“To protect all patients, communities and personnel from the known and substantial risks of COVID-19, the American Hospital Association strongly urges the vaccination of all health care personnel,” the organization said in a policy statement. “The AHA also supports hospitals and health systems that adopt mandatory COVID-19 vaccination policies for health care personnel, with local factors and circumstances shaping whether and how these policies are implemented.”

“The evidence is clear: COVID-19 vaccines are safe and effective in reducing both the risk of becoming infected and spreading the virus to others,” said Richard J. Pollack, the AHA’s president and chief executive, in an accompanying statement.

The AHA — which represents nearly 5,000 hospitals — is the largest health-care group to endorse mandatory vaccine requirements for health workers. The association had held off formalizing its stance on mandatory vaccinations in recent weeks, even as some health workers sued or protested over hospitals’ vaccine requirements.