Covid-19 vaccines being prepared near Paris in April.
Credit…Dmitry Kostyukov for The New York Times

As the Delta variant rages around the world, a heated debate has arisen over whether public health officials should recommend booster shots.

On one side are global health officials who contend that available vaccines would be better used to inoculate high-risk people in poor nations where few have gotten the shots.

On the other are leaders and health officials in wealthier countries, who are setting aside doses for more vulnerable people who may need additional doses to protect them from the virus.

Biden administration officials have already begun developing a plan that would roll out third shots of the Pfizer and Moderna vaccines as early as this fall, saying the logistics are too complicated to wait for scientific certainty that the extra doses are really needed.

Full vaccination is highly effective at protecting against severe disease caused by the virus, and it is not yet clear how soon additional doses might be necessary for certain groups. Some vaccines require boosters to remain highly protective.

In the United States, federal officials last week authorized a third shot of the Pfizer and Moderna vaccines for people with compromised immune systems because of organ transplants, chemotherapy or other medical conditions.

But officials at the Food and Drug Administration and the Centers for Disease Control and Prevention have said that authorizing third doses for immunocompromised people was a separate issue from whether booster doses were needed for the rest of the population.

Pfizer has pushed for swift authorization of third doses, but U.S. officials said in July that they would need more data, possibly months’ worth, before they could answer the question.

Some individuals are taking matters into their own hands. Just over a million people who received a two-dose vaccine in the United States have already received a third dose, Dr. Kathleen Dooling, a C.D.C. official, said on Friday. It was not clear how many were immunosuppressed.

Some nations, including France, Germany and Israel, have authorized booster shots for older people. Israel said on Friday that it was lowering the age of eligibility for a third dose to 50.

Officials from the World Health Organization argue fiercely that booster programs will further deprive lower-income countries of desperately needed vaccines.

Leaving large swaths of the world unvaccinated, W.H.O. officials say, is wasteful, shortsighted and gives the virus enormous latitude to mutate into potentially more transmissible or virulent variants.

International vaccine distribution has been wildly unequal. Many countries in North America and Europe have at least partially vaccinated more than half of their populations, compared with barely more than 4 percent of Africa’s population, according to the Our World in Data project at Oxford University.

At a briefing this month, the W.H.O.’s director general, Dr. Tedros Adhanom Ghebreyesus, called for richer countries to stop giving third doses until the end of September. “We cannot — and we should not — accept countries that have already used most of the global supply of vaccines using even more of it, while the world’s most vulnerable people remain unprotected,” he said.

In an essay in the British newspaper The Guardian on Friday, Andrew Pollard, the director of the Oxford Vaccine Group at the University of Oxford, and Seth Berkley, the chief executive of Gavi, a global vaccine alliance, said that there was not enough evidence yet to enable a decision on boosters.

“Large-scale boosting in one rich country would send a signal around the world that boosters are needed everywhere,” they wrote. “This will suck many vaccine doses out of the system, and many more people will die because they never even had a chance to get a single dose.”

Prime Minister Muhyiddin Yassin of Malaysia in Kuala Lumpur, the capital, on Monday. He will continue as interim premier until a successor is appointed.
Credit…FL Wong/Associated Press

Battered by public anger over the Malaysian government’s handling of the coronavirus and acknowledging he had lost the support of lawmakers, Prime Minister Muhyiddin Yassin and his entire cabinet resigned on Monday, signaling an end to a tumultuous 17-month reign.

For now, Mr. Muhyiddin will continue to steer the Southeast Asian country through its worst wave of the virus yet, as he will stay on as interim premier until a successor is appointed. The king said that the country would not hold an election during the pandemic, leaving him to appoint the next leader, according to Reuters.

The resignations plunged Malaysia even deeper into political turmoil while it contends with one of the world’s worst surges of the virus. The nation of about 32 million people has averaged more than 20,000 cases per day in the last 14 days, and just 33 percent of the population is fully vaccinated, according to a New York Times database. The total death toll from the pandemic in the country is at least 12,510.

