Three of the largest U.S. medical organizations threw their weight behind new federal guidelines that reject mass quarantines for healthcare workers returning from Ebola-ravaged countries. In a joint statement, the American Hospital Association, the American Medical Association and the American Nurses Association said the guidance strikes the right balance between protecting public health and ensuring healthcare workers are not "unduly" burdened. "This guidance is based on the best available scientific evidence and provides essential information to public health authorities, state governments, hospitals, clinicians and other health care workers about the appropriate monitoring of individuals who may have been exposed or have had direct contact with a symptomatic person diagnosed with Ebola," the groups said Tuesday.