South Africa's anti-retroviral programme to treat HIV infection is the largest in the world with 5.5 million people in treatment. It’s transformed this disease from an automatic death sentence, to something that can be managed as a chronic illness and the government is determined to expand the programme and get more people with HIV in treatment. It’s an ambitious plan and Claudia Hammond hears how psychological tools called "nudges", drawn from behavioural economics, are being used and tested as low-cost interventions to persuade more people into treatment. Dr Sophie Pascoe, Co-Director of South Africa’s first HIV nudge unit, Indlela, describes how the new techniques are being used. And the plight of the Covid-19 shielders. Shannon is so vulnerable to catching the virus that she has lived apart from her husband and teenage daughter for almost two years. What’s it like having your life on hold and not being able to hug or kiss your loved ones? And Matt Fox, Professor of Global Health Epidemiology and Boston University joins Claudia to discuss the increase in cholera outbreaks and the shortage of vaccines and the new UK trial to manufacture blood in a laboratory. Image: Beaded HIV/AIDS ribbon brooch among beaded South African flag keyrings, Eastern Cape Province, South Africa. Credit: Neil Overy/Getty Images) Presenter: Claudia Hammond Producer: Fiona Hill