Administrators at UCI Health said they've been preparing for it over the last six months - a surge in COVID-19 cases after holiday gatherings.
Dr. Sebastian Schubl was named the medical director of the facility.
"We've seen an unrelenting rise in the number of admitted COVID patients for weeks now," Schubl said in a press conference Wednesday.
With this county mobile field hospital fully operational, the first patients were welcomed Tuesday morning, according to a hospital spokesperson.
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Schubl said the hospital was licensed for 40 additional beds.
According to a press release from the Orange County Health Care Agency, the unit is equipped with running water, toilets, showers, generators, lighting and air purifiers.
Schubl said low-acuity patients would receive care there and staffing wasn't an issue.
"We have, I believe, 17 contracts right now with various staffing providers all over the United States. We are paying whatever is absolutely necessary to get the right number of staff here so that we can keep every licensed bed that we have in this facility open in ratio with the appropriate level of therapists, nurses, technologist, everything else that we need to run not just the main hospital, but every additional space that we add at the exact same level of care that we've always done," Schubl said.
A shortage of workers was a problem at Families Together of Orange County in Tustin.
The nonprofit clinic is part of O.C.'s COVID-19 Testing Network.
Administrators tell Eyewitness News, 15% of employees there have caught the virus, forcing the clinic to turn to telehealth.
The medical director of the nonprofit, Dr. Lowell Gordon, said that created a challenge for those working there to provide health care to underserved populations.
"At the end of the day, patients need to be seen. You can't give a vaccine to children over the phone. When babies are sick, you need to look at them. You need to assess them. You need to meet with them and their parents," Gordon said.
According to the clinic's operations manager, Families Together of OC was approved to get 400 doses of the Moderna vaccine to vaccinate staff from this and seven other nonprofit clinics in Orange County. Vaccinations started Wednesday.
On Wednesday, the county reported 2,145 new COVID-19 hospitalizations.
Schubl said if numbers continued rising this way, the mobile field hospital would sit outside UCI Health at least several months.