CDC updates list of effective HIV prevention programmes

Gus Cairns
Published: 07 December 2006

The Centers for Disease Control and Prevention in the USA has started to identify new effective HIV prevention programmes with a view to packaging and disseminating evidence-based interventions for national use.

The CDC’s HIV/AIDS Prevention Research Synthesis (PRS) Project already has a compendium of prevention interventions for which there is strong evidence of effectiveness (see reference), but it was last updated in 2000 and 18 out of 28 intervention studies in the compendium were published before 1996. This PRS Project compendium did not distinguish programmes aimed at people with HIV, which has since becoming a key strategy of the CDC’s Advancing HIV Prevention Initiative.

An article in the American Journal of Public Health (see Lyles) gives news about the latest update, which aims to compile a list of interventions firmly tailored for the post-HAART era.

The PRS project periodically scans journals for programmes that provide convincingly effective HIV prevention outcomes. They use strict criteria for study design, quality of implementation and analysis and strength of evidence, and the present review produced an initial 21,039 journal citations. These were narrowed down to 176 studies that provided relevant outcome data, of which only 18 satisfied the other requirements.

Exclusion criteria

There were important exclusion criteria, too. Retrospective studies that analysed an intervention with hindsight were excluded. Ones targeted at schoolchildren were excluded as the CDC’s Division of Adolescent and School Health focuses on these. Substance-abuse and needle-exchange programmes were excluded because they “are not supported by CDC prevention funds”, though reductions in injecting and needle-sharing were allowed as outcomes in programmes targeting drug users.

Media interventions delivered to the community were excluded. Lyles and colleagues identified ten of these that satisfied CDC criteria, and they will be evaluated in a forthcoming review.

Criteria for inclusion

Studies had to be:

  • Published in the USA between 2000 and 2004
  • Present outcome data on “HIV testing behaviour or sexual or drug-injecting behaviour that directly impact the risk of HIV transmission”
  • Have at least one outcome measure that was statistically significant (p=≤0.05)
  • Had no measure that displayed a statistically significant negative outcome
  • Had at least 50 subjects (the minimum number was in fact 175)
  • Had a control arm
  • Measured outcomes at least three months after the end of the intervention
  • Had, at this point, a ‘lost to follow-up’ (drop-out) rate of no more than 30%
  • Analysed all participants regardless of their degree of prevention exposure (i.e. was an ‘intent-to-treat’ analysis).

Importantly, the CDC did not rank programmes according to their degree of effectiveness, because outcome measures were so heterogeneous.

What they taught

Most interventions included skills building of some kind. These included:

  • Setting goals for risk reduction (16 interventions)
  • Condom technique (14 interventions)
  • Interpersonal skills such as disclosure, assertiveness and communication (13 interventions)
  • Personal ones such as problem solving and decision making (10 interventions)
  • Stress relief (six interventions, including three out of the four targeted at people with HIV)
  • Help with isolation and getting better social support (five interventions)
  • Sexual abstinence (two interventions, both targeting African-American youths)


Half of the 18 programmes targeted heterosexual adults, five drug users, three ‘high-risk’ youths and three gay- and non-gay-identified men who have sex with men (MSM). These are not mutually exclusive; some targeted several categories. Four exclusively targeted people with HIV, of which one targeted all adults, one heterosexual adults, one MSM and one high-risk youths who used recreational drugs.

Thirteen of the studies had more than 50% ethnic minority subjects, and seven were exclusively for racial minorities (four for African-Americans, one for Hispanics and one for both). Eight studies exclusively targeted women and one targeted women and their male partners. Nine out of 10 programmes reporting the socioeconomic status of participants had a majority of unemployed subjects.

All of the programmes relied on at least one theory of behaviour change (data available). Seven programmes were sited at clinics, five in community venues or public areas and three in community-based organisations. Fourteen were led by a professional of some sorts – therapist, counsellor or facilitator – while six were peer-led (again not exclusively). Most interventions had a range of between nine and 18 hours of subject participation, delivered in 4-9 sessions, though one consisted of a one-hour intervention and one of 32 hours.

What changed

Studies reported on a whole variety of outcomes, none exclusively, and no study included all outcomes included by the CDC.

Twelve studies reported a significantly reduced frequency of unprotected sex in participants, and all three studies targeting MSM reported significantly reduced unprotected anal or receptive anal intercourse. Eight studies reported increased condom use. Four out of five studies reporting risk in drug users reported significantly reduced sexual risk behaviour and three reported reduced injecting or needle-sharing.

Four reported a significantly reduced incidence of sexually transmitted infections in the twelve months after the study and three reported a significantly reduced reduction in the number of partners. However only one study reported on the bottom line of HIV prevention, namely HIV incidence. This, the EXPLORE study, was able to do so because it was by far the largest study, recruiting 4295 gay men or 4.5 times as many as the next-largest study. It randomised the subjects into normal monitoring versus monitoring plus a series of one-to-one coaching interviews with a counsellor. It produced a modest (18%) reduction in HIV incidence which was not statistically significant, though larger reductions took place in unprotected anal sex and STI acquisition.

One study has already cleared all the CDC hurdles and is now available as a standard package or ‘franchise’ for trainers and agencies to apply to run. This is the ‘Healthy Relationships’ course devised by Professor Seth Kalichman. One of the programmes targeted at people with HIV and applicable to all adults, it helps people with HIV cope with stress, disclose HIV status to partners, family and friends, and build healthier and safer relationships by using modelling, role-play, and feedback to participants and using movie clips to set up scenarios about disclosure and risk reduction.

Another eleven programmes have been retained from the former PRS Project compendium, making a total of twelve packages targeted at various populations. You can find details of all these programmes and how to apply to run them at Six more of the programmes in the present review are currently going through the packaging and dissemination process.

There are significant gaps in the CDC’s review of what works in HIV prevention programmes. Firstly, they only review US-based programmes and what works in the American cultural context may not work in other countries. Secondly most intervention studies only took place in one setting and often at only one site, and it is uncertain how generalisable they are either in terms of varying the setting or the target group.

Thirdly, significant groups of people have not been addressed by many of these interventions. These include minority MSM, particularly young minority MSM, though a study presented at Toronto (see this report) may help rectify that gap. Other populations not addressed include transgendered persons, intravenous drug users with HIV, and rural populations (all studies took place in cities with the exception of one study among drug users in rural Puerto Rico).

HIV prevention programmes generate, as the researchers comment, “a vast and heterogeneous literature” in a field where there are no protocols or best-practice guidelines to rely on. The CDC are at least attempting to inject some theoretical rigour and evidence into an inherently ‘fuzzy’ area of HIV research.


Centers for Disease Control and Prevention. Compendium of HIV prevention interventions with evidence of effectiveness. Last updated 7 January 2000. See

Lyles CM et al. Best-evidence interventions: findings from a systematic review of HIV behavioral interventions for US populations at high risk, 2000-2004. American Journal of Public Health, 47(1). Early online edition. 2007.

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