Evaluation of the national strain typing service for tuberculosis
The National Tuberculosis (TB) Strain Typing Service (STS) was established by the Health Protection Agency (HPA) as a result of the re-emergence of TB as a public health issue in the UK. It is a three-year initiative to provide DNA fingerprinting of Mycobacterium tuberculosis isolates from every TB case in England. The TB STS aims to prevent the spread of TB by better targeting of public health control activity (contact tracing and cluster investigations), by allowing the detection of recent transmission, and by ruling out assumed links between clustered cases where true links do not exist.
The HPA has convened an independent Evaluation Group to conduct a full evaluation of the service and its impact on public health and TB control. The evaluation will consist of five main components: a descriptive component outlining the structures and processes comprising the STS; a before-after survey of service users (TB nurses, physicians and Health Protection Unit staff); an investigation into the usefulness of strain typing for identifying false positive TB diagnosis; a mathematical model of disease transmission; and a cost effectiveness model.