Gay men diagnosed during primary infection substantially reduce their risk behaviour

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Gay and bisexual men who are diagnosed with HIV in the first few weeks after infection make significant changes to their sexual behaviour, write British researchers in the August issue of HIV Medicine. While risky behaviour was common before diagnosis, three-quarters of men surveyed posed no risk of onward transmission during the three months after their test result. The authors argue that this demonstrates the value of early diagnosis.

Moreover, they argue that more intensive risk-reduction counselling should be targeted towards men in primary infection, especially the minority who are most likely to continue with risk behaviours. They suggest that even short-lived changes in behaviour will have a significant impact on onward transmission.

Primary HIV infection is the period just after infection, during which HIV viral load and infectivity are exceptionally high. In addition, people with undiagnosed primary infection often continue to practice high-risk behaviour and may also be co-infected with sexually transmitted infections. For these reasons, it has been estimated that up to half of all HIV infections can be attributed to people with primary infection.


primary infection

In HIV, usually defined as the first six months of infection.

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.


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


Cost-effectiveness analyses compare the financial cost of providing health interventions with their health benefit in order to assess whether interventions provide value for money. As well as the cost of providing medical care now, analyses may take into account savings on future health spending (because a person’s health has improved) and the economic contribution a healthy person could make to society.


In HIV, refers to the act of telling another person that you have HIV. Many people find this term stigmatising as it suggests information which is normally kept secret. The terms ‘telling’ or ‘sharing’ are more neutral.

The researchers recruited 98 gay and bisexual men with primary HIV infection in London. The men completed electronic questionnaires within a week of diagnosis, and three months later. All information about reductions in risk behaviour therefore concerns only the first three months after diagnosis.

In common with other studies, when men gave data at diagnosis, they reported high levels of recreational drug use, high numbers of sexual partners and low rates of condom use. However an unusually high number (38%) had been paid for sex at some time in their lives.

There were significant changes in men’s sexual behaviour reported twelve weeks after diagnosis, and three quarters of participants were judged by the researchers to have no behaviour which posed a risk of onward transmission.

In terms of numbers of sexual partners, 65 of 96 men reduced their number of partners, 26 stayed the same, and seven had more.

Fifty two men had a regular partner, and 46 of them (88%) disclosed their diagnosis to the partner. Of the remaining eight men who did not, only two had unprotected sex with an HIV-negative partner.

The proportion always using condoms during insertive anal intercourse increased from 31% to 61%, and the proportion always using them when receptive increased from 17% to 64%. Only five individuals reduced their use of condoms during insertive sex.

There was also a 44% reduction in the number of men diagnosed with a new sexually transmitted infection (which would corroborate men’s self-reporting of risk behaviour) and a 29% reduction in the number of men using recreational drugs.

Nonetheless, 24 men were judged to have behaviour which still posed a transmission risk. Eight had unprotected sex with a regular partner whose HIV status was negative or unknown, while 16 had unprotected sex with a casual partner. Nonetheless, the majority of these men had decreased their number of sexual partners.

There were some differences between the characteristics of those who posed a transmission risk at follow-up and those who did not. Subsequent risk-takers were more likely (at diagnosis) to have had more than six partners in the past three months, to have a sexually transmitted infection or to use the recreational drug ketamine. The authors suggest that these factors could help identify men who might benefit from more intensive counselling.

The authors stress that men were provided only with standard safer-sex and post-diagnosis counselling. They do acknowledge that the study cannot distinguish between behaviour change as a result of knowledge of infection, and behaviour change as a result of behavioural counselling.

Moreover, the study does not compare the behaviour of men diagnosed during primary infection with the behaviour of men diagnosed at other times. As a result, it is not clear that the changes in behaviour are greater than in other recently diagnosed men.

The authors conclude: “Limited prevention resources need to be focused where they will be most effective, and this study indicates that an important component of HIV prevention should be targeted efforts to achieve rapid diagnosis of primary HIV infection in high-risk groups, which can greatly reduce transmission through (even transient) behaviour change, with extra counselling being directed to those most likely to pose an ongoing transmission risk. Identification of primary HIV infection requires a high frequency of testing, which is both feasible and cost-effective for high-risk individuals.”


Fox J et al. Reductions in HIV transmission risk behaviour following diagnosis of primary HIV infection: a cohort of high-risk men who have sex with men. HIV Medicine 10:432-438, 2009.