Pima County Health Department

Pima County Health Department Director Dr. Theresa Cullen said reductions in state-allocated vaccines could lead to tough decisions on slowing first-dose vaccinations.

The county's current vaccines – Pfizer and Moderna – require two doses. Cullen said the county could face a situation where tight allocations would limit the first-dose capability to ensure those waiting on a second dose get them within recommended intervals.

"We are planning for that inevitable time when we need to expand so people could get their second shot," she said. "But if the immunization numbers are decreased, then maybe, we're in a situation where we're going to decide whether to do the first or the second shot."

Cullen said the CDC had given institutions the latitude to stretch a second shot out to six weeks, but not beyond that point.

She did say a potential Johnson & Johnson's vaccine could help relieve stress on vaccination sites since it's a single dose and better suited for doctor's offices and providers without the same cold storage requirements as Moderna and Pfizer.