Valencia Street in San Francisco in March. San Francisco General Hospital announced this past week that it had no Covid-19 patients for the first time since March 5 of last year.
Jim Wilson/The New York Times

The United States is adding fewer than 30,000 cases a day for the first time since June of last year, and deaths are as low as they’ve been since last summer. In much of the country, the virus outlook is improving.

Nearly 50 percent of Americans have received at least one vaccine shot, and though the pace has slowed, the share is still growing by about two percentage points per week.

“I think by June, we’re probably going to be at one infection per a hundred thousand people per day, which is a very low level,” Dr. Scott Gottlieb, former head of the Food and Drug Administration, said Sunday on the CBS program “Face the Nation.” The U.S. rate is now 8 cases per 100,000, down from 22 during the most recent peak, when new cases averaged about 71,000 on April 14.

The share of coronavirus tests coming back positive has fallen to below 3 percent for the first time since widespread testing began, and the number of hospitalized patients has fallen to the lowest point in 11 months, Dr. Eric Topol of the Scripps Research Translational Institute noted this week. For the first time since March 5 of last year, San Francisco General Hospital had no Covid-19 patients — “a truly momentous day,” Dr. Vivek Jain, an infectious disease physician at the hospital, said on Thursday.

Michigan, the state that reported one of the largest surges in the spring, has rapidly improved. About 1,400 cases were identified on Sunday, compared with about 7,800 cases a day in mid-April.

The virus remains dangerous in communities with low vaccination rates, and getting vaccines into these communities is crucial in continuing to curb the virus. As the virus continues to mutate, vaccines may need to be updated or boosters may need to be added.

The United States is reporting about 25,700 coronavirus cases daily, a 39 percent decrease from two weeks ago. Deaths are down 14 percent over the same period, to an average of 578 per day.

Since the Centers for Disease Control and Prevention issued guidance that said vaccinated people could forgo masks in most situations indoors and outside, states have followed suit.

Because of changing mask rules and guidance, people will need to rely on their own judgment in some circumstances, Dr. Gottlieb said Sunday. “We’re going to have to protect ourselves based on our own assessment of our risk and our own comfort,” he said.

For instance, he said, people who are unvaccinated or in an area where infections are still high will be at higher risk than others.

“So I think people may need to make individual assessments,” he said, adding that while unvaccinated children in crowded indoor situations might need to keep masks on, “I don’t think kids need to be wearing masks outside anymore.”

Although experts who spoke with The New York Times said they were optimistic, they cautioned that the virus won’t be eradicated in the United States but would likely instead become a manageable threat we learn to live with, like influenza.

Until then, Stacia Wyman, a senior genomics scientist at the University of California, Berkley, said Americans should remain concerned as long as the virus continues to spread and evolve in parts of the world that lack vaccines.

“I think that the world will be struggling with this,” she said. “As long as that is happening, the U.S. will be struggling with it as well.”

James Gorman contributed reporting.

A lone person getting vaccinated in April in Elizabethton, Tenn., at a center that can accommodate 300 people a day. Several southern states are lagging in vaccinations.
Erin Schaff/The New York Times

Almost half of Americans have received at least one dose of a Covid-19 vaccine. But the U.S. vaccination story varies widely across regions, with New England surging ahead of the national average and much of the South lagging far behind.

In five of the six New England states, more than 60 percent of residents are at least partly vaccinated, according to data from the Centers for Disease Control and Prevention. It’s a different story in the South, where Mississippi, Alabama, Arkansas, Georgia, Louisiana and Tennessee have the country’s lowest rates of residents who have received at least one shot. The rates in those states are all below 40 percent, with Mississippi, at 33 percent, at the bottom of the list.

The White House and state governments, after relying on mass vaccination sites for months, are turning their focus to more targeted, smaller-scale efforts to vaccinate underserved, harder-to-reach communities.

“This next phase of the vaccination campaign was — will be driven, more than anything, by the people and organizations and communities who help to vaccinate their families, their friends and others in their neighborhoods,” Dr. Vivek Murthy, the surgeon general, said on Friday during a White House news conference. “It’s why we’ve been saying that addressing access, motivation and vaccine confidence requires an all-hands-on-deck approach.”

That strategy has been employed by Dr. John B. Waits, the chief executive of Cahaba Medical Care, which has 17 clinics in underserved communities in Alabama.

“Conversations with people you trust have always been important to us,” he said on Friday. “I’ve been on Facebook Live. I say: ‘Ask us the hard questions. Let’s talk.’ We pivot to the individual exam room, where they trust me to answer. We’re having success with that approach, but it’s not at the speed that the pandemic needs.”

The low rate in the South worries Thomas A. LaVeist, an expert on health equity and dean of the School of Public Health and Tropical Medicine at Tulane University in New Orleans.

“You have the carrot and stick,” he said. “I’m beginning to think that the stick is the more likely scenario.”

