'Prevention Packages' Could Curb HIV Transmission Between Men

Combining available preventive interventions could avert at least one-quarter of new HIV infections among men who have sex with men, according to a statistical model based on transmission data from the United States, Peru, India, and Kenya.

Men who have sex with men continue to be at substantial risk for HIV infection worldwide. In many high-income countries, they are the only demographic group that continues to have a rising risk for acquiring HIV. In the United States, their risk for acquiring HIV infections is estimated to be increasing at approximately 8% per year for each year since 2001, Dr. Chris Beyrer of Johns Hopkins University, Baltimore, and his associates said in a paper published in a special edition of the Lancet.

Risk factors include unprotected receptive anal intercourse, high frequency of male partners, high number of lifetime male partners, injection drug use, high viral load in the infected partner, African-American ethnic origin (in the United States), and noninjection drug use. The disproportionate HIV disease burden in men who have sex with men is explained largely by the high per-act probability of HIV transmission in unprotected receptive anal sex, a rate estimated at 1.4% and approximately 18 times greater than the rate estimated for penile-vaginal intercourse, Dr. Beyrer and his associates reported.

In a separate paper published in the Lancet issue, Patrick S. Sullivan of Emory University, Atlanta, and his associates reviewed data from 60 articles that tested putative HIV prevention interventions in men who have sex with men (MSM). Overall, the data suggest that combinations of prevention approaches, or so-called "prevention packages," are far more likely to succeed than are individual interventions. And, such prevention packages are more likely to succeed "if they target several points in the pathway to HIV infection, address major drivers of HIV epidemics with effective primary interventions, improve the effectiveness of these interventions through combination, and provide basic strategies that support prevention and respect ethical imperatives for MSM."

The investigators modeled three prevention packages based on use of condoms, oral preexposure prophylaxis – the use of antiretroviral medication in uninfected partners of HIV-discordant couples – and increased/earlier antiretroviral initiation. According to the model, between 11% and 29% of incident HIV infections would be averted over 10 years if oral preexposure prophylaxis and antiretroviral treatment coverage were assumed to be 40% and if 20% of unprotected anal intercourse encounters were replaced with condom-protected intercourse.

Increasing preexposure prophylaxis coverage from 20% to 80% increased the estimated cumulative proportions of infections averted. Increasing the frequency of preexposure prophylaxis adherence in men from 50% to 75% resulted in higher estimates of averted HIV incidence in all countries compared with baseline. However, the number of infections averted did not rise when the proportion of men with sufficient adherence was increased from 75% to 90%.

Dr. Sullivan and his associates noted that condoms were a primary focus of prevention efforts at the beginning of the AIDS epidemic, and remain one of the most effective methods for prevention of HIV transmission in HIV-discordant couples. However, condom use in MSM is problematic. Issues include difficulty in negotiating condom use with sexual partners, condom slippage or breakage, and condom availability in developing countries, the authors noted.

Now, there is increasing focus on preexposure prophylaxis. On July 16, the Food and Drug Administration approved daily tenofovir and emtricitabine (Truvada) for postexposure prophylaxis among HIV-negative high-risk individuals, including MSM.

Data supporting the FDA licensure included those from a trial of 2,499 MSM and transgender women. Use of Truvada was associated with a 44% reduction in the frequency of HIV infections at a median follow-up of 1.2 years compared with placebo. Truvada was fairly well tolerated, but was associated with a transient but significant increase in nausea and unintentional weight loss in the tenofovir and emtricitabine group. Self-reported compliance was 89% or greater at week 4, but participants’ drug concentrations suggested that actual adherence was probably lower (N. Engl. J. Med. 2010;363:2587-99).

But health care roadblocks remain, Dr. Sullivan and his associates said. "In many cases, coverage will be poor irrespective of funding until men can safely access care, comfortably discuss their sexual risks for HIV with health-care providers, receive referrals for appropriate services, and confidently use prevention methods and services that will reduce their risks of acquisition or transmission of HIV infection."

"The next steps in HIV prevention in MSM will be technically difficult and costly. Proof-of-concept studies of combination prevention approaches should be followed by large, multicenter prevention trials of promising packages," they concluded.

