Over the course of the COVID-19 pandemic, COVID-19 vaccine mandates have been enacted by numerous states and municipalities in the United States, and also by private entities. In September 2021, President Joe Biden announced that the federal government would take steps to mandate COVID-19 vaccination for certain entities under the authority of the federal government or federal agencies. Most federal mandates thus imposed were either overturned through litigation, or withdrawn by the administration, although a mandate on health care workers in institutions receiving Medicare and Medicaid funds was upheld. All federal mandates were lifted when the national emergency was declared to have ended in May 2023. A small number of states have gone in the opposite direction, through executive orders or legislation designed to limit vaccination mandates.