Mr. Muhyiddin pledged in a nationally televised address that the entire population would be vaccinated by the end of October, according to The Straits Times.

He also said that he accepted he had lost political support. “I will not conspire with kleptocrats, or interfere with the judiciary or turn my back on the Constitution to stay in power,” he said.

Mr. Muhyiddin assumed power in March 2020 when Mahathir Mohamad, 94, was ousted two years after he had been voted in as prime minister. A veteran nationalist politician, Mr. Muhyiddin was aligned with a scandal-tainted governing coalition that had dominated the country for more than 60 years before Mr. Mahathir’s election success.

Taking over with a thin majority as the coronavirus crisis began to roar, Mr. Muhyiddin used the pandemic to limit the ability of opponents to organize and challenge his power. But calls for his resignation gathered force as the country issued multiple lockdown orders, botched its vaccine rollout and endured widespread hunger.

The Metropolitan Museum of Art last month.
Credit…George Etheredge for The New York Times

New York City plans to require visitors to its museums and other cultural institutions to be vaccinated, a city official said Monday.

The policy — which Mayor Bill de Blasio was expected to outline at a news conference on Monday that also addressed sports activities — will require that visitors and employees at the city’s museums, concert halls, aquariums and zoos be vaccinated, according to a City Hall official who was granted anonymity because the policy had yet to be officially announced.

Children younger than age 12, who are not eligible to be vaccinated, will have to be accompanied by a vaccinated person and will be encouraged to wear masks.

The city plans to conduct a $10 million media campaign to inform the public of the new requirements, according to the City Hall official.

The 33 museums and arts groups operating in city-owned buildings or on city-owned land — known as members of the Cultural Institutions Group — had been in discussions over the last few weeks with the city’s Department of Cultural Affairs.

There was broad consensus among those arts organizations — as well as others that are not city-owned — in favor of a vaccination mandate.

“Everyone wants their audiences and their employees to be safe,” said Lucy Sexton, the executive director of New Yorkers for Culture & Arts, an advocacy group. Ms. Sexton — together with Taryn Sacramone, the executive director of the Queens Theater — last year started a daily Zoom call with more than 200 arts leaders to pool support and information during the coronavirus pandemic.

Proof of vaccination can include a photo or hard copy of an official vaccination card, New York City vaccination apps or an official vaccine record for cleared vaccines.

Earlier this month, Mr. de Blasio announced that at least one vaccination would be required for indoor concerts — as well as for indoor gyms and indoor dining — becoming the first U.S. city to issue such a mandate.

Students wearing school-required masks at Lamar Elementary School in San Antonio on Thursday.
Credit…Matthew Busch for The New York Times

The Texas governor can ban mask mandates, at least for now, after the State Supreme Court on Sunday granted the state’s request for an emergency stay of an appellate court ruling that would have allowed mandatory face coverings in schools.

The decision is temporary because the State Supreme Court, whose justices are elected and are currently all Republicans, must make a final ruling.

Late on Friday, after Gov. Greg Abbott’s ban suffered at least three legal setbacks, the state’s attorney general, Ken Paxton, said he was asking the State Supreme Court to consider Mr. Abbott’s policies.

The escalating battle comes as schools around the country open or prepare to, with tens of millions of children under 12 ineligible for vaccination, and as hospitalizations of young people have been increasing amid the spread of the highly transmissible Delta variant.

Some Republicans have cast mask rules as an infringement on parental rights, while many Democrats hold that they are a matter of public health.

The setbacks for Mr. Abbott on Friday were in areas with Democratic leaders, rampant coronavirus cases and rising hospitalizations.

Vaccinations in Texas lag behind those of many other states, and deaths are also rising, though far more slowly than in prior waves, given that the majority of the oldest and most vulnerable residents are now vaccinated.

A state district judge gave Harris County, which includes Houston, and several school districts across the state temporary permission to implement safety measures, including mask mandates.

