With an already strained vaccine supply, Pima County is seeing delayed COVID-19 vaccine appointments as shipments of doses are slowed due to harsh winter weather conditions across the U.S.

The county says the appointments at risk of being delayed include some second dose vaccine appointments at Tucson Medical Center beginning Feb. 18, as well as appointments at Tucson Convention Center and Banner South beginning Feb. 19.

Two mobile vaccination events set for Feb. 20 have been postponed. The mobile vaccination efforts are targeted to vulnerable populations and will now be held sometime in March, the county announced in a press release.

Further complicating vaccine administration, next week, the county will only receive 12,500 doses for all county-run vaccination sites.

This represents the lowest total of weekly doses allocated to Pima County in 10 weeks, according to the press release.

Last week, Pima County's vaccine supply was decreased to 17,850—a 40% reduction from the previous week. This week, the doses were cut down to 16,300 doses of Moderna, while the new University of Arizona POD was given 1,000 doses.

The state is now taking control of all Pfizer allocations, but the county has no insight into what the Pfizer allotment is.

Even though the county recently opened its eligible population of vaccine recipients to the 65+ population, the tight supply is causing the county health department to focus on the second doses needed for complete immunization.

The CDC has announced second vaccine doses can be given up to six weeks after the first dose.

“As we deal with the challenge of this delayed shipment, we are also thinking about how to best use the limited supply we will get next week as well,” Dr. Theresa Cullen, the director of the county health department, said in the press release. “We are starting to receive fewer doses than we received a month ago, meaning that nearly all of our upcoming doses will need to be focused on getting people their second dose.”

While Cullen says the county is poised to deliver second doses, the cut in vaccine supply is causing existing vaccination centers to cut hours and first-dose appointments.

Additionally, mobile vaccination events are being postponed and the county’s community health centers that serve the periphery of the county aren’t receiving additional doses to provide first-time shots.

The Tucson Convention Center is reducing its vaccination hours one hour a day, operating 8 a.m. to 4 p.m. instead of 5 p.m., while the Tucson Medical Center is only providing first-dose appointments to those 75 and older.

The county’s two Banner sites are consolidating their operations on March 4, so both the Banner North and Banner South sites will operate at the Kino Sports Complex. As a result, Banner North has stopped making new appointments.

While vaccine shipments to Pima County have been delayed due to severe winter weather conditions across the nation, Cara Christ, the director of the Arizona Department of Health Services, said the state’s Pfizer vaccines should arrive on time, but the Moderna doses have not yet shipped.

“What we're anticipating right now, given I can't predict the weather, would be that [the Moderna vaccines] probably will arrive at the beginning of next week, because we've heard that they will not ship on the weekends,” Christ said during the opening of the state-run UA POD today.

As vaccine arrival at most of Pima County's vaccination sites is threatened by weather conditions, Christ anticipates UA will continue to be regularly supplied.

“We anticipate getting level supply for the next couple of weeks," she said. "So what we would likely do is keep the number of doses here so that we can make sure that we're meeting all of the appointments that have already been scheduled, then after a couple of weeks, as we anticipate getting more and more vaccine, then we would increase the supplies pro-rata."