GENITAL herpes, which can be life-threatening if passed to newborns, may soon
be on the run thanks to a new vaccine against the herpes simplex virus. Clinical
tests just completed show there are just a couple of catches. The vaccine
doesn鈥檛 work for men, or for women who are infected with the related virus that
causes cold sores.
In the US, genital herpes is reaching epidemic proportions with up to a fifth
of the population estimated to be carrying the virus. Many infected people have
no symptoms. But the virus can lie low in the body, causing recurrent outbreaks
of genital blisters and fever. Genital herpes can also be passed from mother to
baby during birth. When this happens it can cause blindness and life-threatening
illness in the infant.
An international team organised by the drugs company SmithKline Beecham has
developed a vaccine that gives women good protection against the virus, the
ICAAC conference heard. 鈥淭his is a breakthrough development,鈥� says team member
Spotswood Spruance of the University of Utah in Salt Lake City. 鈥淲e have a grip
on the herpes virus for the first time.鈥�
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The researchers made the vaccine using part of the outer coat of the herpes
simplex 2 virus (HSV-2), which causes recurrent genital herpes. Herpes simplex 1
(HSV-1) is normally associated with cold sores. Both viruses can be shed without
causing symptoms, which makes it difficult for people to avoid spreading the
virus to their partners.
The team tested the vaccine on 3500 people in long-term relationships where
one partner was known to be infected with HSV-2. While 10 per cent of a control
group contracted the disease, only 2.5 per cent of vaccinated women showed signs
of infection. However, blood tests showed that some of the symptom-free women
had been infected with the virus. The researchers don鈥檛 yet know whether these
women are infectious.
The vaccine had little effect in men. The researchers suspect that antibodies
in vaginal secretions may be important.
Even among women, the vaccine only worked if they had never had either HSV-1
or HSV-2. Given that more than half of people in their thirties have been
exposed to HSV-1, any vaccination programme would need to be aimed at young
girls.
The development of the vaccine is particularly valuable in the light of
recent evidence that condoms don鈥檛 guarantee protection against herpes
infection. 鈥淔or a long time, we suspected that condoms don鈥檛 work,鈥� says Raj
Patel, an HSV expert at Southampton University.
