Dutch health officials said on Sunday that they had found at least 13 cases of the Omicron coronavirus variant among 61 infected passengers who had arrived in the Netherlands from South Africa on Friday. The new cases were a clear sign that the virus was crossing borders even as governments imposed new travel restrictions and flight bans.
Additional cases could emerge, as health officials were still examining test samples, said Hugo de Jonge, the country’s health minister, adding that the people who tested positive were isolating. The 61 passengers who had tested positive were among more than 500 who arrived on two separate flights.
A growing list of countries is scrambling to respond to the new, highly mutated version of the virus, which was first detected in Botswana and South Africa and which has sent ripples of panic through governments and markets. Health officials in Australia and Denmark on Sunday both confirmed cases of the Omicron variant in travelers recently arriving from southern Africa. Morocco said Sunday it would ban all incoming flights for at least two weeks beginning Monday amid concerns about Omicron, according to a government statement on state-run news media. The flight ban prevents both foreign nationals and Moroccan citizens from entering.
And British health officials said Sunday a third case had been detected in an individual who had spent time in Westminster, in central London. They said the case was linked to travel to southern Africa.
The World Health Organization warned on Friday that Omicron was a “variant of concern,” the most serious category the agency uses for such tracking, and said that its numerous genetic mutations could help it spread more quickly, even among vaccinated people.
Scientists cautioned that relatively little is known about the new variant, and that only a small number of confirmed cases have surfaced globally. Still, there are worries that Omicron could have spread more widely before scientists in South Africa discovered it last week, and the memories of the rampaging spread this year of the Delta variant have prompted new waves of travel restrictions, aimed primarily at southern African countries.
Britain, Italy, Belgium, the Netherlands and Israel are among the countries that have identified Omicron cases in recent days and imposed new travel restrictions. In a sign of how seriously the authorities in Europe, which is already battling a surge of coronavirus cases, are taking the new threat, officials in France on Friday also suspended arrivals from seven southern African countries even though the new variant had not yet been detected in France.
“It’s probably a question of hours, let’s be honest,” Olivier Véran, the health minister, told reporters on Sunday at a vaccination center in Paris. But he added that “new variant doesn’t necessarily mean new wave, or that the variant is more dangerous.”
“To be safe, we are acting as though this variant is potentially dangerous,” he said.
The European Union is restricting travel to and from seven countries in southern Africa — Botswana, Eswatini, Lesotho, Mozambique, Namibia, South Africa and Zimbabwe — while the United States and South Korea have targeted those countries and Malawi. Britain has restricted travel with those eight nations and Angola, Mozambique and Zambia.
Israel announced the world’s strictest ban to date, sealing its borders to all foreigners for 14 days after one case was confirmed in the country.
Scientists were careful to note that the extent of the threat from Omicron remained unclear, and that existing vaccines were likely to protect against it. Although some variants of concern, like Delta, have lived up to initial worries, others have had a more limited impact.
Some experts, including the W.H.O., said that the rush to reintroduce travel bans and border closures was premature and would unfairly punish African countries that have already suffered from delayed and insufficient vaccine supplies caused in large part by Western countries hoarding doses.
In Australia, officials said that Omicron was detected in two travelers who flew into Sydney on Saturday evening on a Qatar Airways flight from Doha. They were asymptomatic and fully vaccinated, according to a statement from the health authority in New South Wales State. The travelers were placed into quarantine.
In Denmark, officials said that Omicron was detected in two travelers who had recently arrived from South Africa. Both are in isolation, and close contacts are being tracked down, according to a statement by the State Serum Institute, Denmark’s infectious disease authority.
“This was expected, and our strategy is therefore to continue intensive surveillance of the infection in the country,” said Henrik Ullum, the institute’s chief executive. “We want to accelerate the process so that we can vaccinate as many people as possible and get further through the winter before it arrives in Denmark in earnest, as we suspect it will.”
Stephen Castle and Aida Alami contributed reporting.
In the rush to understand the threat posed by the Omicron variant, the worrisome new version of the coronavirus, some experts are pointing hopefully to early signs that it may cause only mild illness, without some of the trademark symptoms of Covid.
But it is far too early to assume that the variant will not cause severe illness, too, warned Dr. Richard Lessells, who coordinates clinical and epidemiological data for the South African Covid Variant Research Consortium.
