Los Angeles County health officials reported 2,089 new coronavirus cases on Sunday, with hospitalizations rising as the highly contagious Delta variant continues to spread.

There are 716 people currently hospitalized with COVID-19, up from 452 on July 16, officials said. The county also reported four new deaths, bringing the total to 24,628 fatalities since the pandemic began early last year.

On Saturday, L.A. County Public Health Director Barbara Ferrer warned that the Delta variant was “one of the most aggressive and infectious respiratory diseases known and currently makes up over 80% of sequenced cases in L.A. County.”

Although cases remain at a lower point than they have been during any of the previous surges, the rate of increase between July 3 and 16 was 135%.

Ferrer said vaccinations were still the best safeguard against serious illness requiring hospitalization.

“With unvaccinated individuals comprising over 90% of those currently hospitalized, the ability of the three vaccines to protect us from serious illness caused by the Delta variant is well established,” Ferrer said. “If you are eligible but have not yet been vaccinated, please consider getting vaccinated now.”

On Thursday, Ferrer said that over the month of June, the infection rate among fully vaccinated people was about 27 infections per 100,000 people; among those who were not fully vaccinated, it was 125 per 100,000. In the same time period, hospitalizations among the fully vaccinated were 2 per 100,000 people; for those not fully vaccinated, the rate was 11 per 100,000.

“This past year and a half taught us to fear the kinds of increases in COVID cases that we’re seeing now,” Ferrer said, “because waves of cases have always translated into waves of hospitalizations and deaths.”

The county trend mirrors statewide hospitalization figures. From June 22 to July 22, the daily number of COVID-19 patients hospitalized in California increased from 978 to 2,543, a 160% jump, state data show.

Despite the recent jump in hospitalizations, L.A. remains in far better shape than during the fall and winter surge, when an average of about 15,000 new cases were being reported every day, and more than 8,000 COVID-19 patients were hospitalized at times.

Many health experts are confident that California will never see numbers on that scale again, given that more than half of Californians are fully vaccinated.

Although so-called breakthrough cases among vaccinated people have been seen, the rates continue to be much worse among unvaccinated people.

Last week, Dr. Anthony Fauci, the U.S. government’s top infectious-diseases expert, cited studies showing the Pfizer-BioNTech and Moderna vaccines were 95% and 94% effective against symptomatic COVID-19. The single-shot Johnson & Johnson vaccine has been found 72% effective against clinically recognizable disease.

“Infections after vaccination are expected. No vaccine is 100% effective,” Fauci said. “However, even if a vaccine does not completely protect against infection, it usually, if it’s successful, protects against serious disease.”

Across L.A. County, officials are hosting community vaccination events to reach stragglers in areas hit hardest by the pandemic. On Friday, about two dozen people turned up for doses at a clinic in Pico-Union. On Saturday morning, Mayor Eric Garcetti joined L.A. County Supervisor Holly Mitchell, City Councilman Mark Ridley-Thomas and state Sen. Sydney Kamlager at a community vaccination event in Leimert Park — where 59.5% of people 16 and older have received at least one dose, according to county data.

Racial disparities in vaccination rates remain pronounced countywide. Among Latinos, 55% have received at least one dose, compared with 66% of white residents. In the Black community, that number is 46%.

“Our community, especially Latinos, they need to get in the queue to get vaccinated,” L.A. County Supervisor Hilda Solis said. “I’m very disappointed that we have such low rates of participation in terms of the vaccine.”

Solis also urged county residents to get tested amid rising case numbers.

“There are a lot of people that have the Delta variant and may not know that they are either carriers or that they are experiencing symptoms,” Solis said. “They may think it’s a cold, and that’s why I believe it’s very urgent to be tested.”

Times staff writers Rong-Gong Lin II and Luke Money contributed to this report.