CALIFORNIA STATE HEALTH OFFICIALS ARE MONITORING 8,400 CASES OF THE NOVEL CORONAVIRUS. “All of these people have travel history from China, but are not currently showing symptoms. Those individuals have been advised to stay in their homes for 14 days, the recommended incubation period for the virus. 28 of the confirmed cases currently reside in California. The other five have left the state, Newsom indicated. It’s unclear whether the 33 cases are from the evacuated Diamond Princess cruise ship that was quarantined off the coast of Japan. California health officials have 200 testing kits on hand and will be receiving more next week, according to Newsom.