Many of the early infections in South Africa were spotted among younger people more likely to experience mild illness, he said. The picture may change as the virus spreads through the larger population.
At the moment, the variant has been spotted in at least a dozen countries, including Britain and the Netherlands. Many others are closely monitoring cases. Omicron has not yet surfaced in the United States, according to the Centers for Disease Control and Prevention.
Omicron has dozens of new mutations, including many that may enable the virus to be more contagious and to sidestep immune defenses. But Dr. Angelique Coetzee, who chairs the South African Medical Association, noted on Saturday that the nation’s hospitals were not overrun by patients infected with the new variant, and that most were not fully immunized.
Moreover, most patients she had seen did not lose their sense of taste and smell, and had only a slight cough, she told reporters.
But that may not be as reassuring as it sounds. Most of South Africa’s cases were initially found in the Gauteng province, mostly among younger people at universities and higher education institutions, said Dr. Lessells, who is also an infectious disease physician at the University of KwaZulu-Natal.
“We would of course expect the vast majority of those to be mild cases anyway, regardless of vaccination status,” he said.
In addition, cases overall have also been rising only in the last two weeks, Dr. Lessells noted: “There’s even barely enough time for infections to have had time to progress to severe disease and hospitalization.”
Should Omicron cause severe illness, that will become apparent if there is a significant rise in hospitalizations over the next week or two, he added.
Scientists have not yet analyzed infections in fully immunized people, but they are already seeing some cases of reinfection that suggest the variant can overcome natural immunity, Dr. Lessells said.
He and his colleagues plan to review the latest data on Monday to spot trends and to plan for Omicron’s spread.
On the face of it, the emergence of the Omicron variant is the unhappy fulfillment of expert predictions that the failure to prioritize vaccinations for African countries would allow the coronavirus to continue to circulate and mutate there, imperiling the world’s ability to move beyond the pandemic.
As Western nations kept most of the global vaccine supply for themselves, African countries were denied access to doses or could not afford them. Just over 10 percent of people in Africa have received one dose of a vaccine, compared with 64 percent in North America and 62 percent in Europe.
But the problem is changing shape. In recent weeks, vaccines have started to flow into Africa, and the new challenge is how to rapidly scale up vaccinations — as South Africa demonstrates.
“We haven’t completely overcome the problem of vaccine supply to lower-income countries,” said Shabir Madhi, a virologist at the University of the Witwatersrand in Johannesburg. “But where they are available, countries are struggling to scale up.”
Scientists in South Africa, which has the most sophisticated genomic sequencing facilities on the continent, were the first to announce the detection of the new variant, after it was first found in four people in Botswana.
South Africa has a better vaccination rate than most countries on the continent: Just under one quarter of the population has been fully vaccinated, and the government said it has over five months’ worth of doses in its stores. But they are not being administered fast enough.
Vaccinations in South Africa are running at about half the target rate, officials said last week. To prevent vaccines from expiring, the government has even deferred some deliveries scheduled for early next year.
But the problem is not just a product of the misinformation-driven hesitancy that has plagued vaccination efforts in the West — in fact, some studies suggest it’s a small part of the problem in South Africa.
Instead, the inoculation campaign has been slowed by a complex range of logistical, financial and even political issues. And Western actions are partly to blame.
Many African countries lack the cold storage facilities or logistics chains for a large scale vaccination campaign. Dilapidated health systems mean a lack of clinics or qualified personnel to administer vaccines.
With Western countries hogging vaccine supplies for most of this year, and doses from India halted as cases surged in there, many African countries have relied on donations. But some of those vaccines have landed close to their expiration date, giving countries a narrow window in which to safely deliver them.
And many Africans are constrained by time and money. They may lack the bus fare to reach a distant vaccination center — or be reluctant to stand in line for hours if there’s a risk of missing work, or losing a job.
Misinformation and cultural factors matter, too. Africa has a long history of vaccinating young children against diseases like polio, but a mass vaccination drive among adults is “very, very unusual,” Dr. Matshidiso Moeti, the World Health Organization’s Africa director, told reporters last week.
Even nurses and doctors are prone to believing false tales of dangerous side effects: Recent studies in Ghana and Ethiopia found that fewer than 50 percent of health workers intend to get vaccinated, Dr. Moeti said.
In South Africa, race is a factor: Researchers at the University of Johannesburg found that white people were more vaccine hesitant than Black people — but were more likely to have been inoculated because they had access to better health care.
