trial vaccine contracted HSV-1 at a lower rate than the women who had the placebo vaccine.
"It's a big step along the path to creating an effective vaccine that protects against genital disease caused by herpes infection," said Belshe. "It points us in the direction to work toward making a vaccine that works on both herpes simplex viruses."
The researchers are doing further laboratory tests to determine why women were protected by one strain of the virus but not the other.
Two previous studies showed the vaccine to be 73 percent effective in protecting women against HSV-1 and 74 percent effective against HSV-2, but the populations used in those studies were different than the broader population in this study.
The HSV-2 form of herpes is the one that usually causes sores in the genital area while HSV-1 is usually responsible for mouth and lip blisters, though it can also cause genital disease.
"We didn't expect the herpes vaccine to protect against one type of herpes simplex virus and not another," Belshe said. "We also found it surprising that HSV-1 was a more common cause of genital disease than was HSV-2."
HSV-1 may have become a more common cause of genital disease because of an increase in couples who engage in oral sex, the researchers proposed.
Currently, no cure for herpes exists for the approximately 25 percent of U.S. women who have it.
No information regarding potential cost of the vaccine was provided in the study.
Among the adverse events or potential side effects reported, slightly more women receiving the herpes vaccine showed fatigue, fever, headache, and general ill feeling than the women who received the hepatitis vaccine.
The herpes shot also resulted in more redness, swelling and pain at the injection site than the hepatitis shot did, according to the study's results.
There were no other side effects that appeared at a statistically significantly greater rate in those who received the herpes vaccine instead of the placebo vaccine.
The study appears in the New England Journal of Medicine. It was funded by the National Institutes of Health (National Institute of Allergy and Infectious Diseases) and the pharmaceutical company GlaxoSmithKline (GSK).
Among the 14 authors of the study, seven, including Belshe, receive financial support, such as grants, consulting fees, travel fees and lecture fees, from GSK. Two of those seven are GSK employees.
Four of these seven authors, and three of the other authors, also receive financial support in some form or own stock options in other medical or pharmaceutical companies, including Roche, Pfizer, Genocea, Abbott Diagnostics, MedImmune, Merck, Novartis, and AiCuris.