As the C.D.C. relaxes guidelines for schools, officials in New York City and California are sticking with their mask mandates.

U.S.|As the C.D.C. relaxes guidelines for schools, officials successful New York City and California are sticking with their disguise mandates.

• July 13, 2021, 7:28 p.m. ET

The Centers for Disease Control and Prevention issued caller schoolhouse guidance connected Friday, calling for a afloat instrumentality to classrooms successful the autumn and recommending that masks beryllium optional for afloat vaccinated students and staff.

But the guidance near a batch of details up to authorities and section governments, advising districts to usage section coronavirus information to usher decisions astir erstwhile to tighten oregon unbend prevention measures similar masking and carnal distancing. It besides recommended that unvaccinated students and unit members support wearing masks.

In New York City, the nation’s largest nationalist schoolhouse district, Mayor Bill de Blasio said connected Monday that masks volition inactive beryllium required for everyone successful the upcoming schoolhouse year, though helium added that officials would proceed to measure the decision.

“For now, presume we’re wearing masks, but that could alteration arsenic we get closer,” Mr. de Blasio said astatine a news conference. “But we’ll beryllium driven by, you know, the information we spot and, and the subject arsenic always.”

California besides announced that it volition proceed requiring masks successful nationalist schools, a argumentation that has been successful spot since February and was reiterated successful recently issued guidance released connected Monday for K-12 nationalist schools.

But connected Monday, California officials concisely went a measurement further erstwhile it was announced that “schools indispensable exclude students from field if they are not exempt from wearing a look covering nether California Dept. of Public Health guidelines and garbage to deterioration 1 provided by the school.”

The announcement created disorder astir whether it marked a alteration successful however disguise rules would beryllium enforced successful schools and what the state’s relation mightiness beryllium successful that enforcement, the state’s wellness and quality services secretary, Mark Ghaly, said successful an interview.

Within hours, that connection was removed, and updated guidelines were released again, omitting the notation that schools “must exclude” students who garbage to deterioration masks.

Mr. Ghaly said masks volition proceed to beryllium required successful schoolhouse settings, but however that mandate volition beryllium enforced volition beryllium up to schools’ ain discretion, a continuation of a argumentation from the erstwhile world year.

“I deliberation the astir important happening to accidental is that California is starting the schoolhouse twelvemonth with each of our students masked,” Mr. Ghaly said.

Health officials volition proceed to show information and revisit whether to easiness oregon support its disguise mandate successful schools nary aboriginal than Nov. 1, helium said.

The taxable of schoolhouse closures and reopenings has been peculiarly contentious since the onset of the pandemic, and advising districts has been a pervasive situation for the C.D.C.

Earlier this month, the C.D.C. issued guidance urging schools to afloat reopen successful the autumn and called connected section districts to usage section coronavirus information arsenic guidance for nationalist wellness measures.

The bureau continues to urge 3 feet of societal distancing successful classrooms, but successful a departure from erstwhile guidance, it says that schools tin besides harvester different strategies, similar indoor masking, investigating and enhanced ventilation, if specified spacing would forestall schools from afloat reopening.

In different shift, masks are not mandatory for those who are afloat vaccinated, according to the caller guidelines. The C.D.C. continues to urge masks for those who are not vaccinated, mirroring guidance for the wide public.

In California and successful New York City, mean regular cases person accrued successful caller weeks, driven mostly by the Delta variant, present the dominant strain successful the country. But the wide fig of cases remains low, and epidemiologists person said it was improbable that the Delta variant would beryllium anyplace adjacent arsenic devastating arsenic the past 2 waves of Covid-19.