The child, who was under the age of 5, had underlying health conditions and died last month of complications related to COVID-19, according to the Orange County Health Care Agency.
"My heart goes out to this family who has lost a precious young life. This is an urgent reminder that we must do everything we can to protect our little ones, the children and infants in our community who are not yet eligible for a vaccination," county Health Officer Dr. Clayton Chau said in a press release.
Additional details about the child, such as gender and exact age, were not immediately released.
This is the second pediatric COVID death in Orange County. The first juvenile COVID fatality occurred in August 2020, and that teenage girl had significant underlying medical conditions.
Last month, a child under 12 with underlying health conditions was reported among the COVID-19 deaths in Los Angeles County.
"If anything, this reminds us of how this disease can affect everyone at any age," said Dr. Regina Chinsio-Kwong, the county's deputy health officer.
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Meantime, President Joe Biden is calling on the Occupational Safety and Health Administration to set up a temporary emergency standard that would require companies to ensure workers are vaccinated.
"The president is covering more than 100 million workers with vaccination requirements - 100 million workers, that's two-thirds of our workers in America," said Jeff Zients, the White House COVID coordinator.
There is resistance to the plan. An ABC News/Washington Post poll finds nine in 10 unvaccinated adults oppose employer-led workplace vaccine mandates. And among unvaccinated workers, fewer than two in 10 say they will comply.
"We have to help people feel confident that getting vaccinated is the right choice for them and for their families," said U.S. Surgeon General Dr. Vivek Murthy.
This comes as there is a record number of COVID infections among children. The president toured a school this morning with the secretary of education.
"The safest thing you can do for your child 12 and over is get them vaccinated," Biden said.
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Thursday, LAUSD became the largest district to mandate vaccines for students 12 and older.
"We must do all we can to protect our children and to keep them safe in school for in-person learning," said CDC Director Rochelle Walensky.
Los Angeles county says it re-examined older COVID cases and found evidence of the mu variant appearing over the summer. The good news is the overall numbers are improving and cases are down.
"With our seven-day cumulative case rate now 104 new cases per 100,000 residents, this case rate represents a welcome 35% decrease from last week. This is the third week in a row we've seen decreases in our case rate," said Barbara Ferrer, director of the L.A. County Public Health Department.
Officials say while they're seeing more breakthrough cases, they're still a very small number. Well over 90% of people who are hospitalized with COVID are unvaccinated.
City News Service contributed to this report.
Correction: A previous version of this story stated that the child's death was the first COVID-related pediatric death in Orange County. It is the second, but the youngest.