The choice of screening programme will have implications for the resources required and the potential reach and effectiveness of the programme. The decision on which model to use should be based on determining which approach will be most effective for reaching the targeted risk group with the resources available. The effort and resources required to reach the target population can be limited by screening in locations where people gather for other purposes, such as health centres or workplaces, although not all populations can be reached in this way.
Programmes that bring screening to places where people live or work can reach more vulnerable populations, particularly those for whom there are barriers to accessing care, but these programmes require more resources. Such programme models can include continuous community-based case finding or periodic event-based case-finding (27). Examples include home visits, mobile outreach screening campaigns, community-based screening events with or without door-to-door mobilization, such as health fairs, and differentiated service delivery events, such as ART adherence meetings. Fig. 2.4 shows different forms of screening programme models.