South Africa's National Blood Service says it is working to encourage young people to become regular blood donors. But it faces a challenge in keeping them involved after they finish high school and move on to university or work. The organisation is introducing programmes to help young donors stay connected and continue donating blood wherever they go. This was revealed at the premiere in Johannesburg of Why Blood Matters, a documentary that takes viewers behind the scenes of blood donation in South Africa. Sisi Segalo reports.