In San Antonio, the state’s Fourth Court of Appeals denied Mr. Abbott’s challenge to an earlier ruling upholding a school mask mandate for Bexar County.

Shortly after the San Antonio court issued its ruling, the Fifth Court of Appeals in Dallas denied Mr. Abbott’s challenge to a county official’s mask mandate for public schools, universities and businesses.

The official who issued that order, Clay Jenkins, praised the ruling. “We should all be together; Team Human v Virus,” he wrote on Twitter. “I’ll keep following the doctor’s advise and work with anyone to beat #COVID19.”

On Sunday evening, after the State Supreme Court’s decision, Judge Jenkins wrote on Twitter that the court had “narrowly ruled.” “We won’t stop working with parents, doctors, schools,” he continued, “to protect you and intend to win that hearing.”

Getting vaccinated in San Francisco this month. The symptoms of long Covid — severe fatigue, brain fog, headache, muscle pain and sleep problems — can persist for weeks or months after an active infection has ended.
Credit…Mike Kai Chen for The New York Times

While some breakthrough cases among those who are vaccinated against Covid-19 are inevitable, they are unlikely to result in hospitalization or death. But one important question about breakthrough infections remains: Can the vaccinated develop so-called long Covid?

Long Covid refers to a set of symptoms — such as severe fatigue, brain fog, headache, muscle pain and sleep problems — that can persist for weeks or months after the active infection has ended. The syndrome is poorly understood, but studies suggest that 10 to 30 percent of adults who catch the virus may experience long Covid.

Most data collected about long Covid has been in the unvaccinated population.

While preliminary research suggests that it is possible for a breakthrough case to lead to symptoms that can persist for weeks to months, there are still more questions than answers.

“I just don’t think there is enough data,” said Dr. Zijian Chen, medical director at the Center for Post-Covid Care at Mount Sinai Health System in New York. “It’s too early to tell. The population of people getting sick post vaccination isn’t that high right now, and there’s no good tracking mechanism for these patients.”

One recent study of Israeli health care workers published in The New England Journal of Medicine offers a glimpse of the risk of long Covid after a breakthrough infection. Among 1,497 vaccinated health care workers, 39 of them — about 2.6 percent — developed breakthrough infections. (All of the workers were believed to have become infected after contact with an unvaccinated person, and the study was conducted before the Delta variant became dominant.)

While most of the breakthrough cases were mild or asymptomatic, seven out of 36 workers tracked at six weeks (19 percent) still had persistent symptoms.

But the study’s authors caution against drawing too many conclusions. The sample size — just seven patients — is small. And the research was designed to study antibody levels in the infected; it was not designed to study the risk of long Covid after a breakthrough infection.

Global Roundup

Waiting for vaccinations in Sydney, Australia, on Monday. The national government’s inoculation efforts have been widely criticized.
Credit…David Gray/Agence France-Presse — Getty Images

As the Delta variant of the coronavirus spreads beyond Sydney into the surrounding state of New South Wales, concern is mounting about the potential impact on vulnerable, unvaccinated Aboriginal Australians.

The Australian government had made Aboriginal people a priority group for vaccination because of the lack of health care services in the remote areas where many of them live. But as of Sunday, only 15 percent of Indigenous Australians over the age of 16 had been fully inoculated, compared with 26 percent of people in all of Australia.

The low rates among Aboriginal Australians are particularly concerning in the western part of New South Wales, which went into a lockdown on Saturday. Most of the area’s 98 coronavirus cases are among Indigenous people, Scott McLachlan, chief executive of the region’s health services, told the Australian Broadcasting Corporation.

Four of the cases have been found in the town of Walgett, where nearly half of the 6,000 residents are Aboriginal. There is a high prevalence of chronic health conditions among that population, and officials and Indigenous leaders fear that a wider outbreak could overwhelm local health care.

The Dharriwaa Elders Group, an association of Aboriginal elders in Walgett, said in a statement: “Many of our elders and others in Walgett experience health and social issues that make them vulnerable to contracting Covid-19. The impact on our community could be devastating.”