All authors of both papers declared that they have no financial conflicts of interest.

Combining available preventive interventions could avert at least one-quarter of new HIV infections among men who have sex with men, according to a statistical model based on transmission data from the United States, Peru, India, and Kenya.

Men who have sex with men continue to be at substantial risk for HIV infection worldwide. In many high-income countries, they are the only demographic group that continues to have a rising risk for acquiring HIV. In the United States, their risk for acquiring HIV infections is estimated to be increasing at approximately 8% per year for each year since 2001, Dr. Chris Beyrer of Johns Hopkins University, Baltimore, and his associates said in a paper published in a special edition of the Lancet.

Risk factors include unprotected receptive anal intercourse, high frequency of male partners, high number of lifetime male partners, injection drug use, high viral load in the infected partner, African-American ethnic origin (in the United States), and noninjection drug use. The disproportionate HIV disease burden in men who have sex with men is explained largely by the high per-act probability of HIV transmission in unprotected receptive anal sex, a rate estimated at 1.4% and approximately 18 times greater than the rate estimated for penile-vaginal intercourse, Dr. Beyrer and his associates reported.

In a separate paper published in the Lancet issue, Patrick S. Sullivan of Emory University, Atlanta, and his associates reviewed data from 60 articles that tested putative HIV prevention interventions in men who have sex with men (MSM). Overall, the data suggest that combinations of prevention approaches, or so-called "prevention packages," are far more likely to succeed than are individual interventions. And, such prevention packages are more likely to succeed "if they target several points in the pathway to HIV infection, address major drivers of HIV epidemics with effective primary interventions, improve the effectiveness of these interventions through combination, and provide basic strategies that support prevention and respect ethical imperatives for MSM."

The investigators modeled three prevention packages based on use of condoms, oral preexposure prophylaxis – the use of antiretroviral medication in uninfected partners of HIV-discordant couples – and increased/earlier antiretroviral initiation. According to the model, between 11% and 29% of incident HIV infections would be averted over 10 years if oral preexposure prophylaxis and antiretroviral treatment coverage were assumed to be 40% and if 20% of unprotected anal intercourse encounters were replaced with condom-protected intercourse.

Increasing preexposure prophylaxis coverage from 20% to 80% increased the estimated cumulative proportions of infections averted. Increasing the frequency of preexposure prophylaxis adherence in men from 50% to 75% resulted in higher estimates of averted HIV incidence in all countries compared with baseline. However, the number of infections averted did not rise when the proportion of men with sufficient adherence was increased from 75% to 90%.

Dr. Sullivan and his associates noted that condoms were a primary focus of prevention efforts at the beginning of the AIDS epidemic, and remain one of the most effective methods for prevention of HIV transmission in HIV-discordant couples. However, condom use in MSM is problematic. Issues include difficulty in negotiating condom use with sexual partners, condom slippage or breakage, and condom availability in developing countries, the authors noted.

Now, there is increasing focus on preexposure prophylaxis. On July 16, the Food and Drug Administration approved daily tenofovir and emtricitabine (Truvada) for postexposure prophylaxis among HIV-negative high-risk individuals, including MSM.

Data supporting the FDA licensure included those from a trial of 2,499 MSM and transgender women. Use of Truvada was associated with a 44% reduction in the frequency of HIV infections at a median follow-up of 1.2 years compared with placebo. Truvada was fairly well tolerated, but was associated with a transient but significant increase in nausea and unintentional weight loss in the tenofovir and emtricitabine group. Self-reported compliance was 89% or greater at week 4, but participants’ drug concentrations suggested that actual adherence was probably lower (N. Engl. J. Med. 2010;363:2587-99).

But health care roadblocks remain, Dr. Sullivan and his associates said. "In many cases, coverage will be poor irrespective of funding until men can safely access care, comfortably discuss their sexual risks for HIV with health-care providers, receive referrals for appropriate services, and confidently use prevention methods and services that will reduce their risks of acquisition or transmission of HIV infection."

"The next steps in HIV prevention in MSM will be technically difficult and costly. Proof-of-concept studies of combination prevention approaches should be followed by large, multicenter prevention trials of promising packages," they concluded.

All authors of both papers declared that they have no financial conflicts of interest.

