President Biden on Monday referred to as on governors and mayors to maintain or reinstate mask-wearing orders, saying that due to “reckless conduct,” the coronavirus was once more spreading quick, threatening the progress the nation has made to this point in opposition to the pandemic.

“Persons are letting up on precautions, which is a really dangerous factor,” he stated. “We’re giving up hard-fought, hard-won positive factors.”

Mr. Biden requested the nation to persevere, saying that he had directed his coronavirus staff to make sure that there was a vaccination web site inside 5 miles of 90 % of People inside three weeks.

He stated doses at the moment are plentiful sufficient that 9 of ten adults within the nation — or extra — can be eligible for a shot by April 19. Beforehand, he had solely referred to as on states to broaden eligibility to all adults by Could 1.

Whereas it should take time for everybody to get an appointment, Mr. Biden stated, “you gained’t have to attend until Could to be eligible on your shot.”

Buoyed by guarantees of larger shipments of doses in coming weeks, many states have already moved shortly to permit extra folks to enroll in photographs. On Monday, New York said all adults would be eligible starting April 6, becoming a member of at the least 37 different states that may make all grownup residents eligible for vaccinations by mid-April.

Requested if states ought to pause their reopening efforts, the president replied merely, “Sure.” He stated that governors, mayors, native officers and companies ought to demand mask-wearing, calling it a “patriotic responsibility” that’s essential to the nation’s struggle in opposition to the virus.

“Please, that is politics,” he stated. “Reinstate the mandate should you let it down.”

Mr. Biden spoke a number of hours after Dr. Rochelle Walensky, director of the Facilities for Illness Management and Prevention, issued maybe her most impassioned warning thus far a couple of doable fourth surge of the coronavirus, saying she felt a recurring sense of “impending doom.”

The nation has “a lot motive for hope,” she stated, her voice trembling with emotion. “However proper now I’m scared.”

“I’m asking you to only maintain on a bit of longer, to get vaccinated when you’ll be able to, so that every one of these those who all of us love will nonetheless be right here when this pandemic ends,” she stated at a White Home briefing.

According to a New York Times database, the seven-day common of recent virus instances as of Sunday was about 63,000, a stage akin to late October, and up from 54,000 a day two weeks earlier, a rise of greater than 16 %. Comparable upticks up to now over the summer time and winter led to main surges within the unfold of illness, Dr. Walensky stated. Nonetheless, new instances and deaths have declined from the early January peak, although the seven-day common of recent deaths stays close to 1,000 a day.

The wave of recent instances comes as the nation rapidly broadens eligibility for vaccines, the typical variety of day by day photographs continues to rise, and a new C.D.C. report released Monday confirmed the findings of last year’s clinical trials that vaccines developed by Moderna and Pfizer are extremely efficient in opposition to Covid-19 illness. The report documented that the vaccines work to stop symptomatic and asymptomatic infections underneath real-world circumstances.

The seven-day common of vaccines administered hit 2.7 million on Sunday, a slight enhance over the tempo the earlier week, in keeping with information reported by the C.D.C. However worrisome sizzling spots proceed popping up.

In 9 states over the previous two weeks, virus instances have risen greater than 40 %, the Occasions database exhibits. Michigan led the way in which with a 133 % enhance. The Northeast has additionally seen a troubling rise in virus instances. Connecticut reported a 62 % soar in instances over the previous two weeks, and New York and Pennsylvania each reported will increase of greater than 40 %.

Michigan’s spike has not been traced to anyone occasion, however epidemiologists have famous that instances began to leap after the state eased restrictions for indoor eating on Feb. 1 and lifted different restrictions in January. Different sizzling spots included North Dakota, the place instances rose by practically 60 % and Minnesota, the place instances have jumped 47 %. Of these states, North Dakota is the one one and not using a present masks mandate.

Dr. Walensky on Monday described “a sense of nausea” she would expertise final 12 months when, as a health care provider at a Boston hospital, she noticed the corpses of Covid-19 sufferers piled up, overflowing from the morgue; and when she stood, “gowned and shielded,” because the final one in a affected person’s room earlier than they died alone, with out household.

On the time, she stated, there have been so many unknowns concerning the virus. However now, with the vaccination program quickly gaining pace, she stated, she is hopeful the pandemic might be beat.

Dr. Walensky, who has issued a number of warnings in latest weeks about the necessity to sustain mask-wearing and social distancing, stated she deliberate to speak to governors concerning the dangers of prematurely lifting restrictions on Tuesday throughout a weekly name concerning the pandemic and vaccine rollout.