MADISON, Wis.— The deputy secretary of Wisconsin Department of Health Services put the state’s coronavirus vaccination plans in simple, yet striking terms Tuesday.

“It will be the most extraordinary public health intervention our state has ever undertaken,” Julie Willems Van Dijk said. “This COVID-19 vaccination planning and dissemination plan is even more complicated than we had ever imagined.”

Once a vaccine from Pfizer, Moderna or other drug makers receives Emergency Use Authorization from the Food and Drug Administration, millions of doses will be shipped across the country. Wisconsin plans to prioritize its first several hundred thousand vaccinations for healthcare providers and long-term care staff. State health officials are preaching patience, as it will take months for the supply to meet public demand for COVID-19 vaccines.

“As supply increases, we’ll widen the criteria for the recommended vaccination to other essential workers and people at high risk of getting sick from COVID-19,” said Dr. Stephanie Schauer, the DHS Immunization Program Director.

Whichever vaccines receive EUA will present massive logistical challenges for local and state health departments. The two leading candidates require multiple injections, and the Pfizer vaccine must be stored at minus-94 degrees Fahrenheit. Willems Van Dijk said dry ice companies in the state would partner with DHS to store those doses on their way to rural and tribal areas that do not have deep freezer capacity.

DHS calls the vaccine rollout an all-hands-on-deck effort. Some Wisconsinites will be skeptical of a vaccine after such a rapid development phase, but the department expects confidence in the vaccine to increase once it becomes available.

“Some people are the first ones to raise their hands: ‘Let me be first in line,’ Willems Van Dijk said. “Other people, with any kind of change, want to wait and see and come in the second or third wave.”

DHS believes the first doses of an approved vaccine could arrive in Wisconsin before the end of the year.