Patient trials of genital herpes vaccine begin in London

LONDON — A new vaccine designed to prevent people with genital herpes from passing the virus on to their sexual partners has begun its first patient trials at a hospital in England.

Two healthy volunteers have been given the jab at the Chelsea and Westminster Hospital in London, in the first phase of a study that could eventually provide the first effective immunization against the incurable sexually transmitted infection.

The safety trial, which will eventually involve 42 people, comes after encouraging results in animal models, the Times Online reported March 4.

Scientists behind the study said that if the trials are successful, a vaccine could be ready for widespread use in about five years.

Vaccinations would initially be offered to the sexual partners of people who carry genital herpes to protect them from infection, though wider immunization is also a possibility. One in 10 adults carries herpes simplex virus 2 (HSV2), which causes genital herpes, though most do not know they are infected as they have few or no symptoms. It often lies dormant for long periods, causing intermittent episodes of painful sores.

It is highly contagious when sores are present, and while condoms and antiviral drugs reduce the risk they do not eliminate transmission. Drugs can control symptoms, but do not clear the virus from the body.

Earlier candidate vaccines failed to produce good protection because of HSV2’s ability to hide from the body’s immune system. BioVex, a biotechnology company, has designed the new ImmunoVex HSV2 vaccine to counter this problem. It is based on a live but weakened version of HSV2, which has been engineered to silence four genes that help the virus to hide from the immune system. This should allow it to generate an immune response capable of preventing infection.

Simon Barton, a consultant in genito-urinary medicine at Chelsea and Westminster Hospital who is running the study, said a genital herpes vaccine would have important benefits.

“For many of the people with genital herpes I look after, the big issue is having a way of protecting their partners,” he said. “They can reduce the risk of transmission by using condoms and taking antiviral drugs every day, but these are far from ideal and they do not reduce the risk to zero.”

Marian Nicholson, director of the United Kingdom’s Herpes Viruses Association, added that the trial is fully enrolled but to follow updates people can check the ‘What's New' page at, and for more general information on herpes simplex, check the other pages or call the help line at +44 845 123 2305."