LOS ANGELES (CNS) — Doses of Pfizer's coronavirus vaccine began shipping out from a Michigan facility Sunday bound for Southern California distribution centers and other locations in the United States, with Southland health-care workers hoping to get their shots in the next couple of days.

The head of the U.S. Centers for Disease Control signed off on the recommendation of an advisory committee Sunday, officially permitting the vaccine to be administered in the United States. It is said to be 95% effective in preventing the coronavirus.

Army Gen. Gustave Perna of Operation Warp Speed told reporters Saturday that UPS and FedEx would be delivering the vaccine to nearly 150 distribution centers across the country.

Los Angeles County expects to receive nearly 83,000 doses of the vaccine this week, with the initial doses distributed to 83 acute-care hospitals for administration to critical frontline workers.

"Los Angeles County is working with a variety of partners around the county in storing and housing the vaccine," the county's health department said Sunday. "In the interest of the safety of the workers at these sites, Los Angeles County is not releasing details about these locations."

UCLA Health officials said they expected to get the vaccines Monday or Tuesday, with shots administered on Wednesday.

"UCLA Health is implementing comprehensive and detailed plans to receive, store and administer COVID-19 vaccinations. We anticipate a limited number of doses arriving in the next day or two, with additional supplies to follow. We have been designated as a regional hub for distribution to other acute-care hospitals," a UCLA Health statement said.

"Based on the phased allocations made available to UCLA Health, we are committed to offering vaccinations in a fair, equitable and orderly manner that prioritizes those at greatest risk, consistent with guidelines established by the U.S. Centers for Disease Control and Prevention as well as the California and Los Angeles County departments of public health. UCLA Health anticipates beginning to inoculate our own frontline health care workers as soon as Wednesday."

Officials with Cedars-Sinai Medical Center said they had no definitive information yet on when they would be receiving the vaccine.

The Pfizer vaccine was co-developed by German partner BioNTech. It needs to be stored at minus-94 degrees Fahrenheit.

Last week, L.A. County Public Health Director Barbara Ferrer said that the county hopes to receive its second allotment of a vaccine made by Moderna — about 250,000 doses, pending FDA approval — around December 20-21. By sending the doses directly to skilled nursing facilities, the vaccine can be administered right away instead of waiting for a federal agreement with CVS and Walgreens to begin on roughly December 28.

Staff and residents of nursing facilities and long-term care facilities will be among the first wave of people receiving the Moderna vaccine.

Ferrer said public health officials Friday began the process of training skilled nursing facility staff on how to administer the vaccination, while noting that those staffers already administer flu vaccines, so it is not a new experience.

The pharmacies, however, will still work through the federal agreement with CVS and Walgreens to provide the vaccine to long-term care facilities.

"Our pharmacy partners ... will continue to roll out as soon as that system is turned on," she said. "They will continue to roll out vaccination opportunities at all the other long-term care facilities, of which there are hundreds here in L.A. County, and we're going to be relying heavily on them to really move that forward very quickly as well."

The county anticipates receiving another 150,000 doses of vaccine by the end of December, followed by weekly allotments of 250,000 beginning in January.

After the distribution of vaccines to health care workers, skilled nursing facilities and long-term care staff and residents is completed, priority will then move to "essential workers" and then to people at highest risk of severe illness from the virus, such as seniors or those with underlying health conditions.

The county's chief science officer insisted Thursday the process will be done equitably based on health priorities, not on power or prominence.

"Equity is a fundamental principle here," Dr. Paul Simon said. "We want to make sure all people have access, and that those that are at greatest risk either because of higher risk of exposure, or greater risk of severe illness because of chronic health conditions or other factors have more immediate access to the vaccine."

Simon conceded that the judgment of who is considered "at risk" could become a matter for debate.

"That probably is going to become an important consideration when we really start to roll things out -- when we move beyond the highest-risk groups into groups where the risks may be a little bit more uncertain or there are larger areas of gray," he said. "And there, I think, we will do our best to prioritize, be as transparent as possible. I don't think we're going to be doing validation checks with each person as they float through the line, so I think there is sort of an honor system to some degree. But we will do everything possible to make sure we are doing this in an equitable manner, tending to the risks and making sure that we maximize the benefits."

The timing of when the vaccine will start to become available to more of the general population remains a mystery. Simon said that while the vaccine offers a glimmer of hope about a potential end to the pandemic and lockdown orders, the county is still in the midst of a dangerous surge in cases, so residents should expect to see restrictions continuing for months.

He said the administration of the vaccine — an effort to vaccinate about 6 million people in six months — will be a "massive undertaking the scale of which many would argue is unprecedented given the time emergency." But he said a major factor in moving the county closer to "herd immunity" and an eventual return to normalcy will rely on people actually agreeing to be vaccinated.

"We recognize many folks have concerns about the vaccines and may be hesitant to be vaccinated," Simon said. "As we implement the county plan to vaccinate literally millions of Angelenos, it will be critically important that we address this vaccine hesitancy with accurate, understandable, culturally sensitive and linguistically appropriate information, relying on trusted community leaders to help deliver these messages."