Large review finds some evidence that peer support is beneficial in HIV care

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A review of the evidence for peer support has found that retention in care, antiretroviral therapy (ART) adherence and viral suppression may be improved for those involved in peer support programmes compared to those who were not. Dr Rigmor Berg of the Norwegian Institute of Public Health showed that peer support may be helpful for these three outcomes, but found no compelling evidence for the other psychosocial and medical outcomes that they were evaluating.

Peer support programmes are meant to encourage equals to support one another in living with HIV and are well established in HIV care. The aim is to provide social and emotional assistance, help with daily management, access to community resources and ongoing support with a chronic disease. Peer support is well established in many places, but the evidence base for it is limited, so the researchers wanted to assess how effective it really is.

"Many of the studies showed a variety of results which need to be interpreted with caution."

The review, published in PLoS ONE, identified 20 randomised controlled trials which were looking at the effectiveness of peer support interventions. To be included, studies had to have a minimum of one hour of interaction in person from a peer living with HIV. All study participants were at least 18 years old. The studies were conducted in nine different countries with half of the studies from the USA and other studies from Nigeria, Uganda, South Africa, Vietnam, Kenya, China, Mozambique and Spain. The studies had seven main outcomes including retention in care, ART initiation, ART adherence, CD4 cell count, viral suppression, quality of life and mental health. Additional outcomes evaluated were adherence to care, risk behaviours and stigma.

A variety of populations were included in the final papers chosen with three programmes aimed specifically at men who have sex with men, another three including transgender people and another one aimed at women, however there were no studies involving sex workers. There was a mixture of people newly starting ART and people already on ART. The researchers aimed to pool papers together for comparison with similar endpoints to increase the validity of the results.

When examining five studies looking at retention in care in those enrolled in peer support interventions compared to those who were not, there was statistically significant evidence from these studies at 12 months showing a slight improvement in retention. The results at six months were however very different between different studies and the researchers themselves conclude that “the result must be interpreted with caution”.

Eight of the studies from a multitude of countries were compared for ART adherence over a 3-12 month follow-up period. Generally, adherence was defined as having taken at least 90% ART in the previous week and found that peer-support encouraged ART adherence. However, similarly to the studies looking at retention, there was a lot of differences between the studies and these results should also be “interpreted with caution”.


retention in care

A patient’s regular and ongoing engagement with medical care at a health care facility. 

virological suppression

Halting of the function or replication of a virus. In HIV, optimal viral suppression is measured as the reduction of viral load (HIV RNA) to undetectable levels and is the goal of antiretroviral therapy.

statistical significance

Statistical tests are used to judge whether the results of a study could be due to chance and would not be confirmed if the study was repeated. If result is probably not due to chance, the results are ‘statistically significant’. 


Social attitudes that suggest that having a particular illness or being in a particular situation is something to be ashamed of. Stigma can be questioned and challenged.


When the statistical data from all studies which relate to a particular research question and conform to a pre-determined selection criteria are pooled and analysed together.

Neither of the two studies examining ART initiation found any statistically significant data to support the use of peer support interventions to encourage people living with HIV to start ART treatment. Similarly, the five studies examining CD4 cell count were too different to compare and there was no statistically significant difference between the group who were involved in a peer-support intervention and those that were not.

Viral suppression was generally considered to be below 100 copies/mL and there were eight different studies looking at this end point. The results varied a lot between studies, and many were too different to be compared with one another. Some were positive for peer support and when the researchers combined the data from two studies to compare viral loads after 24 months, it showed that participants were almost twice as likely to have a suppressed viral load as those not involved in peer support programmes. Most of this data was from a large Ugandan study, whereas the smaller study from Vietnam did not show similar convincing evidence that peer support encouraged viral suppression.

There were only three studies looking at quality of life and these did not find convincing evidence that peer support improved the quality of life for people living with HIV. The two studies looking at how peer support groups affected mental health did not provide convincing evidence to support the use of peer support interventions, even though generally there were more favourable mental health outcomes for those involved in peer support groups.

The other additional outcomes examined also showed there was no evidence that peer support decreased stigma, increased adherence to care or decreased high risk behaviours for the spread of HIV, such as unprotected anal intercourse.

Pooling the data together in this review was often difficult, making the results of meta-analysis difficult to interpret. The nature of peer support interventions and their use in different contexts makes it hard to form direct comparison between studies.

While there is some evidence that peer support may improve retention in care, ART adherence and better viral suppression, many of the studies showed a variety of results which need to be interpreted with caution. The researchers concluded that “The modest but important improvements in outcomes suggest that peer-support be considered as a treatment approach to support existing HIV care services.”


Berg RC et al. The effectiveness of peer-support for people living with HIV: A systematic review and meta-analysis. PLoS ONE, 16: e0252623, 2021 (open access).