The Department of Health and Human Services is a government agency that protects the lives of citizens of the United States. The department is comprised of more than 11 agencies, including the Office of the Secretary, Administration on Aging, Administration for Children & Families, and Agency for Healthcare Research & Quality. Through its agencies, the Department of Health and Human Services performs research on health and social science. The department also provides immunization, financial assistance and educational services. It specializes in substance abuse treatment and prevention and food and drug safety programs. The department additionally offers the Medicare program, which is one of the leading providers of health care insurance in the United States. The Department of Health and Human Services supports the Head Start programs, as well as several faith-based and community initiatives.