The race to vaccinate Africans is progressing. In the past eight weeks, 30 African countries have administered 80 percent of doses received, according to the World Health Organization. Only Djibouti and the Democratic Republic of Congo administered fewer than 20 percent of doses received.
Still, there is a long way to go. So far, wealthy countries have delivered just 14 percent of the 1.7 billion doses promised to low- and middle-income countries by next September, according to data collated by Our World in Data, a project at Oxford University.
And no matter how quickly those doses arrive, experts say African countries need support to help get them into people’s arms.
In Kenya this month, the Secretary of State Antony J. Blinken outlined measures to help Kenyans overcome such “last mile” obstacles through the Global Covid Corps, a new public-private partnership aimed at overcoming logistical and delivery hurdles. As fear of the new variant spreads, the sense of urgency around such programs is likely to grow.
At least 13 people who arrived in the Netherlands on two flights from South Africa on Friday were infected with the Omicron variant of the coronavirus, and more cases will most likely be found, Dutch health officials said on Sunday.
Coen Berends, a spokesman for the Dutch public health institute that tracks the virus, added that the Omicron variant might already have been brought to the country by other recent travelers.
“The most important thing is that we know that this variant is in the Netherlands,” Mr. Berends said.
On Friday, health officials tested about 600 passengers who arrived at Amsterdam’s Schiphol Airport on two flights and found 61 to be positive for the coronavirus. Those who tested negative were allowed to quarantine at home or continue their journeys. Those who tested positive were ordered to isolate at home or in designated hotels and will be fined if they violate the measures, Mr. de Jonge said.
The Netherlands joined other Western countries in instituting travel rules, limiting travel from southern Africa to European Union citizens only. But in an acknowledgment that the new variant may have arrived in the country earlier, the government has implored recent travelers from southern Africa to get tested.
The two flights, from Johannesburg and Cape Town, landed within about a half an hour of one another before noon local time on Friday. Health officials took the passengers to a deserted departure bay to be tested, a process that took several hours as they waited together in close quarters, many of them unmasked, said Stephanie Nolen, a global health reporter for The New York Times who was on one of the flights.
In total, the passengers, negative and positive, spent about 30 hours together in the plane and in poorly ventilated rooms. While the infected passengers were told to isolate, those who tested negative were allowed to fly onward and “scattered to the world” despite their exposure, Ms. Nolen said.
Cases have been rising quickly in the Netherlands, which recently announced a lockdown that starts at 5 p.m. and other measures to prevent spread of the virus.
The cascade of travel closures sparked by the emergence of the Omicron variant has triggered resentment among Africans who believed that the continent was yet again bearing the brunt of panicked policies from Western countries, which had failed to deliver vaccines and the resources needed to administer them.
Richer countries, having already hoarded vaccines for much of 2021, were now penalizing parts of the world that they had starved of shots in the first place, scientists said.
“Told you so,” said Francois Venter, a researcher at University of the Witwatersrand in Johannesburg, referring to warnings from African researchers that delaying vaccinations there risked the emergence of new variants. “It feels like these rich countries have learned absolutely nothing in terms of support.”
The sense of outrage was most visceral in South Africa, where business leaders predicted that travel bans by Western nations would inflict a dire economic toll, especially on tourism. In the arrivals halls of Johannesburg’s O.R. Tambo International airport, Ronald Masiwa, a tour operator, watched with dread as the information board flipped to red, displaying cancellation notices. Three clients had already canceled trips overnight, and he feared that many more would follow.
In South Africa, December is traditionally the high season for tourism, one of the country’s biggest industries, and operators had been banking on a surge in visitors from Britain, which had removed South Africa from its “red list” only last month.
“This is devastating,” said David Frost, chief executive officer of the Southern Africa Tourism Services Association. “Many companies have been hanging on by their fingernails, and this is going to wipe them out. It’s going to be dire for conservation, and it’s going to be dire for people in rural areas where tourism is the only economic generator.”
South Africa’s number of daily infections — 2,828 on Friday — was a small fraction of case counts in countries with similarly sized populations, like Germany and Britain, not to mention the United States. For Mr. Frost, the hurried measures were the mark of a blatant double standard.
