California Gov. Gavin Newsom declared a state of emergency over the rapidly spreading monkeypox outbreak on Monday, the third U.S. state to do so in a matter of days.

Newsom said the emergency declaration would help support the state’s vaccination efforts. Demand for the vaccines has outstripped supply as infections rise. Staff at sexual health clinics and other sites have struggled to keep up with the influx of people seeking the shots.

California is mobilizing personnel from its Emergency Medical Services to help administer the vaccines. Newsom said the state is working across all levels of government to slow the spread through testing, contract tracing and community outreach.

California’s declaration comes after Illinois declared a public health emergency earlier Monday. New York declared a state disaster emergency in response to the outbreak late Friday.

The U.S. has reported nearly 6,000 cases of monkeypox across across 48 states, Washington D.C., and Puerto Rico, according to the Centers for Disease Control and Prevention. The outbreak has spread swiftly since health authorities in Boston confirmed the first U.S. case in May.