Ken Wyatt, the minister for Indigenous Australians, said that some were hesitant to get vaccinated because of news reports about the rare chance of blood clots associated with the AstraZeneca vaccine.

Prime Minister Scott Morrison last week defended the government’s slow vaccination efforts, which have been widely criticized.

“Australia is a very big country, and our Indigenous populations live in some of the remotest parts of our country,” he said on Friday. “It was always going to be the most challenging element of all the vaccine rollout.”

Dr. Kalinda Griffiths, a Yawuru woman and epidemiologist at the University of New South Wales, said the government had not been publishing information about how many Indigenous Australians had been vaccinated, making it difficult for communities to identify weak spots until an outbreak occurred.

“Now we’re on the back foot,” she said.

Experts have called for the release of region- and age-specific vaccination data for Indigenous communities.

Tighter virus restrictions were introduced on Monday in several parts of Australia. In New South Wales, it was the worst day of the pandemic so far. The state reported seven coronavirus-related deaths and 478 new cases. Hundreds of soldiers patrolled the streets of Sydney, which is in its eighth week of lockdown, to help enforce stay-at-home orders.

The state of Victoria, which includes Melbourne, tightened its lockdown restrictions, imposing a curfew of 9 p.m. to 5 a.m. and closing outdoor playgrounds. The Northern Territory, whose capital is Darwin, went into a snap 72-hour lockdown after the discovery of a single asymptomatic infection.

In other news around the world:

  • Hong Kong will add 15 more countries, including the United States, France and Spain, to its list of high-risk countries, meaning even vaccinated Hong Kong residents can return and face will face a 21-day hotel quarantine. It also upgraded Australia to medium-risk from low-risk. The changes, which take effect from midnight on Aug. 20, were to guard against the Delta variant, the government said in a statement on Monday.

  • Germany’s independent standing commission on vaccination recommends children between 12 and 17 be immunized against the coronavirus, it said in a statement on Monday, giving parents a long-awaited medical judgment in favor of vaccinating their teens just as schools reopen. Shortly after Pfizer-BioNTech and Moderna were approved for children 12 and older, the same commission recommended in June that only medically at-risk children should get the jab, saying it was not yet clear that the benefits outweighed the risk. The commission has now cited new data coming from the United States, where children 12 to 15 began getting vaccinated in mid-May after becoming eligible, as a factor in its latest recommendation. According to authorities, 24.3 percent of children between the ages of 12 to 17 in Germany have already received at least one jab.

As a new wave of the coronavirus surges in Kenya, the authorities have indefinitely extended a nightly curfew. People walked home along a highway on the outskirts of Nairobi, the capital.
Credit…Monicah Mwangi/Reuters

NAIROBI, Kenya — Scrutiny of police enforcement of coronavirus rules in Kenya has gained urgency after the deaths in custody of two brothers who were detained on suspicion of breaking a curfew.

The deaths have set off a fresh national reckoning over police brutality, particularly in enforcing Covid rules, as a fourth wave of the pandemic hits the country.

The brothers — Benson Njiru Ndwiga, 22, and Emmanuel Marura Ndwiga, 19 — were last seen alive on Aug. 1 in the town of Kianjokoma, in Embu County, eastern Kenya, where they were detained for being outdoors after the 10 p.m. nationwide curfew. Relatives found their bodies at a local morgue three days later.

An autopsy found that the brothers had died of head and rib injuries. Officers said the two men had fallen from a moving police vehicle, but the family and the public have doubted that the injuries were consistent with the police account.

The deaths of the brothers, who were students, led to demonstrations in Embu County. One person was killed when anti-riot officers shot at protesters and a police vehicle was set on fire. The brothers’ funeral on Friday attracted giant crowds and prompted calls for accountability.

