South Dakota's top three health systems say they will require annual flu vaccinations for all employees, healthcare providers and volunteers.
Sanford Health, Avera Health and Regional Health say the decision was made to maximize patient safety and protect employees against the disease.
South Dakota last year had its highest number of flu deaths since 2004 with 37.
Avera chief medical officer David Erickson says vaccinations combined with good hand hygiene and covering coughs can help reduce the spread of the flu.
Sanford Health is based in Sioux Falls and Fargo, N.D. Avera Health is based in Sioux Falls. Regional Health is based in Rapid City.