Per the California Department of Public Health website:
"To protect public health, I as State Public Health Officer and Director of the California Department of Public Health order all individuals living in the State of California to stay home or at their place of residence except as needed to maintain continuity of operations of the federal critical infrastructure sectors, as outlined at https://www.cisa.gov/identifying-critical-infrastructure-during-covid-19."
Full details at: https://www.cdph.ca.gov/Programs/CID/DCDC/Pages/Immunization/ncov2019.aspx