On Monday, the inspector general of the police, Hilary N. Mutyambai, said that the Independent Policing Oversight Authority, a watchdog organization, had completed investigations into the brothers’ deaths and forwarded the findings to the national prosecutor. “All the officers have been suspended with immediate effect to pave way for prosecution,” Mr. Mutyambai said on Twitter, without naming the officers suspected of misconduct in the case.

Fred Matiang’i, the interior minister, met with the brothers’ family and said that the government would “stop at nothing to ensure justice is served.”

Coronavirus cases are surging in Kenya, driven largely by the more contagious Delta variant. The East African nation is one of four countries on the continent undergoing a fourth wave of the pandemic, according to the Africa Centers for Disease Control and Prevention.

Kenya has confirmed more than 220,000 total cases and 4,340 deaths from the virus so far, according to a New York Times tracker. In the four weeks ended Aug. 8, new case reports were about 30 percent higher than in the preceding period, the Africa C.D.C. reported, while the number of deaths increased by 56 percent. As in many places in Africa, vaccination is slow. In Kenya, only about 746,000 people — about 1.4 percent of the population of 53 million —  are fully vaccinated, according to the Ministry of Health.

The authorities tightened restrictions last month, extending the daily 10 p.m.-to-4 a.m. curfew indefinitely, limiting funerals to 50 attendees, urging employers to allow staff to work from home, and banning all public gatherings.

With presidential and parliamentary elections scheduled for next year, though, politicians have defied the rules and continued to hold rallies and large meetings with mostly unmasked crowds, drawing criticism from civil and religious groups.

Human rights groups have accused Kenya’s security forces for years of carrying out killings, abductions and torture. They say that the police have become especially heavy-handed during the pandemic.

At least 834 people have been killed by the police or were reported missing since 2007 — 166 of them last year — according to Missing Voices, a group of organizations that document police killings. The Independent Medico-Legal Unit, a nongovernmental organization based in the Kenyan capital, Nairobi, has documented 26 deaths and 49 cases of maltreatment connected with Covid enforcement.

On March 27, 2020, when the curfew was first introduced, baton-wielding officers beat people and used tear gas on dozens of people waiting for a ferry in the coastal city of Mombasa. A few days later, a 13-year-old boy was shot dead in a Nairobi neighborhood as the police moved to enforce curfew restrictions. An officer was later charged in the killing. More recently, thousands of people, including some trying to get to hospitals, were stranded in traffic in the capital in April as officers blocked highways and told drivers to sleep in their cars to avoid violating the curfew.

The Police Reforms Working Group, an alliance of national and local organizations in Kenya that includes Amnesty International and Transparency International, called the police violence and coronavirus crisis a “twin pandemic.” The alliance has condemned the death of the Ndwiga brothers and urged security forces to uphold citizens’ rights.

“A breach of these rights is an abdication of duty and illegality we condemn in the strongest possible terms,” the alliance said.

Taipei, the capital of Taiwan, in June. There are fewer than 10 locally transmitted cases a day on the island, which has favored a less heavy-handed approach than in China.
Credit…Ann Wang/Reuters

The most popular YouTube shows in Taiwan are pop music videos, clips of video gamers and, in recent months, the health minister’s daily updates on the coronavirus.

The briefings by the health minister, Chen Shih-chung, in which he and other officials take questions from the public about the island’s latest virus efforts, have become a hit, with hundreds of thousands of people tuning in each afternoon. The local edition of GQ called him a “minister of steel.” He uses infographics and memes, including one of a Health Ministry worker’s dog, to convey news about cases in Taiwan and how members of the public can stay vigilant.

Taiwan, where there are fewer than 10 locally transmitted cases a day, has favored a less heavy-handed approach than in China, instead raising awareness through public health campaigns, like the daily briefing. Masks are required in public spaces, and people typically abide by social-distancing rules when they go hiking, running, or even to swimming pools.

Through most of the pandemic, Taiwan has thrived as a bubble of normalcy and has mostly avoided strict lockdowns by imposing rigorous contact tracing and quarantines for foreign visitors.