Combining available preventive interventions could avert at least one-quarter of new HIV infections among men who have sex with men, according to a statistical model based on transmission data from the United States, Peru, India, and Kenya.

Men who have sex with men continue to be at substantial risk for HIV infection worldwide. In many high-income countries, they are the only demographic group that continues to have a rising risk for acquiring HIV. In the United States, their risk for acquiring HIV infections is estimated to be increasing at approximately 8% per year for each year since 2001, Dr. Chris Beyrer of Johns Hopkins University, Baltimore, and his associates said in a paper published in a special edition of the Lancet.

Risk factors include unprotected receptive anal intercourse, high frequency of male partners, high number of lifetime male partners, injection drug use, high viral load in the infected partner, African-American ethnic origin (in the United States), and noninjection drug use. The disproportionate HIV disease burden in men who have sex with men is explained largely by the high per-act probability of HIV transmission in unprotected receptive anal sex, a rate estimated at 1.4% and approximately 18 times greater than the rate estimated for penile-vaginal intercourse, Dr. Beyrer and his associates reported.

In a separate paper published in the Lancet issue, Patrick S. Sullivan of Emory University, Atlanta, and his associates reviewed data from 60 articles that tested putative HIV prevention interventions in men who have sex with men (MSM). Overall, the data suggest that combinations of prevention approaches, or so-called "prevention packages," are far more likely to succeed than are individual interventions. And, such prevention packages are more likely to succeed "if they target several points in the pathway to HIV infection, address major drivers of HIV epidemics with effective primary interventions, improve the effectiveness of these interventions through combination, and provide basic strategies that support prevention and respect ethical imperatives for MSM."

The investigators modeled three prevention packages based on use of condoms, oral preexposure prophylaxis – the use of antiretroviral medication in uninfected partners of HIV-discordant couples – and increased/earlier antiretroviral initiation. According to the model, between 11% and 29% of incident HIV infections would be averted over 10 years if oral preexposure prophylaxis and antiretroviral treatment coverage were assumed to be 40% and if 20% of unprotected anal intercourse encounters were replaced with condom-protected intercourse.

Increasing preexposure prophylaxis coverage from 20% to 80% increased the estimated cumulative proportions of infections averted. Increasing the frequency of preexposure prophylaxis adherence in men from 50% to 75% resulted in higher estimates of averted HIV incidence in all countries compared with baseline. However, the number of infections averted did not rise when the proportion of men with sufficient adherence was increased from 75% to 90%.

Dr. Sullivan and his associates noted that condoms were a primary focus of prevention efforts at the beginning of the AIDS epidemic, and remain one of the most effective methods for prevention of HIV transmission in HIV-discordant couples. However, condom use in MSM is problematic. Issues include difficulty in negotiating condom use with sexual partners, condom slippage or breakage, and condom availability in developing countries, the authors noted.

Now, there is increasing focus on preexposure prophylaxis. On July 16, the Food and Drug Administration approved daily tenofovir and emtricitabine (Truvada) for postexposure prophylaxis among HIV-negative high-risk individuals, including MSM.

Data supporting the FDA licensure included those from a trial of 2,499 MSM and transgender women. Use of Truvada was associated with a 44% reduction in the frequency of HIV infections at a median follow-up of 1.2 years compared with placebo. Truvada was fairly well tolerated, but was associated with a transient but significant increase in nausea and unintentional weight loss in the tenofovir and emtricitabine group. Self-reported compliance was 89% or greater at week 4, but participants’ drug concentrations suggested that actual adherence was probably lower (N. Engl. J. Med. 2010;363:2587-99).

But health care roadblocks remain, Dr. Sullivan and his associates said. "In many cases, coverage will be poor irrespective of funding until men can safely access care, comfortably discuss their sexual risks for HIV with health-care providers, receive referrals for appropriate services, and confidently use prevention methods and services that will reduce their risks of acquisition or transmission of HIV infection."

"The next steps in HIV prevention in MSM will be technically difficult and costly. Proof-of-concept studies of combination prevention approaches should be followed by large, multicenter prevention trials of promising packages," they concluded.

All authors of both papers declared that they have no financial conflicts of interest.