Dr. LaVeist said the incentive that would work fastest for adults would be mandates by employers, who are uniquely positioned to require large numbers of Americans who otherwise would not receive a vaccination to do so because their employment depends on it. The federal government has issued guidance that says employers can require workers to get a Covid-19 vaccine and bar them from the workplace if they refuse.

Dr. Murthy cited a Kaiser Family Foundation survey that found 28 percent of those who were employed said they would be more likely to get vaccinated if they were given time off to receive and recover from the vaccine. Another 20 percent said they would be more likely to get vaccinated if their shot was administered at their workplace. The survey looked at those who are unvaccinated but wanted to get a vaccine as soon as possible.

Dr. LaVeist and other experts, however, say the biggest hurdle among the vaccine hesitant is anxiety over possible side effects. “How was it possible to deploy the vaccine so quickly? If more people understand that, then more people will take the vaccine,” Dr. LaVeist said. “Corners were not cut.”

A recent New York Times report from Greene County, a rural area in northeastern Tennessee, revealed the most common reason for vaccine apprehension was fear that the vaccine was developed in haste and that long-term side effects were unknown. These decisions are also entangled in a web of views about autonomy, science and authority, as well as a powerful regional and somewhat romanticized self-image: We don’t like outsiders messing in our business.

Vaccine hesitancy in any U.S. region poses a threat to all Americans, experts warn, because the longer it takes to vaccinate people, the more time that the virus has to spread, mutate and possibly gain the ability to evade vaccines.

“My big concern is that there is going to be a variant that’s going to outsmart the vaccine,” Dr. LaVeist said. “Then we’ll have a new problem. We’ll have to revaccinate.”

People wearing and not wearing masks in San Antonio, Texas, this month.
Christopher Lee for The New York Times

With vaccination spreading across the United States, social life has begun to bend toward a semblance of normalcy: dinner parties, restaurants, spontaneous encounters with strangers, friends and colleagues on the street or in the office. It’s exciting but also slightly nerve-racking.

“I think there will be a period of heightened anxiety as we meet people face-to-face again,” Adam Mastroianni, a fifth-year Ph.D. student in psychology at Harvard, told me (over the phone).

I’d called Mr. Mastroianni for some help in rediscovering this ancient calculus. In March, he and his colleagues published a paper — “Do conversations end when people want them to?” — on one of the stickier aspects of human interaction.

How do you begin to quantify this?

For our paper, we ran two main studies. In the first, we asked a big sample of people to recall the last conversation they’d had and to tell us about it: Was there any point in that conversation when they felt ready for it to end? When was that? Or if the conversation ended sooner than desired, how much longer did they want it to go? In our second study, we brought people into the lab and had them talk to somebody new. Afterward, we asked both people the same questions, had them guess what they thought the other person wanted and compared their responses.

A few things were really consistent. One was that most people reported that the conversation didn’t end when they felt ready for it to end; about two-thirds would have preferred it to end sooner. In fact, only 17 percent of people felt the conversation ended when they wanted it to. And those people rarely overlapped; in only 2 percent of conversations were both people satisfied with when it ended.

Why was that?

Two reasons. The first is that people don’t want to talk for the same amount of time; we can’t both get what we want if we want different things. The second problem is that people didn’t know what the other person wanted.

That sounds a lot like where we are with mask-wearing these days. I’m vaccinated, and highly unlikely to catch or spread the coronavirus. Yet I still wear a mask, even outdoors sometimes — why?

If I’m running past someone who is wearing a mask, out of politeness to them I’m going to put my mask up. It’s obviously ridiculous. But the fact that they’re wearing a mask suggests to me that they feel that it’s the right thing to do. And I don’t want to signal to that person that I don’t care about their choice or that I think their choice is bad. There’s something that seems kind of confrontational about even passing somebody on the sidewalk who’s wearing a mask when you’re not, and I don’t want to have that confrontation.

What have you learned personally from your years of studying conversation?

That I should be spending way less time trying to play fourth-dimensional chess in my mind during my conversations, and just try to pay more attention and let them unfold naturally — and take solace in the fact that people really enjoy these conversations, a lot more than they expected to.

A vaccination center in Karachi, Pakistan, this month. Critics say private sales in Pakistan and around the world make inoculations available only to the wealthy.
Asif Hassan/Agence France-Presse — Getty Images

In Pakistan, an inoculation push is making doses available to those who can pay for them. But most Pakistanis can’t afford them, and even those who can are being stymied by tight global supplies.

Access to coronavirus vaccines has thrown a stark light on global inequality. The United States and other rich countries have bought up most of the world’s vaccine supplies to protect their own people, leaving millions of doses stockpiled and in some places unused. Less developed countries are scrambling over what’s left, with some — like Pakistan — turning to private sales.

“The Pakistani example is a microcosm of what has gone wrong with the global response — where wealth alone has primarily shaped who gets access,” Zain Rizvi, an expert on medicine access at Public Citizen, a Washington, D.C., advocacy group, said in an email. “Ending the pandemic will require the global community to do much more than just that.”

