Abstract: Out of 14,717 citations, only one study met the inclusion criteria. The included RCT recruited women and girl children who received post-exposure prophylaxis (PEP) after rape from sexual assault services in South Africa between August 2007 and May 2008. Participants (n (number) =274) were randomised into a telephone support (n=136) and control (n=138) group. Control group participants received usual care (an interactive information session) from the sexual assault service during the 28 days in which they had to take PEP, with no further contact from the study staff. Telephone support group participants received standard care and phone calls from a counsellor throughout the 28 days when they had to take PEP. Overall, adherence to PEP was not significantly (P=0.13) different between the intervention (38.2%) and control (31.9 %) groups. Also, the proportion of participants who read a pamphlet, did not return to collect medication or with a depression were not significantly different between the intervention and control groups (P=0.006, P=0.42, P=0.72 respectively). The proportion of participants who used a diary was significantly (P=0.001) higher in the intervention group (78.8%) versus the control group (69.9%). The study authors reported that there were no recorded adverse events. The RCT did not provide information about participants’ and providers’ evaluation outcomes, or economic outcomes. The study had a moderate risk of bias. We found only one RCT, with a moderate risk of bias, which showed that providing PEP support by phone calls did not result in higher adherence to PEP. However, the RCT was conducted in an upper-middle-income country with high HIV prevalence, on a high-risk population and the applicability of its results on other settings and contexts is unclear. There is a need for robust evidence from various settings on the effectiveness of using phone calls for providing PEP support and for other HIV prevention interventions.

Plain-language summary: The aim of this review was to assess the effectiveness HIV prevention interventions delivered by phone calls compared to the standard way of delivering care. After a comprehensive search of various scientific databases and other resources, we found only one relevant study. This study was done in sexual assault services in South Africa. Study participants were women and girls who were given medication to prevent HIV infection (so called 'post-exposure prophylaxis' or 'PEP') after they had been raped. The participants were divided into two groups: one group of participants only received standard care and participants in the other group were given standard care and support via telephone calls to help them take their HIV prevention medication. Overall, only about one third of the participants took their HIV prevention medication for 28 days. The participants who received the phone calls were not more likely to take their medication than participants who only received standard care. Also, the phone calls did not decrease the number of participants with depression and did not increase the number of participants who read an information pamphlet or returned to collect HIV prevention medication. Only a higher percentage of participants who received the calls used a medication diary compared to the participants who did not receive the calls. No harmful effects of this intervention were reported. We could not find any information about other relevant outcomes, such as participants’ and healthcare providers’ satisfaction with the telephone intervention or costs. We urgently need more studies conducted in various settings comparing the effectiveness of the phone calls to other ways of delivering HIV prevention interventions to prevent new HIV infections.