Coronavirus cases continue to rise in California, causing one health expert to warn of a pandemic resurgence.

“We are now in our sixth wave,” said Dr. Sara Cody, public health director and public health officer for Santa Clara County, on May 2. Coronavirus-positive hospitalizations in the county rose from 74 in mid-April to 101 by April 26.

The LA Times reported that, statewide, California’s coronavirus case rate rose 10% between April 27 and May 4, from 5,700 to 6,300. However, the official figures may be under-evaluated due to the widespread availability of at-home tests, which are not reliably reported to health organizations.

While the level of cases was still low, coronavirus-positive hospitalizations rose for eight days, from 950 to a little over 1,100 across the state.

The case rate in Los Angeles County rose by 24% in the week ending May 4, from almost 1,700 to 2,100. This equates to 142 instances per 100,000 people. A rate of 200 or more is deemed high transmission by the U.S. Centers for Disease Control and Prevention.

Still, Los Angeles County Public Health Director Barbara Ferrer said she does not believe the current increases are evidence of a fresh wave or surge. But, she noted, the rise in cases is grounds for concern.

Coronavirus-positive hospitalizations in Los Angeles County remained stable at 248 over 235 the preceding week. Ferrer expressed relief that COVID-related hospitalizations, deaths, and test positivity rates have remained steady despite recent increases in infections.

“There always is a small lag between cases and hospitalizations and deaths,” Ferrer noted during a briefing Wednesday. “But more importantly, we think this reflects the protective effects of vaccinations, boosters, and now, therapeutics.”

Dr. Grant Colfax, the head of San Francisco’s public health department, said last week he was unconcerned by the city’s high case rate, citing the city’s extraordinarily high vaccination and booster rates and low hospitalization rates.

“Our case rate and the number of hospitalizations have increased. But the hospitalizations — and particularly the ICU numbers — have not increased to a degree that we’re concerned about,” Colfax told San Franciso city health commissioners on Tuesday.

The most recent statistics reported on Sunday, May 8, show that California had a statewide daily average of 7,632 positive cases over the past week and an average of 1,410 daily hospitalizations due to COVID.