CDC advises masks for unvaccinated students, staff. But Arizona schools can't require them Yana Kunichoff, Arizona Republic New COVID-19 guidance from the Centers for Disease Control advising unvaccinated students and staff to continue to wear masks inside school buildings, particularly young students, won’t become official policy in Arizona, where the Legislature has prohibited districts from mandating masks. The discrepancy between the Legislature’s law and the federal public health guidance has alarmed some Arizona health practitioners and parents, who argue that the growing threat from the coronavirus' delta variant, and Arizona residents’ slow vaccination rates, could increase the spread of the virus this fall.