When it faced a surge of cases in May, rather than forcing mass testing and complete lockdowns like the Chinese government did, the Taiwanese government kept offices and shops open and kept public transportation running, but at lower capacity. In recent weeks, those restrictions have lifted, with indoor dining, gyms and tourism sites opening, but many people have stayed home except for essential activities out of concern about another wave.

As of Monday, around 39 percent of Taiwan’s 23.5 million residents have received at least one dose of a vaccine, according to a New York Times tracker, and a locally developed vaccine will be available starting next week.

China, which claims the self-ruling democracy as its territory, has been more forceful in response to recent flare-ups of cases driven by the more contagious Delta variant. Beijing has punished dozens of officials, saying that they mishandled local outbreaks, and has rejected suggestions that it abandon its “zero case” policy.

A local government in the southern Chinese province of Yunnan closed all roads leaving the city after three new locally transmitted cases were reported there last month. In hard-hit eastern cities, including Nanjing and Yangzhou, the authorities have conducted at least seven rounds of mass testing and residents have been ordered to stay home.

Visitors to the Isle of Wight can walk the 68 miles of coastline.

For the second year running, a hallowed rite for millions of people in Britain — decamping to the warmer climate of the Mediterranean — has been disrupted by the pandemic. The number of flights in and out of Britain are half their 2019 levels.

This year, the Isle of Wight, a small island off the south coast of England, has lured even more visitors to its sandy beaches, coastal walks and arcades. But pandemic restrictions, staff shortages and the often uncooperative British weather have presented challenges to visitors and business owners this season.

Like many popular British vacation spots, such as Cornwall and the Lake District National Park, the Isle of Wight is suffering from a shortage of workers, especially in hotels and restaurants. One problem is that many have had to isolate for 10 days after being pinged on the country’s coronavirus tracing app.

And many workers, seeking more secure work, have taken jobs in other sectors. Brexit hasn’t helped — the pool of European Union nationals working in Britain has shrunk by the hundreds of thousands.

As a result, small businesses on the island are unable to fully benefit from the rise in visitors. They are wary of overextending and not having enough workers to meet demand. Instead, they are restricting how many people they serve and limiting the hours they are open.

Gov. Ron DeSantis of Florida in Pensacola last year.
Credit…Mandel Ngan/Agence France-Presse — Getty Images

The chairwoman of the Broward County School Board in Florida said on Sunday that the district had no choice but to defy Gov. Ron DeSantis’s ban on mask mandates.

“We’re living out the nightmare of the Covid pandemic, where so many people in our county, including members of our staff and others, are being impacted,” said Rosalind Osgood, who heads the school board, on the CBS program “Face the Nation.”

Florida’s cases are soaring. The state reported a seven-day rolling average of 21,706 new daily cases on Saturday amid the worst surge of the pandemic. Deaths and hospitalizations are spiking, yet the number of tests administered has decreased.

Broward County has lost two teachers and an educational assistant to complications from Covid-19, Dr. Osgood said. The school board imposed a mask mandate for students, staff members and visitors; a doctor’s note is required for student exemptions.

“We believe that we have a constitutional obligation to protect the lives of our students and staff,” Dr. Osgood said.

After Mr. DeSantis threatened to withhold school funds, the Biden administration stepped in. Officials said they supported the mask mandate and would allow the schools to use funds from pandemic relief measures to replace the salaries.

“It was very encouraging to get the support of the White House during this very, very difficult time that we find ourselves in,” Dr. Osgood said.

Educators in Florida are aware of the negative impact of so much time away from in-person schooling for many students, including mental health risks and declining academic performance, she said. That made the mask mandate all the more important, along with on-site testing measures, vaccination access and air filtration.

“We’ve been working extremely hard to put these in place, and we’re not going to risk their lives by allowing it to be optional,” Dr. Osgood said.

Other states have imposed similar bans on mask mandates. Recently, the Arkansas governor said he regretted approving such a ban and hamstringing schools’ ability to protect students under 12, who cannot yet be vaccinated.