Smartphone COVID-19 exposure alert system signs up 4 million Californians

California's smartphone-based COVID-19 exposure alert system had racked up 4 million sign-ups by Friday afternoon, according to the state Department of Public Health, but needs more residents to opt in to be effective.

The system, dubbed CA Notify, officially launched Thursday and builds off of traditional contact tracing methods by sending smartphone alerts to people who've spent prolonged time with someone who later tests positive for the novel coronavirus.

Public health officials hope the tool will help slow the spread of the virus by providing people with timely information so they can self-isolate and get tested for the disease.

However, the system still needs a lot more of California's 39.5 million residents to opt in, officials said. It launched as coronavirus cases are surging throughout the state.

On Saturday, San Diego County public health officials reported 2,490 new positive cases and 14 additional deaths.

The surge continues to stretch ICU capacity thin.

On Saturday, the California Department of Public Health said the available ICU capacity in the entire Southern California region was just 5.3%, and in the San Joaquin Valley region, officials reported there is no ICU capacity left.

San Diego County health officials reported Saturday that 84% of ICU beds were full, a day after warning that the remaining open beds did not have enough staff available to maintain state-mandated nurse-patient ratios.

The San Diego County Sheriff's Department reported a new outbreak in a county jail Friday night, with 54 inmates at the South Bay Detention Facility testing positive for the novel coronavirus, according to a news release. That's in addition to the 370 confirmed cases among inmates in the county's jails since the pandemic began.

The Sheriff's Department said it's taking additional steps to increase social distancing following the outbreak, prohibiting the use of common areas, expanding the use of N-95 masks and restricting the movement in seven county jails.