Australasian Science: Australia's authority on science since 1938

Herpes Vaccine Trials Begin

By Stephen Luntz

Phase 1 trials are underway for a vaccine against the HSV-2 virus responsible for genital herpes.

An estimated 500 million people have HSV-2 infections. While many never experience an outbreak of the genital sores, they may still be infectious. For others “the virus causes pain and discomfort, and can have serious health implications for babies born to infected women,” says Prof Ian Frazer, who is leading research into the vaccine at the Diamantina Institute. Moreover, genital sores greatly increase the chance of HIV transmission.

Coridon, the company developing the vaccine, will inject 20 healthy individuals to test its safety and establish the dose required to generate a strong immune response. “Based on that we will know if we can move to the next stage or if we need to tweak the vaccine and test again,” says Coridon CEO Neil Finlayson.

The vaccine works by introducing a small section of DNA that uses the body’s cells to produce a protein that primes the immune system against HSV, both by causing the production of antibodies and by generating a cell-mediated response.

“Herpes infection can stay dormant in the spinal cord and sit in a latent stage in the ganglion, returning when the body is under stress,” Finlayson says. “Antibodies can protect against viral infection, but when someone is already infected you need a cell-mediated response where T-cells recognise the body’s own cells as infected and mount a response to clean up the virus.”

Finlayson says it is hoped the vaccine will prime the cell-mediated response to the point where, when an infection occurs, the body immediately fights it and sores do not form. However, he says that “the vaccine needs to be tested for both new infections and treatment”.

There are enough similarities in the surface proteins for HSV-1 and HSV-2 that Finlayson says there is a possibility the vaccine will also be useful against oral herpes or “cold sores”.

Even if trials succeed a commercial vaccine would be 6–10 years away, but Frazer and Finlayson have bigger plans. “The technology we have come up with could make vaccines for other viral diseases in virtually the same way,” says Finlayson. “We would have to look at each disease and select one or more proteins from a particular virus and apply the technology to develop a vaccine that primes both arms of the immune system. We think it could be applicable to any virus.”