Half of US states have fully vaccinated at least 50% of adults. The impact is starting to come into focus

At least 25 states, plus Washington, DC, have now fully vaccinated at least half of their adult residents, data published Sunday by the Centers for Disease Control and Prevention shows.

Those states are Alaska, California, Colorado, Connecticut, Delaware, Hawaii, Iowa, Maine, Maryland, Massachusetts, Michigan, Minnesota, Nebraska, New Hampshire, New Jersey, New Mexico, New York, Oregon, Pennsylvania, Rhode Island, South Dakota, Vermont, Virginia, Washington and Wisconsin.

Four of those states – Connecticut, Maine, Massachusetts and Vermont – have fully vaccinated more than half of their total resident population, not just adults, the CDC said Monday.

The impact of the vaccination program is obvious.

New York Mayor Bill de Blasio said Monday that the city’s public schools will fully return to in-person learning in September, with no remote option. Face masks will still be required in schools, NYC Schools Chancellor Meisha Porter said.

Close to 700 doses of the Moderna Covid-19 Vaccine will be given out today at Central Falls High School in Central Falls, Rhode Island, on February 13, 2021. - The city of Central Falls is currently offering Covid-19 vaccinations to any adult 18 years and older in contrast to the rest of the state which is following state guidelines and offering only to certain groups, frontline workers and people 75 years old and older. According to the US Census bureau, Central Falls is made up of over 66% Hispanic and almost 13% Black residents. "Everybody that lives or works here is a priority, if we don't fix the problem, where the problem is. We are just going to continue spreading this disease," said Mayor Maria Rivera. (Photo by Joseph Prezioso / AFP) (Photo by JOSEPH PREZIOSO/AFP via Getty Images)

Related article An 8th US state just reached a critical Covid-19 vaccination milestone

“We have proven that we can beat back Covid all over this country, and school opens four months from now,” de Blasio said on MSNBC’s “Morning Joe.” “So, I absolutely believe Covid will continue to go down, vaccinations will go up, recovery will be strong.”

In New Jersey, mask-wearing and social distancing requirements will be lifted Friday regardless of vaccination status, except for certain designated situations, Gov. Phil Murphy said Monday. Individual businesses can require employees and customers to wear masks if they choose, he said.

In Michigan, Gov. Gretchen Whitmer announced updated return-to-work protocols and guidance including allowing fully vaccinated employees to forgo wearing face masks and social distancing. Whitmer said the state has reached the 55% vaccination threshold.

Air travel hit a new high of the pandemic last weekend, with the Transportation Security Administration saying it screened 90% of the total number of people it screened on the equivalent day in 2019, long before the pandemic.

The Sunday figure of 1.86 million people screened is compared to nearly 2.1 million on the equivalent Sunday of 2019. At this point in 2020, the pandemic had driven air travel into a deep hole, and the TSA reported only 267,000 screenings.

The new number beat the previous record set one week earlier.

With Memorial Day just one week away, planes are nearly as full as before the pandemic. The average domestic flight is carrying 98 passengers, compared to an average of 99 passengers in 2019, according to data from Airlines for America.

Nearly half of all in the US have gotten one shot

Across the US, roughly 61.3% of American adults have received at least one Covid-19 vaccine dose and about 49.6% are fully vaccinated, CDC data shows.

More than 49% of the country’s total population has gotten at least one shot while more than 39% of the population is fully vaccinated, the data shows.

The state with the highest proportion of adults who have been fully vaccinated against Covid-19 is Maine – with more than 62% of people 18 and older having completed their shots.

The country is recording some of the lowest Covid-19 metrics in roughly a year and officials say it could soon get even better than that.

“Across the country, cases of Covid-19, serious illness and loss of life are all down dramatically,” White House senior Covid-19 adviser Andy Slavitt said in a briefing Friday. “And they can be brought down even further and the risk of a future wave in your community significantly reduced if we keep up the pace of vaccinations.”

Pharmacy technicians fill syringes with Pfizer's Covid-19 vaccine March 2 at the Portland Expo in Portland, Maine.

Here’s how many Covid-19 cases US is averaging

In the past week, the US has averaged more than 25,000 new cases and more than 540 new Covid-19 deaths daily, according to data from Johns Hopkins University.

