Vials group and syringe on table with blue background

Arizonans in the highest priority categories of risk or need could get their first doses of COVID-19 vaccine this week.

But they won’t be risk-free for weeks after that. And it won’t be until summer or early fall before everyone who wants to get inoculated will be able to do so.

Pima and Maricopa counties will divide up Arizona’s first allocation of COVID-19 vaccines while rural areas will have to wait a little while longer.

Steve Elliott, spokesman for the state Department of Health Services, said it’s not a question of deciding that urban residents are entitled to a higher priority. He said it’s a matter of practicality.

The first vaccine set to arrive will be from Pfizer, which has to be kept at -70 degrees Celsius – or about 94 degrees below zero on the Fahrenheit scale. That requires access to special equipment.

And then there’s the requirement that shipments come in minimum doses of 975.

“The big lots and handling requirements of the Pfizer vaccine make it better suited to places where many people can be vaccinated in one place in a finite period,’’ Elliot said.

Maricopa County will get 46,800 doses by the end of December, with 11,700 for Pima.

The vaccine developed by Moderna. That needs to be kept only at minus 20 Celsius, or about minus 4 Fahrenheit, more like a regular freezer. Moderna will ship out the vaccine in lots of a minimum of just 100.

State health officials report that 593 health care providers have completed the approval process and are certified to start administering the vaccine when it arrives. Another more than 1,200 are in the pipeline.

They also reported that every skilled nursing facility in Arizona has opted to participate in a program by the Centers for Disease Control and Prevention to provide vaccinations to all residents and staff.

Both of the vaccines require a second dose, within 21 or 28 days, to be fully effective.

Under the state plan, the top priority for immunization will be health care workers, particularly those working directly with patients. Also in the first group will be home health aides, nursing assistants and medical assistants.

After them come residents of skilled nursing facilities and independent and assisted living centers. 

The second-priority people include adults with high-risk medical conditions living in shelters or other congregate living settings.

Then there are the teachers, about 146,000 of them, along with police, corrections officers and other emergency response workers. 

This group also includes others who work at schools including bus drivers, cafeteria workers and front-office staff that deal with children.

After that come workers for utility companies and then people in food industries including those at grocery stores and restaurants, transportation workers like those who drive trucks and buses as well as gas station employees.

Also, in that second group are other “essential workers” which the state says includes everything from financial services to funeral home employees.

The next priority would be nearly 2.3 million Arizonans with underlying medical conditions like obesity, heart diseases and chronic lung disease. Then there are more than 1.2 million Arizonans older than 65 not in high-priority groups.

This category also includes those confined to prisons and jails. But Christ said that inmates who have underlying medical conditions may, on an individual basis, be moved into a higher category.

That leaves everyone else as supplies become available – and as people choose to get vaccinated.

State health director Dr. Cara Christ said that even with a public relations campaign aimed at those who appear most hesitant, she knows there will be those who refuse.

All this assumes that the system of delivering and administering the vaccine works as planned.

“So, it’s really important that everyone continue taking precautions even after being vaccinated to ensure that everyone is protected,’’ Christ said.

She said procedures are being set up to ensure that people come back for the second dose.

Even after everyone who wants to be inoculated is served, that doesn’t end the matter.

“What we don’t know is how long that immunity lasts,’’ Christ said.

She said it could end up being a situation like the flu, where people have to get revaccinated on a regular basis, or whether it will be like the measles where there is a need for a “booster’’ after a certain period of time.

“Those kinds of studies will still be ongoing,’’ Christ said.

Christ said the state has no plans to force the shots on anyone. But she said that employers, particularly those whose workers deal with the public – and especially those who are vulnerable – are free to impose such a requirement.

The government is providing the vaccine without cost to those who agree to administer it. And she said that insurance companies have agreed to waive any out-of-network deductibles as to what providers charge for giving the shots.