The county lowered the age eligibility from 75 after reviewing the number of appointments that were being made.
The newly available appointments are for the 3,400 slots at the 31 clinics in Hemet, Lake Elsinore, Beaumont, Menifee, Corona, Indio and Perris.
According to the Riverside University Health System, the county has received 241,750 Pfizer and Moderna SARS-Cov-2 vaccine doses, and roughly 91% of that stock has already been administered.
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RUHS Dr. Geoffrey Leung told the board there are ongoing supply challenges, but the county is focused on offering immunizations "to the most vulnerable,'' by which he meant seniors, mainly those over 85 years old.
"We know call center wait times have been long,'' Leung said. "We're increasing staff and improving our technology platform to make scheduling easier.''
The reservation portal to make an appointment for vaccination can be accessed via rivcoph.org/COVID-19-Vaccine. Those who need assistance may also call the county's 211 help line.
Meanwhile, COVID-19 hospitalization rates continue to drop in Riverside County, according to the most recent numbers released by the RUHS.
RUHS officials said Friday that COVID-positive hospitalizations were at 847, down 17 from Thursday, though an additional 11 virus-related deaths were reported. That includes 220 patients in intensive care units, a one-day drop of 23.
The agency does not release updated COVID-19 statistics on the weekend.
The aggregate number of coronavirus cases recorded in Riverside County since the public health documentation period began in early March is 280,170, with a total 3,320 deaths stemming from virus-related complications, according to the RUHS.
Virus-related hospitalizations peaked near 1,700 in the second week of January, officials said.
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The agency said a total of 3,320 deaths stemming from virus-related complications had been recorded as of Friday, compared to 3,309 Thursday. The fatalities are trailing indicators because of delays processing death certificates, and cover three- to four-week periods.
The number of known active virus cases countywide was 48,264 as of Friday, down 2,847 from Thursday. The active count is derived by subtracting deaths and recoveries from the current total -- 280,170 -- according to the county Executive Office. Verified patient recoveries countywide are at 228,586.
The aggregate number of coronavirus cases recorded in Riverside County since the public health documentation period began in early March is 280,170, with a total of 3,320 deaths stemming from virus-related complications, according to the RUHS.
Emergency Management Director Bruce Barton told the Board of Supervisors Tuesday that the county's ICU space remains at 0% capacity, along with the 11-county Southern California region.
The county is still in the most restrictive "purple'' tier of the governor's Blueprint for a Safer Economy framework.
The overall countywide COVID-19 testing positivity rate is 16.6%, down from 20% last week, based on state-adjusted figures.
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The purple tier impacts bars, theaters, museums, indoor recreational facilities and wineries -- all of which are supposed to remain closed. However wineries, like restaurants, can provide outdoor dining, takeout and delivery.
Most retail outlets are limited to 25% capacity, while hair salons, nail salons and barbershops can operate with safeguards in place.
Additional information is available at covid19.ca.gov/safer-economy/.
City News Service contributed to this report.