News Round-up from the International Herpes Management Forum Conference, 27-29th February, Amsterdam

The 11th Annual Meeting of the International Herpes Management Forum (27-29 February 2004) lived up to its promise of providing a thought-provoking insight into some of the current issues surrounding the management of herpes infections. Here we bring you a 'hot off the presses' report highlighting some of the topics discussed.

Cold sore virus responsible for more than half of new cases of genital herpes in Japanese women

More than half of all cases of primary (first episode) genital herpes in Japanese women are caused by the HSV-1 virus, the virus more commonly associated with cold sores, according to researchers from the Teikyo University School of Medicine in Japan. In a recent study presented at the meeting, just under 700 Japanese women with genital herpes were tested to see which type of virus (HSV-1 or HSV-2) they had and were classified according to three categories: primary, recurrent and non-primary first episode. The results showed that about 60% of primary infections with genital herpes were caused by HSV-1, while recurrent and non-primary first episode cases were predominantly caused by HSV-2 (the virus usually associated with genital herpes). The study showed that the percentage of primary genital herpes caused by HSV-1 had in fact decreased slightly during the past three decades. In the period 1971-1979, 65.5% of cases of primary infections were caused by HSV-1, while the percentage had fallen to 54% in the period 1990-1999.

The Milan experience

Researchers in Milan, Italy, also examined the number of cases of genital herpes due to the HSV-1 virus. Historically, HSV-1 cases of genital herpes had been rare in Italy, despite the high rates of HSV-1 infection in the general population. However, a new study of 186 patients with genital herpes attending a sexually transmitted disease clinic in Milan showed that the occurrence of genital herpes caused by HSV-1 has been increasing rapidly, as observed in other countries. In this study, the number of HSV-1 patients increased from 0 in 2000 to 21 in 2002. The researchers also noted that the proportion of cases of genital herpes (HSV-1 and HSV-2 combined) represented by homosexuals had increased three-fold between 2000 and 2002.

The potential impact of suppressive therapy on the transmission of genital herpes

A team of researchers from London, UK, and North Carolina, USA, presented their predictions for the potential impact of suppressive antiviral therapy to reduce transmission of HSV-2 in the US population. The work was conducted in light of a recent multi-centre clinical trial which demonstrated that suppressive therapy with valaciclovir and safer sex counselling decreased transmission of HSV-2 infection by 48% (Newsdesk, October 2002). The researchers used a model to calculate a person's risk of HSV-2 infection based on their sex, age and level of sexual activity and estimated the potential impact if different percentages of the population used suppressive therapy. The results suggest that each percentage point increase of the HSV-2 positive population taking suppressive therapy corresponds with a reduction in the incidence by almost 1%. Thus use of suppressive therapy by 3% of HSV-2 positive individuals would lead to a reduction of 2.5% in the overall incidence of HSV-2, while use by 15% would result in a 14% reduction.

A new diagnostic test makes its debut

Delegates also heard that a new diagnostic test for HSV-2 appears to offer great potential.

The CAPTIATM HSV-2 IgG Type Specific ELISA was used among five population groups: expectant mothers, sexually active adults, a low prevalence population and patients who had tested positive for HSV-2 either via culture tests or according to the 'Western Blot' test. The results showed that the new test is highly sensitive and specific and is comparable to the HSV-2 Western blot test, which is currently regarded as the 'gold standard' technique for diagnosing herpes.

Reference: Abstracts presented at the 11th Annual Meeting of the IHMF, 27-29th February 2004, Amsterdam