Parties, drugs tied to spread of HIV
Sex parties and use of soft drugs could have contributed to the spread of HIV among three clusters of Hong Kong men who have genetically linked infections, the Centre for Health Protection said.
In its Communicable Diseases Watch e-newsletter released yesterday, the centre revealed findings of its investigations into three clusters of HIV cases involving 86 men who have sex with men (MSMs).
The first cluster, found in 2005, had grown to 66 men by the middle of this year. The second involved 12 men and the third had eight.
To establish 'unique risk factors', the centre interviewed 33 of the men who identified themselves as MSM and were also being treated at its Integrated Treatment Centre in Kowloon.
The centre also interviewed 57 HIV-positive MSMs who were being treated at the centre but were not linked to any cluster.
'Cluster cases were more likely than non-cluster cases to have participated in private group sex activities or so-called sex parties - 36 per cent versus 18 per cent,' the report said. The sex activities occurred mostly in homes or hotel rooms between an undefined number of people.
Taking soft drugs before or during sexual encounters was reported in 36 per cent of the cluster cases, versus 21 per cent of non-cluster cases, it added.
A spokesman for the centre said: 'Ecstasy and ketamine are the most commonly used drugs before or during sexual activities, and sex party participants are at risk of sexual contact with multiple anonymous partners.'
The centre found 73 per cent of cluster cases met casual sex partners through gay websites.
Seventy-three per cent of cluster cases reported more than 50 sex partners in their lifetime, compared with 53 per cent of non-cluster cases.
Past histories of sexually transmitted infections (STIs) were also reported in 76 per cent of the cluster cases compared to 44 per cent of those not in the clusters. Syphilis and anogenital warts were the most common infections among cluster cases.
'The relatively high CD4 counts in the cluster cases indicate that they were likely to be recent infections,' the report added. The number of CD4 or helper T-cells indicates the strength of an immune system - a way of measuring the progress of HIV infection.
The centre said it would release consolidated figures in March as investigators needed time to analyse data and establish connections to clusters. 'The driving forces behind the HIV growth in the MSM community are a high level of unprotected sexual risk behaviours, concurrent sexually transmitted diseases, use of internet to seek sex partners, participation in private group sex activities and the associated abuse of psychotropic substances.'
Three distinct clusters of male HIV cases have been identified
The percentage of HIV-positive men in the groups who are most likely to have been infected in Hong Kong 94%