Dr. Anthony S. Fauci mentioned on Sunday that he was open to stress-free indoor masking guidelines as extra Individuals get vaccinated towards the virus, simply two days after the Facilities for Illness Management and Prevention belatedly emphasised the hazard of airborne transmission.

Dr. Fauci, President Biden’s chief medical adviser for the pandemic, mentioned that as vaccinations climb, “we do want to start out being extra liberal” when it comes to guidelines for carrying masks indoors, although he famous that the nation was nonetheless averaging about 43,000 instances of the virus every day. “We’ve received to get it a lot, a lot decrease than that,” he mentioned.

On Friday, the C.D.C. up to date its steering about how the coronavirus spreads, stating explicitly that people can inhale airborne virus even when they’re greater than six toes away from an contaminated particular person. Beforehand, the company had mentioned that almost all infections had been acquired by way of “shut contact, not airborne transmission.”

The replace introduced the company in keeping with proof of the hazard from airborne droplets that epidemiologists had famous because the pandemic unfolded final 12 months, and, in line with some specialists, additionally underscored the urgency for the federal Occupational Security and Well being Administration to challenge requirements for employers to handle potential airborne hazards within the office.

Dr. Fauci’s feedback on Sunday got here in response to a query about feedback that Dr. Scott Gottlieb, the previous head of the Meals and Drug Administration, made final week on CNBC. He mentioned that stress-free indoor masks mandates now — “particularly in environments the place you already know you will have a excessive stage of vaccination”— would give public well being officers “the credibility to implement them” once more within the fall or winter if instances surge once more.

Dr. Fauci, requested by George Stephanopoulos on ABC’s Sunday program “This Week” whether or not he agreed, mentioned: “I feel so, and I feel you’re going to in all probability be seeing that as we go alongside, and as extra folks get vaccinated.”

“The C.D.C. will probably be, virtually in actual time, George, updating their suggestions and their tips,” Dr. Fauci continued. “However sure, we do want to start out being extra liberal as we get extra folks vaccinated.”

Over a 3rd of the U.S. inhabitants — greater than 112 million folks — is absolutely vaccinated and one other 40 million folks have obtained the primary dose of a two-dose protocol.

The C.D.C., which points nationwide steering on masking, says that even vaccinated folks should continue to wear masks in indoor public spaces, together with eating places when they’re not actively eating and drinking. In lots of locations throughout the nation, it’s clear that the steering isn’t being adopted.

In a separate interview on Sunday, on CNN’s “State of the Union,” Jeffrey Zients, Mr. Biden’s Covid response coordinator, was considerably extra circumspect than Dr. Fauci when requested about Dr. Gottlieb’s feedback.

“I feel everyone seems to be drained, and carrying a masks is — it may be a ache,” Mr. Zients mentioned. “However we’re getting there. And the sunshine on the finish of the tunnel is brighter and brighter. Let’s sustain our guard. Let’s comply with the C.D.C. steering. And the C.D.C. steering throughout time will permit vaccinated folks an increasing number of privileges to take off that masks.”

Mr. Zients additionally recommended that as a substitute of reaching herd immunity — the purpose when sufficient persons are proof against the virus that it will possibly not unfold by way of the inhabitants — the aim must be to realize some sense of normalcy by getting 70 p.c of Individuals immunized. President Biden has referred to as for 70 p.c to have at the least one dose by July 4.

Reaching 70 p.c will create “a sample of reducing instances, hospitalizations and deaths and take us right down to a sustainable low stage,” Mr. Zients mentioned, pointing to Israel, a world chief in vaccinations, as a mannequin.

In that nation, vaccinations have reached virtually 60 p.c of the inhabitants since they started on Dec. 19 final 12 months, and the seven-day common of recent instances has dropped from a excessive of greater than 8,600 on Jan. 17 to fewer than 60 as of Saturday.