Deputy Pedro Romo had been assigned to the Santa Clarita Valley sheriff's station since 2004, the department said on Twitter.
Romo was also a school resource officer at Valencia High School for the past 13 years.
"Please keep his loved ones in your prayers," the Sheriff's Department said.
LAPD loses two more officers to COVID-19
California has administered more than 6 million COVID-19 vaccines, but the rollout has been slow and rocky and demand continues to far exceed supply. The state is in the process of shifting to a new distribution system run by insurer Blue Shield, which will take some decision-making power away from counties.
The state's virus numbers continue to improve. The state's test positivity rate, hospitalizations and deaths are all down. The rate of people spreading the virus to others is now at its lowest in months, Newsom said.
The Associated Press contributed to this report.