US Health Department identifies further 18 effective HIV prevention programmes

The Centers for Disease Control and Prevention (CDC), the public-health branch of the US Department of Health and Human Services, have identified 18 more HIV prevention programmes whose efficacy stands up to scientific scrutiny well enough for them to be recommended. This brings the total number of officially ‘effective’ interventions to 57.

The CDC’s Prevention Research Synthesis (PRS) Project regularly monitors scientific literature for evidence of efficacious HIV prevention interventions and publishes the results online. It also works with the researchers and authors of these interventions through its Replicating Effective Programs (REP) project to develop user-friendly programme materials and publicise and disseminate them through its Diffusion of Effective Behavioral Interventions (DEBI) project.

Findings from the latest systematic review of HIV interventions, covering studies published between 2000 and 2004, were recently published in the American Journal of Public Health (Lyles).

Criteria for inclusion

The PRS identified 100 studies that satisfied the initial criteria, which were:

• Interventions had to be conducted in the USA.
• They had to be delivered to individuals or groups and outcomes had to measure changes in those individuals or groups versus a control group. For this reason, ten community-level interventions were not included in this review and will be covered in a forthcoming publication.
• They had to include at least one outcome measuring sexual or drug-injecting behaviour (such as condom use or instances of unprotected sex) and/or HIV testing behaviour and/or changes in the infection rates of HIV or sexually transmitted infections.

Out of these, they found 18 that satisfied the criteria for evidence of efficacy. These were:

• A statistically significant positive effect in at least one of the outcome measures (p = ≤ .05) and no significant negative effect in any outcome measure.
• At least three months’ follow-up; the study’s main outcome had to be measured at least three months after the cessation of the intervention.
• There had to be at least 70% retention of subjects in both control and intervention arms, and the study had to have at least 50 participants per arm.

Who took part – and who didn’t

A total of 12,456 people were included in the 18 studies, over a third of them (4295 people) in one large single study of ten individual counselling sessions in HIV-negative gay men, the EXPLORE study. Other study sizes ranged from 175 to 935 participants.

The majority of the new interventions (nine studies) targeted HIV-negative heterosexual adults. Five targeted drug users (injecting or otherwise), four targeted people with HIV, three targeted gay men, and three targeted high-risk young people. Thirteen had a majority of ethnic minority participants, and the lowest proportion of non-white participants in any study was 26%. Eight studies targeted women exclusively. (Categories are non-exclusive; for instance, one study targeted HIV-positive drug-using young people.)

The authors comment: “Although it is encouraging that many efficacious interventions…target important populations, many gaps still remain.” These include most gay men other than predominantly older white men: ethnic minority, young and drug-injecting gay men were largely absent. So were transgender people, HIV-positive drug injectors and rural populations (only one study, from Puerto Rico, took place in a non-urban setting).

How the interventions worked

The 18 studies were very varied in their design. Intervention time ranged from one hour to 32 hours. Ten were delivered to groups, five to individuals, and three to both. Facilitators ranged from experienced professionals to peers: five of the studies used trained peer facilitators, including three of the four interventions for people with HIV. Settings ranged from HIV, sexually transmitted infection (STI), psychiatric and family planning clinics (twelve studies) to community organisations or sites (seven studies). The EXPLORE study included phone counselling.

Most interventions taught skills building (condom use, communication and negotiation skills, relaxation and stress reduction) and the vast majority involved setting goals for risk reduction. The two interventions that targeted African-American teenagers included an abstinence component.

The most common significant positive outcome measured was a reduction in unprotected sex (twelve studies, including all three gay men’s studies). Eight studies reported increased condom use, three a reduced number of sexual partners and three reduced drug-injection risks. Four interventions produced a significant reduction in new STIs that was sustained for at least a year.

Of note, only the EXPLORE study was sufficiently powered to measure HIV incidence and it did not find a significant reduction in new infections.

Caveats and cautions

It is important to note that, in the words of the authors, “The interventions were identified as efficacious after being evaluated with a particular target population in a particular setting, and often within a single site.” They were also conducted to the rigorous standards of a scientific study. So the findings may not be generalisable to other settings and populations, and where facilitators are less well trained or prepared. Non-US organisations should be particularly cautious in assuming that programmes can be transferred to other cultures.

The CDC did not attempt to rank interventions, but notes that “whereas some interventions led to long-term reductions in several risk behaviours, others produced short-term reductions that were not maintained over time.” And they made no evaluation of the cost-effectiveness of programmes.

Nonetheless, the PRS Project is the only one worldwide which even attempts methodically to separate the wheat from the chaff when it comes to HIV risk reduction programmes and interested parties may find it helpful to search the PRS and DEBI websites for programmes that could be adapted for local use.