SAN FRANCISCO (KRON) — Unvaccinated Californians are increasingly testing positive for COVID-19 and landing in hospitals as the state loosens restrictions for the fully vaccinated.

Los Angeles County – one of the hardest hit by the pandemic – is among the locations with suddenly spiking COVID-19 case, The LA Times reports. COVID-19 hospitalizations jumped by 76% in the last month.

“In the current situation, it is really those who are unvaccinated that should be highly concerned,” Dr. Robert Kim-Farley of the UCLA Fielding School of Public Health told the LA Times.

The state maintains that cases among people who are fully vaccinated are rare. Less than a half-percent of recent new COVID-19 cases are in fully vaccinated California residents, The Associated Press reports.

Even so, four out of nine workers who just tested positive at the state capitol were fully vaccinated, prompting the return of a mask mandate in the building.

The delta variant is now the dominant strain moving across the U.S., the CDC said. It is more contagious than the original virus that plagued the country in early 2020.

In the Bay Area, the delta variant is also causing spikes in cases. Nearly 50% of new COVID-19 cases in Contra Costa County have been the delta strain, health officials said.

A school in Novato and the towns of Fairfax and San Anselmo recently had delta variant outbreaks that have since been controlled, Marin County officials said.

In San Francisco, data shows that COVID-19 cases have been steadily increasing since the end of June, however the county does not share how many are confirmed to be the delta variant.

The Associated Press contributed to this report