Diagnostic target product profiles for trachoma surveillance

The need for interventions against active trachoma has traditionally been determined using the prevalence of clinical signs that are associated with conjunctival Chlamydia trachomatis infection. However, as trachoma prevalence declines, the specificity of these signs for C. trachomatis infection declines; in some places, specificity is low at baseline. In addition, as trachoma becomes more uncommon, training graders to recognize the signs becomes progressively more difficult. The target product profiles in this publication present the minimum and ideal characteristics for diagnostics needed by trachoma programmes to detect evidence of past and/or present C. trachomatis infection at evaluation unit level.