Most gay men willing to consider PrEP for possible HIV exposure

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Three-quarters of gay and other men who have sex with men would be willing to take pre-exposure prophylaxis to prevent HIV infection, American researchers report in the January 1st 2009 edition of the Journal of Acquired Immune Deficiency Syndromes. The investigators hope their research will help identify men willing to participate in pre-exposure prophylaxis studies or who would benefit from pre-exposure prophylaxis programmes.

Approximately 1 million people in the US have been diagnosed with HIV. The majority of these infections are amongst gay men and other men who have sex with men and there is an urgent need to develop new methods of HIV prevention for this population.

Research into the development of an HIV vaccine has been disappointing and development of a microbicide is developing at a slow pace.

Glossary

post-exposure prophylaxis (PEP)

A month-long course of antiretroviral medicines taken after exposure or possible exposure to HIV, to reduce the risk of acquiring HIV.

multivariate analysis

An extension of multivariable analysis that is used to model two or more outcomes at the same time.

sample

Studies aim to give information that will be applicable to a large group of people (e.g. adults with diagnosed HIV in the UK). Because it is impractical to conduct a study with such a large group, only a sub-group (a sample) takes part in a study. This isn’t a problem as long as the characteristics of the sample are similar to those of the wider group (e.g. in terms of age, gender, CD4 count and years since diagnosis).

receptive

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

microbicide

A product (such as a gel or cream) that is being tested in HIV prevention research. It could be applied topically to genital surfaces to prevent or reduce the transmission of HIV during sexual intercourse. Microbicides might also take other forms, including films, suppositories, and slow-releasing sponges or vaginal rings.

Animal and human studies, however, suggest that prophylaxis with antiretroviral drugs may prove an effective means of preventing infection with HIV. Post-exposure prophylaxis is widely used in occupational settings and is becoming increasingly available for sexual and other, non-occupational, potential exposures to HIV.

Research is also underway into the safety and efficacy of pre-exposure prophylaxis. This strategy involves HIV-negative individuals with a high risk of HIV infection taking daily antiretroviral therapy to prevent infection with the virus.

Investigators wished to determine knowledge and acceptability of pre-exposure prophylaxis in a population of gay and other men who have sex with men, all of whom had a high risk of HIV infection, reporting unprotected anal sex with a male partner in the previous year.

The study was conducted in 2007 and involved 227 men recruited from the Boston area. All the men had a face-to-face interview with a researcher where they were asked to provide demographic information and details of their sexual behaviour, and queried about their knowledge of - and willingness to use - post-exposure prophylaxis and pre-exposure prophylaxis.

Mean age was 41 years; 46% of the men were white and 44% were African Americans. Most of the men had received a high school education or less, and almost half reported a low annual income (below $12,000 per year).

Only 41% of the men identified as gay, with a further 40% identifying as bisexual, 2% as straight/heterosexual and 16% as “other” (e.g. queer, prefer not to say, do not know).

All the men reported anal sex with another man in the previous year. Furthermore, three quarters reported unprotected insertive or receptive anal sex with at least one monogamous male partner in the past twelve months.

Only one man reported previous use of pre-exposure prophylaxis. This man received his treatment from his HIV-infected brother. Five men (2%) reported knowing someone who had used pre-exposure prophylaxis. The investigators were concerned that, despite high levels of HIV risk, only 19% of men had ever heard of pre-exposure prophylaxis.

The men who had heard of pre-exposure prophylaxis appeared, however, to be the men who took the greatest HIV risks. Factors associated with having heard of pre-exposure prophylaxis included having used post-exposure prophylaxis (p = 0.004), having had unprotected anal sex with a non-monogamous partner in the previous year (p = 0.02), having used methamphetamine during sex (p = 0.02), and meeting sexual partners online (p = 0.004).

Higher educational and social status were also associated with knowledge of pre-exposure prophylaxis, awareness of the treatment being associated with a college degree or higher (p = 0.001), and an income over $60,000 per year (p = 0.009).

Overall, 74% of the men said that they would be willing to use pre-exposure prophylaxis in the future, having been educated about its potential to prevent HIV infection.

In their first set of analysis, the investigators found that the following factors were associated with a willingness to consider pre-exposure prophylaxis: an income between $25,000 and $30,000 per year; free access to pre-exposure prophylaxis; no perceived side-effects; fewer than ten anonymous male partners in the previous year; self-identifying as a “barebacker” (engaging in unprotected anal sex with other men); no reported sexually transmitted infections; use of cannabis during sex; and being less optimistic about HIV treatment.

However, in multivariate analysis that controlled for age and race, the following factors remained significantly associated with a willingness to consider pre-exposure prophylaxis:

  • Less education (p = 0.04).
  • Income between $25,000 and $30,000 per year (p = 0.04).
  • No perceived side-effects from pre-exposure prophylaxis (p = 0.001).
  • Free access to pre-exposure prophylaxis (p = 0.05).

The investigators then looked at hypothetical situations when the men would be willing to consider pre-exposure prophylaxis. They found that 86% would be more likely to take such treatment everyday if they thought it would prevent HIV infection, 85% said they would be willing to take both pre-exposure and post-exposure prophylaxis after a “hot” date, and 89% said they would be willing to take pre-exposure prophylaxis for all unprotected anal sex.

The ovewhelming majority (86%) said they would be willing to take pre-exposure prophylaxis even if it involved taking more than one pill daily.

“The use of antiretroviral therapy for HIV prevention was unfamiliar in this high-risk sample of men who have sex with men, yet the potential for rapid scale-up of pre-exposure prophylaxis seemed highly feasible,” comment the investigators.

They conclude that their study shows that “investigators, public health officials, and the media need to be very careful to plan programs of community education that accurately reflect the results of ongoing and future pre-exposure prophylaxis efficacy trials and to anticipate how several key variables, including efficacy, side-effect profiles, and cost are explained to at-risk populations to ensure appropriate pre-exposure prophylaxis use if studies show partial efficacy.”

References

Mimiaga, MJ et al. Pre-exposure antiretroviral prophylaxis attitudes in high-risk Boston-area men who report having sex with men: limited knowledge and experience but potential for increased utilization after education. J Acquir Immune Defic Syndr 50: 77-83, 2009.

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