In South Africa, most of the 22 cases of the Omicron variant detected as of Saturday were in Pretoria, the capital city north of Johannesburg. With fears growing that the government would announce a new lockdown, a sense of foreboding hung over one shopping mall, festooned with Christmas decorations, where Mary Njuguna sells beaded jewelry and woven handbags.
The pandemic had already caused the price of imports to soar, and goods from Kenya and Malawi that once arrived in one week now took months, she said. Talk of a new lockdown made her fear what might come next.
“It’s a big, big mess,” Ms. Njuguna said.
The travel bans resonated widely in a continent where they were seen as a mark of Western double standards. Nanjala Nyabola, a Kenyan writer, said that border closures appeared to be dictated by politics and not public health concerns.
“If you look at the way the numbers are going, we should be thinking about bans on Europe and United States,” she said. “But the border closures are not tied to the public health crisis in front of us.”
British health officials said Sunday that a third case of the new Omicron coronavirus variant had been discovered in the country, in an individual who had spent time in central London. The announcement came just hours after the health secretary, Sajid Javid, rejected calls for tougher restrictions on daily life.
The health security agency said the individual had spent time in the Westminster section of London, but was no longer in the country, and that contact tracing was being performed. It said the case was linked to travel in southern Africa.
Dr. Jenny Harries, chief executive of the agency, said it was “very likely’’ there would be more cases in the coming days.
On Saturday, a day after the government learned of the first two cases, Prime Minister Boris Johnson said that masks would be mandatory on public transportation and in shops in England starting on Tuesday. Tighter testing rules for travelers arriving from abroad would also go into effect that day.
But the government has rejected the idea of ordering people to work from home where possible, introducing vaccine passports in England or requiring masks in restaurants. “This is about taking proportionate action against the risks we face,” Mr. Javid told the BBC on Sunday, speaking before the third case was confirmed.
Britain began suspending flights from six southern African nations on Friday, but some travelers had already arrived in London by the time the measure took effect.
Mr. Javid acknowledged that passengers landing on Friday were not tested at the airport and were able to leave as usual, including by public transport. He said that all travelers who had arrived from southern Africa within the past 10 days were being contacted and asked to take tests.
“We could not have acted more swiftly,” he said.
By contrast, in Amsterdam, Dutch health officials tested more than 500 passengers who arrived on Friday on two flights from South Africa. Those who were negative were allowed to leave the airport and quarantine at home, or to continue their journeys.
Mr. Javid also urged Britons to quickly get booster shots and said he expected advice “imminently” from scientific experts on expanding the scope of the country’s vaccine program, especially with regard to boosters.
Such measures would, he added, help to “protect the progress we have made so we can continue to look forward to Christmas with family and friends.”
Scientific experts at the World Health Organization warned on Friday that a new coronavirus variant discovered in southern Africa was a “variant of concern,” the most serious category the agency uses for such tracking.
The designation, announced after an emergency meeting of the health body, is reserved for dangerous variants that may spread quickly, cause severe disease or decrease the effectiveness of vaccines or treatments. The last coronavirus variant to receive this label was Delta, which took off this summer and now accounts for virtually all Covid cases in the United States.
The W.H.O. said the new version, named Omicron, carries a number of genetic mutations that may allow it to spread quickly, perhaps even among the vaccinated.
Independent scientists agreed that Omicron warranted urgent attention, but also pointed out that it would take more research to determine the extent of the threat. Although some variants of concern, like Delta, have lived up to initial worries, others have had a limited impact.
William Hanage, an epidemiologist at the Harvard T.H. Chan School of Public Health, and other researchers said that vaccines will most likely protect against Omicron, but further studies are needed to determine how much of the shots’ effectiveness may be reduced.
As the coronavirus replicates inside people, new mutations constantly arise. Most provide the virus with no new advantage. When worrisome mutations do emerge, the World Health Organization uses Greek letters to name the variants. The first “variant of concern,” Alpha, appeared in Britain in late 2020, soon followed by Beta in South Africa.
Omicron first came to light in Botswana, where researchers at the Botswana Harvard H.I.V. Reference Laboratory in Gaborone sequenced the genes of coronaviruses from positive test samples. They found some samples sharing about 50 mutations not found in such a combination before. So far, six people have tested positive for Omicron in Botswana, according to an international database of variants.
