Study designs of evaluations included in the review
Only randomised controlled trials (RCTs) were eligible according to the inclusion criteria and listed among the included studies. The results of some non-randomised trials were discussed separately in the narrative synthesis.
Specific interventions included in the review
All types of preventive intervention at the individual, group and community level were eligible for inclusion. The interventions used in the included studies were classified as behaviour change, vaccination, use of topical microbicides, and prophylactic, curative or suppressive therapy.
Participants included in the review
No inclusion criteria for the participants were specified. The participants in the included studies were heterosexual and homosexual men and women. They were recruited from population samples that included people attending STI clinics and their partners, sex workers and the general population. Most of the included studies were conducted in the USA, Africa, Asia or Europe.
Outcomes assessed in the review
The studies were required to evaluate an objective measure related to the prevention of STI acquisition, transmission or complications. Most of the included studies assessed acquisition of STIs or incident infection rates. Some studies assessed intermediate outcomes such as condom use and STI screening.
How were decisions on the relevance of primary studies made?
The authors did not state how the studies were selected for the review, or how many reviewers performed the selection.