Many HIV-positive gay men involved in HIV transmission risk without recognising it

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A substantial minority of HIV-positive gay who initially reported consistent condom use for insertive anal sex admitted on closer questioning to briefly inserting their unprotected penis into the anus of another man before putting on a condom in a US study published in the January 23rd edition of AIDS. The investigators describe this practice as “dipping” and although they admit that they do not know its risk of HIV transmission relative to unprotected insertive anal sex, they suggest that it is an important HIV risk behaviour missed by standard prevention methods.

The study recruited a total of 1,164 HIV-positive gay men in New York and San Francisco and ran from March 2000 to June 2001. The investigators noted that earlier research involving HIV-positive heterosexual men who reported “consistent” condom use found that a substantial number of men briefly inserted their penis into their partner’s vagina as part of sexual fore-play before putting on a condom for intercourse. The investigators wished to see if this was also true for HIV-positive gay men and anal sex.

Individuals were asked to provide detailed information about their sexual behaviour, including the number of partners in the past 90 days, if they had had insertive or receptive anal sex without a condom, and if so, whether ejaculation had taken place, the details of their partners’ HIV status, their race, current health and if they thought that condoms interfered with their sexual enjoyment. The study participants were also asked if they had “dipped” their penis into any of their partners. Dipping was defined as “teasing or playing with your partner by putting your penis in his ass just once or twice without a condom.”

Glossary

insertive

Insertive anal intercourse refers to the act of penetration during anal intercourse. The insertive partner is the ‘top’. 

p-value

The result of a statistical test which tells us whether the results of a study are likely to be due to chance and would not be confirmed if the study was repeated. All p-values are between 0 and 1; the most reliable studies have p-values very close to 0. A p-value of 0.001 means that there is a 1 in 1000 probability that the results are due to chance and do not reflect a real difference. A p-value of 0.05 means there is a 1 in 20 probability that the results are due to chance. When a p-value is 0.05 or below, the result is considered to be ‘statistically significant’. Confidence intervals give similar information to p-values but are easier to interpret. 

epidemiology

The study of the causes of a disease, its distribution within a population, and measures for control and prevention. Epidemiology focuses on groups rather than individuals.

receptive

Receptive anal intercourse refers to the act of being penetrated during anal intercourse. The receptive partner is the ‘bottom’.

risky behaviour

In HIV, refers to any behaviour or action that increases an individual’s probability of acquiring or transmitting HIV, such as having unprotected sex, having multiple partners or sharing drug injection equipment.

All the individuals who reported a partner who was HIV-negative or of unknown HIV status were included in the investigators' analysis (n=858). The investigators found that 154 of these individuals (18%) reported “dipping” with an HIV-negative or unknown HIV status man. In addition they found that 11% (69) of the 628 men who denied any unprotected insertive anal sex said that they had “dipped” and that 37% of men who reported unprotected insertive anal sex also reported “dipping.” The mean number of times each man “dipped” in the previous 90 days was 5.1

The investigators found that “dipping” was significantly associated with unprotected insertive anal sex (p<0.000), men of Latino origin (p=0.009) and a belief that condoms interfered with sexual enjoyment (p=0.013).

As current HIV risk-assessments do not take into account “dipping”, the investigators believe that “current estimates of sexual risk among [gay] men may be lower than what is actually occurring. In the present study, 11% of [gay] men reported that they did not engage in [unprotected insertive anal intercourse] when in fact they did, via “dipping". In particular, 773 acts of “dipping” occurred among HIV-positive men with HIV-negative partners that would not have been reported.”

The investigators admit that they do not know the HIV transmission risk of “dipping” relative to unprotected anal sex, but point out that an earlier Canadian study involving gay men found that delayed condom use was the third strongest predictor of HIV infection after no condom use at all or condom failure. The investigators conclude that further epidemiological research is required, so that accurate HIV prevention information can be provided about this potentially risky sexual activity.

Further information on this website

Sexual health factsheets

Hoff CC et al. Sexual risk of HIV transmission missed by traditional methods of data collection. AIDS 18: 340 – 341, 2004.