Just a guess ... CA does have a statewide DB of ALL vaccinations (I'm sure this is true of most or all US states). Hospitals treating those hospitalized would access that data for treatment and for FDA stats on breakthrough infections. LA County probably accesses gets statistical info (minus HIPAA-protected info like patients' names) from hospitals, and CNN got it from LA County. That nuch I do not think CNN is pulling out of their corporate rectum.
The claim that the US or California or LA County are experiencing a surge in new cases is, however, pulled out of CNN's corporate and the LIEden Administration's bureaucratic rectum.