Clinical Research Directory

Inclusion Criteria: * Residents of households and noninstitutional group quarters (e.g., homeless shelters, rooming houses, and group homes); * Persons residing temporarily in student dormitories or temporary housing are sampled within the households that they reside in permanently. Exclusion Criteria: * Persons with no fixed household address (e.g., homeless and/or transient persons not residing in shelters); * Active duty military personnel and civilians living on military bases, persons in long-term care institutions (e.g., nursing homes for the elderly, hospitals for the chronically ill or physically or intellectually disabled, and wards for abused or neglected children); * Persons in correctional facilities (e.g., prisons or jails, juvenile detention centers, and halfway houses), and U.S. nationals living in foreign countries.