The largest ever meta-analysis (study of studies) of HIV-prevention
the effects of 354 HIV-prevention interventions and compared their effect with
the results for 99 control groups within 33 countries over a 17-year span
(though three-quarters of studies were US-based).
Altogether, 104,054 people took part in the HIV-prevention
programmes, while another 34,751 were included in control groups. (The number
in control groups was smaller because many studies compared the effect with
matched cohorts or historical controls).
About 45% of participants were men (allowing for a few
studies in which gender was not identified); their average age was 26 and 34%
were white, 47% Afro-American or African and 13% Latino. Only 36% of
participants had completed high school.
Many studies did not record which risk groups participants
belonged to, but 11% were designed specifically for gay men, 15% for injecting
drug users, 17% for multiple-partner heterosexuals, 14% for recreational drug
users and 8.5% for sex workers (programmes could target more than one risk
group). Fifty-five per cent of participants reported multiple partners.
Of note, very few studies recorded the HIV status of
participants, possibly because of a presumption that participants were
negative, although in studies where serostatus was recorded, it was 20%.
Before the interventions, 64% of participants ‘never or
almost never’ used condoms, 34% ‘sometimes’ used them and only 2% ‘always or
almost always’ used them. The total proportion of acts of intercourse in which
condoms were used was 32%.
The size of the meta-analysis allowed Albarracin and
colleagues to calculate the effectiveness of prevention interventions for
particular groups of people, both in terms of demographic characteristics like
gender, age and race, and in terms of risk category.
It also enabled them to calculate the effectiveness of specific
kinds of intervention well enough to provide a set of ‘decision trees’ at the
end of the study to help prevention workers decide on the best kind of
intervention for a specific group in future.
There was one important limitation to Albarracin’s survey: she
only used condom use as her primary endpoint. She did not, therefore, include
studies which had other aims, such as abstinence, sexual delay or reduction in
the number of partners, nor did she look at the ultimate effect, HIV incidence.
However, the size of the study did allow her to calculate also
the effectiveness of programmes on intervening effects between the
intervention and the condom use. In other words, she did not just measure the
effect programmes had on condom use
– she was able to categorise the programmes
into the kind of changes of knowledge, skills and motivation they attempted to
This is important because it is an aid to theoretical rigour
of design. An intervention may be based on one of the theories outlined below
and produce a positive result; but without measuring how participants’
psychological attitudes have changed, it leaves open the possibility that the
change in condom use is due to other factors, such as the introduction of
treatment. Or it could find out that the intervention did indeed produce the
desired psychological effect
– but that this change had a negative effect. This
was what seemed to happen with threat-inducing arguments.
Albarracin analysed interventions according to the following
categories (many studies would use more than one method):
– containing arguments designed to
induce a positive attitude about using condoms (48% of programmes)
– containing arguments designed to
increase social responsibility or increase perceived peer-group or societal
pressure to use condoms (15% of programmes)
– containing verbal training or
arguments designed to improve participants’ condom-using behaviours (20% of
- ‘behavioural skills’
– containing training helping
participants to practise behavioural skills (22% of programmes)
– containing “persuasive arguments
designed to increase perceptions of threat [of HIV infection or poor sexual
health] among recipients” (47% of programmes)
- most programmes (94%) provided information about
- 22% of programmes distributed condoms to
intervention groups and 7% to control groups
- 18% of programmes administered an HIV test
- 49% included ‘active’ interventions, such as HIV
counselling and testing and behavioural-skills training
- Two-thirds of interventions (where it was
recorded) were delivered to groups, 20% to individuals and 8% to both
- 30% were delivered in clinics, 31% in schools,
21% in community venues such as the street, community centres or gay bars, and
just 3% consisted of a mass communication.