By CBSLA Staff

LOS ANGELES (CBSLA) — The Los Angeles County Department of Public Health Thursday reported 506 new COVID-19 infections, the highest daily number of new cases since mid-April and more than double the average daily number reported in mid-June.

Masked and unmasked people make their way through Grand Central Market in Los Angeles, California on June 29, 2021 as World Health Organization (WHO) urges fully vaccinated people to continue wearing masks with the rapid spread of the Delta variant. (Photo by Frederic J. Brown/AFP via Getty Images)

The high number of cases continued the county’s upward trend that began after statewide lifting of health restrictions and could be driven in part by the spread of the highly-contagious Delta variant.

READ MORE: Animal Cruelty Charges May Be Sought After Severely Neglected English Bulldog Puppy Found At Coachella Property Dies

Health officials also said the county’s daily positivity rate held steady at 1.2% Thursday, but that was triple the 0.8% rate reported last Friday.

As of Thursday, there were 280 COVID-19 patients hospitalized, 74 of whom were being treated in intensive care units.

County Public Health Director Dr. Barbara Ferrer said the recent increases in both cases and hospitalizations appeared to be concentrated largely in the Black community, which also has the lowest rate of vaccination.

Ferrer said the disproportionate impact was a “cause for alarm,” that required “strategic actions.”

READ MORE: Sean Penn Refuses To Return To Set Unless Crew Fully Vaccinated

However, she also said the upward trend in cases and hospitalizations has thus far not led to a corresponding increase in deaths. On Thursday, public health reported six new deaths, bringing the countywide death toll to 22,489.

The increases come amid growing national concern about the Delta variant, first detected in India, which is believed to be far more contagious, though it was not immediately known if it caused more severe illness.

Locally, there have been 245 confirmed cases of the Delta variant, nearly double the number from last week, an increase that Ferrer said made clear there was “increasing circulation” in the community.

And while she again stressed that existing vaccines provided strong protection, including against the Delta variant, breakthrough infections do happen.

According to data released Thursday, there have been 2,190 documented breakthrough infections in the roughly 4.5 million county residents who are fully vaccinated, for an infection rate of 0.048%. Of the fully vaccinated people who got the virus, 192 were hospitalized and 20 died.

MORE NEWS: Remains Found In Ballona Wetlands ID’d As Missing Woman Kolby Story

(© Copyright 2021 CBS Broadcasting Inc. All Rights Reserved. City News Service contributed to this report.)