Postpartum Adherence Clubs for Antiretroviral Therapy: a randomised controlled trial Over the past 20 years there have been major advances in preventing the mother-to-child-transmission (PMTCT) of HIV, and interventions based on this knowledge have resulted in transmission rates <1% in the United Kingdom and Europe, attributable largely to widespread use of combination antiretroviral therapy (ART) in pregnancy. The remarkable effectiveness of these interventions has led many to suggest that the global elimination of paediatric HIV infection may be possible. Towards this, there is particular excitement regarding universal initiation of lifelong ART for all HIV-infected pregnant women following the World Health Organisation's "Option B+" approach, and this strategy has been implemented in many parts of Africa, including the Western Cape Province of South Africa (SA) from July 2013. But despite considerable optimism, more than 300 000 new paediatric HIV infections occur each year around the globe; almost 10% of these are in SA alone. In turn there is growing recognition that the "Option B+" approach must be accompanied by effective and efficient models of care for delivering ART to unprecedented numbers of HIV-infected pregnant women.   For women starting lifelong ART in pregnancy, there is particular concern about the postpartum period (for the purposes of this proposal, this is from delivery until 24 months postpartum) as a time when HIV-infected women are at a very high risk of not taking their medications (non-adherence) and/or dropping out of care altogether (non-retention). Over the last few years there has been growing evidence that the postpartum period is a difficult time for women on ART, but there are few interventions that aim to support HIV-infected women during this time. One of the few interventions for this purpose is the 'Adherence Club' model. In South Africa and most parts of Africa, HIV-infected patients (including pregnant and postpartum women) attend primary care clinics where doctors and nurses focus on the clinical care of individual patients. In contrast to this, the Adherence Club model is operated by community health workers (lay people without clinical training) working from community venues that are located closer to peoples' homes. There is preliminary evidence that the Adherence Club model could lead to better clinical outcomes than standard clinical services, but the observational studies used to generate this evidence have significant methodological flaws.   To help generate robust evidence about the Adherence Club model for managing HIV-infected women on ART during the postpartum period, we plan to enroll 388 HIV-infected pregnant women on ART immediately after delivery. These women will be allocated at random to either attend routine primary health care clinics for their ART during the postpartum period, or to attend an Adherence Club. Women will be followed up by a study measurement team (that operates separately from either of the clinical services) at regular intervals through 24 months postpartum. This measurement team will check the HIV viral loads and administer questionnaires to women who are participating. The primary focus of the study is the retention of women in care, and their adherence to ART, during the 24-month period. There are secondary outcomes related to the acceptability of the Adherence Club model, and also the cost-effectiveness of the model, compared to standard primary care services as the control condition. The Global Challenges Research Fund (GCRF) supports cutting-edge research to address challenges faced by developing countries. The fund addresses the UN sustainable development goals. It aims to maximise the impact of research and innovation to improve lives and opportunity in the developing world.