Pakistan says the private program could make more free shots available to low-income people. By purchasing doses of the Russian-made Sputnik 5 vaccine, the country’s wealthy wouldn’t need to get the free doses, which are made by Sinopharm of China.

The need for vaccines in Pakistan is growing. The country of nearly 220 million people is reporting more than 2,500 new infections a day, but its low rate of testing suggests many more cases remain undetected.

For those who can afford the doses, frustration is growing. Junaid Jahangir, an Islamabad-based lawyer, said several of his friends got private inoculations. He registered with a private lab for Sputnik V but got a text message later saying that the vaccination drive was on hold.

“I am being denied a fair chance to fight this virus if I end up getting infected,” he said.

Waiting to be vaccinated in San Antonio this month. Some coronavirus patients and their families have been left mired in debt despite rules meant to protect them from exorbitant health care costs.
Tamir Kalifa for The New York Times

Americans with serious illnesses regularly face exorbitant and confusing bills after treatment, but things were supposed to be different for coronavirus patients.

Many large health plans wrote special rules, waiving co-payments and deductibles for coronavirus hospitalizations. When doctors and hospitals accepted bailout funds, Congress barred them from “balance billing” patients — the practice of seeking additional payment beyond what the insurer has paid.

Interviews with more than a dozen patients suggest those efforts have fallen short.

For 10 months, The New York Times has tracked the high costs of coronavirus testing and treatment through a crowdsourced database that includes more than 800 medical bills submitted by readers.

Those bills show that some hospitals are not complying with the ban on balance billing. Some are incorrectly coding visits, meaning the special coronavirus protections that insurers put in place are not applied. Others are going after debts of patients who died from the virus, pursuing estates that would otherwise go to family members.

The United States is estimated to have spent over $30 billion on coronavirus hospitalizations since the pandemic began, according to Chris Sloan, a principal at the health research firm Avalere. The average cost of each hospital stay is $23,489. Little research has been published on how much of that cost is billed to patients.

Some patients are postponing additional medical care for long-term side effects until they can resolve their existing debts. They are finding that long-haul coronavirus often requires visits to multiple specialists and many scans to resolve lingering symptoms, but they worry about piling up more debt.

A young woman receiving her Pfizer-BioNtech vaccine in Louisville, Ky., this month.
Jon Cherry for The New York Times

The Centers for Disease Control and Prevention is looking into reports that a very small number of teenagers and young adults vaccinated against the coronavirus may have experienced heart problems, according to the agency’s vaccine safety group.

The group’s statement was sparse in details, saying only that there were “relatively few” cases and that they may be entirely unrelated to vaccination. The condition, called myocarditis, is an inflammation of the heart muscle, and can occur following certain infections.

The C.D.C.’s review of the reports is in the early stages, and the agency has yet to determine whether there is any evidence that the vaccines caused the heart condition. The agency has posted guidance on its website urging doctors and clinicians to be alert to unusual heart symptoms among young people who had just received their shots.

“It may simply be a coincidence that some people are developing myocarditis after vaccination,” said Dr. Celine Gounder, an infectious disease specialist at Bellevue Hospital Center in New York. “It’s more likely for something like that to happen by chance, because so many people are getting vaccinated right now.”

The cases seem to have occurred predominantly in adolescents and young adults about four days after their second dose of one of the mRNA vaccines, made by Moderna and Pfizer-BioNTech. And the cases were more common in males than in females.

“Most cases appear to be mild, and follow-up of cases is ongoing,” the vaccine safety group said. The C.D.C. strongly recommends Covid vaccines for Americans ages 12 and older.

Police officers checking the credentials of commuters during a lockdown imposed to curb the spread of the coronavirus in the Indian state of Kerala this month.
R S Iyer/Associated Press

As a second virus wave has crushed India, officials in the southern state of Kerala have stepped in where the central government under Prime Minister Narendra Modi has failed, in many ways, to provide relief for victims of the world’s worst coronavirus outbreak.

An ad hoc system of local officials, online networks, charities and volunteers has emerged in India to fill the gaps left by the stumbling response of the central government and many states. Patients around India have died for lack of oxygen in hospitals where beds filled up quickly.

Kerala has adapted by closely tracking patients and supplies with a network of health care workers and coronavirus “war rooms.” Though supplies have tightened, the state’s hospitals enjoy access to oxygen, with officials having expanded production months ago. Doctors there talk patients through their illness while they’re at home. Kerala’s leaders work closely with on-the-ground health care workers to watch local cases and deliver medicine.

Kerala is by no means out of trouble. Deaths are rising. Workers face long hours and tough conditions. The situation could still worsen as the outbreak spreads from cities into rural areas.

In addition to its coordination centers, Kerala has won praise for how it has tracked virus variants. Scientists are studying whether a variant first found in India has worsened the country’s outbreak, though they have been hindered by a lack of data. Kerala has used gene sequencing since November to track variants, helping to drive policy decisions, said Dr. Vinod Scaria, a scientist at the CSIR Institute of Genomics and Integrative Biology in New Delhi.

“It’s the only state that has not given up at any point in time,” Dr. Scaria said.