Around the same time, researchers in South Africa stumbled across Omicron in a cluster of cases in the province of Gauteng. As of Friday, they have listed 58 Omicron samples on the variant database. But at a news conference on Thursday, Tulio de Oliveira, the director of the Centre for Epidemic Response & Innovation in South Africa, said that “close to two or three hundred” genetic sequences of Omicron cases would be released in the next few days.
When the World Health Organization began to name the emerging variants of the coronavirus, officials turned to the Greek alphabet to make it easier for the public to understand the evolution: Alpha, Beta, Gamma, Delta and so on.
Now the alphabet has created its own political headache. When it came time to name the potentially dangerous new variant that has emerged in southern Africa, the next letter in alphabetical order was Nu, which officials thought would be too easily confused with “new.”
The letter after that was even more complicated: Xi, a name that in its transliteration, though not its pronunciation, happens to belong to the leader of China, Xi Jinping. So they skipped both and named the new variant Omicron.
“‘Nu’ is too easily confounded with ‘new,’ and ‘Xi’ was not used because it is a common last name,” a spokesman, Tarik Jasarevic, said on Saturday in an emailed response to questions about skipping the two letters.
The organization’s policy, he went on, requires “avoiding causing offense to any cultural, social, national, regional, professional, or ethnic groups.”
The organization did not initially explain why it jumped from Mu, a lesser variant first documented in Colombia, to Omicron. The omission resulted in speculation over the reasons. For some, it rekindled criticism that the organization has been far too deferential in its dealings with the Chinese government.
“If the WHO is this scared of the Chinese Communist Party, how can they be trusted to call them out the next time they’re trying to cover up a catastrophic global pandemic?” Senator Ted Cruz, the Republican from Texas, wrote on Twitter.
There is no evidence that the Chinese had any say in naming the new variant, known scientifically as the SARS-CoV-2 variant B.1.1.529. Some variants have proved less transmissible, but Omicron could be the most worrisome new version since the Delta.
Throughout the pandemic, the W.H.O. has sought to avoid the once common practice of referring to health threats with geographic terms: Spanish flu, West Nile virus, Middle East Respiratory Syndrome, Zika and Ebola.
That reflected concerns among scientists about the risk of stigmatizing places or peoples, but it was also seen in the early months of the pandemic as deferential to China, which has an influential role in global health affairs.
Chinese officials have reacted angrily to efforts to associate the pandemic with the country or Wuhan, the central city where it first spread in the fall of 2019. China’s fiercest critics in the United States, including then President Donald J. Trump and his aides, persisted anyway, at times using sophomoric and racist slurs.
“The novel coronavirus affects everyone and needs to be tackled with joint efforts, instead of fear-mongering in a xenophobic way,” Geng Shuang, a spokesman for China’s Ministry of Foreign Affairs, said at the time.
At the first BTS concert of the coronavirus era on Saturday, Maggie Larin, 25, and her three friends were surrounded by a roaring crowd of 70,000 other fans in SoFi Stadium in Inglewood, Calif.
But when Lee Hye Su, 23, and her two friends go to see the K-pop group The Boyz in Seoul Olympic Park next weekend, she will be seated silently, masked and socially distanced, alongside only 2,100 other fans, according to the venue’s rules.
As K-pop bands start touring the world and performing for live audiences again, fans in their home country, South Korea, are flocking to stadiums. But they must abide by the government’s strict rules: no shouting, chanting or singing along at concerts with 500 or more attendees.
“We’ll only be able to clap when we enter the hall,” said Ms. Lee, who has followed the band since 2018. She said it was unfortunate that the atmosphere on Saturday would be different from that of past concerts, where she could yell all she wanted.
“But I knew I had to go as soon as I found out about it,” she said.
Live K-pop concerts are returning to South Korea as hospitalizations are rising across the country and the spread of a new variant alarms the world. The health minister, Kwon Deok-cheol, said on Friday that the government was considering tightening some restrictions because the number of available beds for critically ill patients in and around Seoul was “reaching a limit.”
But there is pent-up demand for live performances. K-pop fan groups have remained active throughout the pandemic, said Kim Hong Ki, chief executive of Space Oddity, a South Korean music collective. Record sales for K-pop groups have even spiked, he said.
“In K-pop, fans aren’t ordinary consumers, but active, evangelistic and dedicated to their fandom, almost religiously,” said Mr. Kim, who has worked in the South Korean music industry for decades. “When the rules are relaxed to some extent, fans will be chasing after live shows.”
