Politics of leprosy segregation in Japan: the emergence, transformation and abolition of the patient segregation policy

The segregation of leprosy patients, a practice introduced early in the 20th century, was maintained in Japan after World War II. It locked in the viability of subsequent policy choices, and patients’ isolation was sustained long after it was proven to be scientifically unnecessary. For leprologists and leprosarium directors, there was little opportunity to conceptualize and test the epidemiological validity and effectiveness of outpatient services as alternatives to the existing policy, since most of the patients were already hospitalized. Since leprosy was no longer a threat to the general public, bureaucratic officials, as well as legislators, lacked strong incentives to reformulate the overall policy. Within the Ministry of Health and Welfare, daily tasks were largely transferred to the section for leprosarium management, and the search for other options lost importance. For patients, long institutionalization elevated their dependency on life in leprosaria. These conditions must be emphasized as policy legacies, the results of past policies, since they posed obstacles to effective policy innovation in accordance with changing scientific knowledge. To make policies reflective of scientific knowledge, it is essential to understand and foresee the effect of policy legacy, when introducing and appraising public health policies.