Safe vaccine to combat herpes infections

The unpleasant and painful sores, and infection of newborn babies caused by the genital herpes virus could soon be a thing of the past according to Dr Julian Hickling, who is presenting results from Xenova Research Ltd today, Tuesday 8 April 2003, to the Society for General Microbiology’s Spring Meeting in Edinburgh.

“The challenge is trying to achieve a good balance between safety and a vaccine that really works,” says Dr Hickling, Research Director, Biologics of pharmaceutical company Xenova. “Genital herpes viruses establish a life long infection in the patient, and may periodically re-activate to cause medical problems. From the public health perspective, genital herpes is a growing problem reaching epidemic proportions in some populations.”

The most effective vaccines are based on live but weakened forms of the virus. However the safest vaccines are based on killed organisms or small parts of the disease-causing organism. The Research and Development team at Xenova in Cambridge has engineered a new strain of the virus to take advantage of both these approaches.

The version created by the researchers is live, but can only survive for one single round of multiplication within the vaccinated person. Thus the vaccine should be as safe as a conventionally killed vaccine while being as immunogenic as a live virus. Data from phase I clinical trials of the engineered virus (termed DISC) support the theory.

“This approach should also be suitable for use against other members of the herpes virus family, such as cytomegalovirus which is a major cause of birth defects, and varicella which causes chickenpox and shingles,” says Dr Hickling.

“Apart from the urgent need to produce an effective vaccine for genital herpes, there is some evidence that infection with the herpes simplex virus increases the risk of acquiring or transmitting HIV,” says Dr Hickling. “It is therefore possible that an effective vaccine against this particular strain of herpes virus could help control the HIV epidemic.”