Several other bands, like NCT 127 and Twice, have scheduled their first pandemic-era concerts in South Korea for next month. And thousands of K-pop fans in the country are dashing for tickets, even if they know those shows could get canceled.
Pandemic rules in the United States require fans to wear masks in concert halls, and provide proof of full vaccination, negative virus test results and photo identification upon entry. Still, the BTS concert in California this weekend was sold out months in advance.
To catch the show, Ms. Larin took a weekend away from law school in Michigan.
“I’ve been spending a lot of time preparing for the actual concert, listening to a lot of their music and learning their fan chants,” she said before the event on Saturday. “It’s going to be a very emotional experience.”
A top-flight soccer game in Portugal produced instead farcical drama on Saturday evening, after one of the teams was forced to field only nine players, including two goalkeepers, because the rest of its squad had been depleted by a Covid-19 outbreak.
In the match between Benfica and Belenenses in Portugal’s top professional league, Benfica’s full-size complement of 11 players dominated, scoring seven goals by halftime. The game was called off during the second half, after one of seven remaining Belenenses players sat down, saying he was unable to continue, reducing his side to six. The rules of the sport require a team to field at least seven players.
Ahead of the game, the virus swept through the Belenenses club, infecting as many as 17 of its players and staff members. One of the players who had tested positive had recently returned from playing in South Africa, where researchers were the first to identify the new Omicron variant of the coronavirus.
The World Health Organization has labeled Omicron a “variant of concern,” saying it could spread more easily than other forms of the virus. It was unclear if the player had been infected with the variant.
The Belenenses players sought to have the game canceled, warning in a joint statement before the match that soccer would have “lost its heart” if they were forced to play such an uncompetitive matchup amid a public health crisis. Officials reportedly told the players that the game must go on.
Players from several other clubs criticized Portugal’s sports authorities for tainting the country’s reputation and that of one of its favorite sports.
The pharmaceutical company Merck said on Friday that in a final analysis of a clinical trial, its antiviral pill reduced the risk of hospitalization and death among high-risk Covid patients by 30 percent, down from an earlier estimate of 50 percent.
The lower efficacy is a disappointment for the drug, known as molnupiravir, which health officials around the world are counting on as a critical tool to save lives and reduce the burden on hospitals. It increases the importance of a similar, apparently more effective, offering from Pfizer that is also under review by the Food and Drug Administration.
A panel of advisers to the F.D.A. is set to meet on Tuesday to discuss Merck’s treatment and vote on whether to recommend authorizing it to treat high-risk Covid patients.
In briefing documents posted to the F.D.A.’s website on Friday, agency reviewers did not take a position on whether the drug should be authorized, though they found that the clinical trial data did not show any major safety concerns and that the drug was effective in preventing severe disease.
The reviewers said they had only become aware of the updated efficacy estimate earlier this week and were still reviewing the data. They said they could update their assessment when the panel meets on Tuesday.
Merck’s initial estimate that the drug reduced hospitalization and death by 50 percent came from an early look at results from 775 study participants. The updated figure announced on Friday came from more than 1,400. In the final analysis, the participants who received molnupiravir had a 6.8 percent risk of being hospitalized, and one patient died. Those who received a placebo had a 9.7 percent risk of being hospitalized, and nine died.
Dr. David Boulware, an infectious disease researcher at the University of Minnesota, said he expected the drug would still receive emergency authorization. If the expert committee endorses it and the F.D.A. heeds the recommendation, the treatment could be authorized in the United States as soon as next week.
“The reduction in hospitalization is a little bit less, but there is still a big mortality benefit if you start early,” he said.
Still, he said, molnupiravir will probably be deemed a lower-tier treatment, an alternative choice for people who can’t get or don’t want more effective treatments.
Monoclonal antibody drugs, which are typically administered intravenously in the United States, have been found to reduce hospitalizations and deaths by at least 70 percent. Pfizer’s antiviral pill, Paxlovid, which was found in a clinical trial to cut the risk of hospitalization and death by 89 percent, could become available within weeks. Fluvoxamine, a common and inexpensive antidepressant, appears to be about as effective as molnupiravir.
Meant to be dispensed at pharmacies and taken at home, Merck’s drug is the first in a new class of antiviral treatments for Covid that are expected to reach many more people than other treatments have. Public health experts say that while the pills are no substitute for vaccination, they have the potential to prevent severe illness and save lives.