More than 21,000 Californians have now tested positive for coronavirus, while the death toll from the illness across the state approaches 600 people.

According to data compiled by this news organization from county health departments throughout California, 594 people with confirmed cases of COVID-19 had died as of Friday evening. That marked an increase of 49 deaths over Thursday, a 9 percent climb.

In all, 21,336 people have tested positive for coronavirus in California, up 5.9 percent from the day before.

There have been 4,724 cases and 129 COVID-19 deaths in the Bay Area’s 10 counties. Those figures represent a 4.8 percent increase in cases, and an 8.4 percent increase in deaths.

Public health officials caution that because testing for the deadly illness remains limited and many who have coronavirus never show symptoms, the number of confirmed cases under-counts its actual spread in the community.

Still, Gov. Gavin Newsom and others say the number of cases and deaths has been lower than many feared when California and the Bay Area emerged as an early center of the American coronavirus outbreak several weeks ago. Although COVID-19 still has not reached its peak in California, officials credit strict orders that have shut down businesses and kept residents sheltered in their homes with slowing the virus’ spread and limiting its toll.

“This is actually signaling to us that our peak may not end up being as high as we planned around and expected,” said Dr. Mark Ghaly, secretary of the state’s Health and Human Services department. “And the difference between what we’re seeing today in our hospitals may not be that much different than where we are going to peak in the many weeks to come.”

While state officials are feeling optimistic about those projections, they are also scrambling to address alarming outbreaks at nursing homes, whose residents are among those most vulnerable to COVID-19. Nine deaths have been reported at a single Hayward facility, where 66 residents and staff have tested positive for coronavirus; another facility in Orinda has reported three deaths and 51 confirmed cases.

Newsom released data Friday showing 1,266 people who live at or work in 191 skilled nursing facilities statewide have tested positive for coronavirus. He also said state “SWAT teams” of infectious disease specialists and additional staff would be dispatched to homes that are struggling to contain the virus.

“This state has a disproportionate number of aging and graying individuals, and we have a unique responsibility to take care of them and their caregivers,” Newsom said.