Those are still high numbers, experts say.

But they’re way down from where the nation was just weeks ago. The country’s average of daily Covid-19 cases in the past week is down by 57% from what it was a month ago, according to Johns Hopkins data.

Young woman sitting in hospital waiting for a doctor's appointment. Patients In Doctors Waiting Room

Related article The women possibly at higher risk for Covid-19 that no one is talking about

And the seven-day average of daily Covid-19 deaths is down by 23% from a month ago, according to that data.

“The people who are getting infected now tend to be people who are younger, less vulnerable to the infection, because a lot of the vulnerable population has been vaccinated,” Dr. Scott Gottlieb, former Food and Drug Administration commissioner, said Sunday on CBS’ “Face the Nation.”

More than 85% of Americans 65 and older have received at least one Covid-19 shot and nearly 74% are fully vaccinated, CDC data shows.

“The people most likely to get into trouble with Covid have now been protected through vaccination and you’re seeing a rapidly declining rate of new hospitalizations as a consequence of that fact,” Gottlieb added.

Burnout in the health care industry

Most health care workers in the United States are experiencing burnout after battling the coronavirus pandemic, US Surgeon General Dr. Vivek Murthy said Monday.

“What worries me is that the burnout rate among clinicians right now is extraordinarily high. It’s well past 50%,” Murthy said in an event hosted by the Department of Health and Human Services’ Covid-19 Community Corps.

“The majority of health care workers in our country are saying that they are experiencing burnout at the prospect of even continuing clinical work after this pandemic is over,” Murthy said.

The nation could be in danger of losing doctors from an already shrinking workforce, he said.

“We had a shortage of health care workers before this pandemic began, and my worry is that we will be worse off unless we find a way to make clinician well-being a national priority,” he said.

“We need to support our health care workers and understand that yes, they are still individuals who know how to help save lives, but first and foremost they are human beings who are going through an extraordinarily hard time,” Murthy added.

Children don’t need masks outdoors, expert says

Gottlieb also doesn’t think children need to be wearing face masks outside anymore and the CDC will have to revise its guidance on summer camps, he said Sunday.

In late April, the agency said that in summer camps, people who can get vaccinated against Covid-19 should do so but everyone should wear masks, distancing will still be necessary and staying outdoors is best.

Related article What the new CDC mask guidance means for kids under 12

“Wearing a mask, you know, is difficult in the summertime when it’s hot, and I don’t think that the risk merits that,” Gottlieb said. “But I do think parents need to make an assessment about the risk of the environment that the child is going to be in.”

For example, in crowded indoor settings, having kids wear masks is reasonable, he said.

The CDC has said it’s working on updating its summer camp guidance.

Since there is no vaccine for children younger than 12, the American Academy of Pediatrics (AAP) said last week that children and adults who are not yet fully vaccinated against Covid-19 still need to wear masks in certain settings.

Aiden Arthurs receives the Pfizer-BioNTech Covid-19 Vaccine from Pharmacist Andrew Mac (R) at the Jewish Federation/JARC's offices in Bloomfield Hills, Michigan, on May 13, 2021. - The US Food and Drug Administration (FDA) on May 10, 2021 authorized the use of the Pfizer-BioNTech Covid-19 vaccine for children aged 12 to 15 years old. (Photo by JEFF KOWALSKY / AFP) (Photo by JEFF KOWALSKY/AFP via Getty Images)

Related article Are you a parent who's hesitant about getting the Covid-19 vaccine for your child? Share your story.

Children should continue wearing masks in public places as they have throughout the pandemic, particularly when social distancing isn’t possible, said Dr. Yvonne Maldonado, chair of the AAP’s Committee on Infectious Diseases.

Children can take off their masks when they are with family members from the same household or at small gatherings with fully vaccinated family members and friends and during water sports, such as swimming, or activities in which masks could pose a safety risk, such as gymnastics.

Children younger than 2 also do not need to wear masks, Maldonado said.

CNN’s Greg Thomas, Taylor Romine, Naomi Thomas, Michael Nedelman and Ben Tinker contributed to this report.