Americans who are fully vaccinated against the coronavirus can travel “at low risk to themselves,” both within the United States and internationally, but they must continue to take precautions like wearing a masks in public to avoid possibly spreading the virus to others, federal health officials said on Friday.
The new recommendations mark a modest departure from previous advice. Federal health officials have been urging Americans not to travel at all, unless they absolutely must. That recommendation still applies, Dr. Rochelle Walensky, director of the Centers for Disease Control and Prevention, told reporters at a White House news conference on Friday.
New virus cases, hospitalizations and new deaths have declined significantly since their January peaks, but new infections has remained at a level that health officials say is too high. New deaths on average have only just dipped below 900 a day, according to a New York Times database, and hospitalization numbers have started to level off.
With the case increases in recent weeks, federal health officials are concerned about the potential impact of easing restrictions. Scientists are not yet certain whether, or how often, vaccinated people may become infected, even briefly, and transmit the virus to others. A recent C.D.C. study suggested that it may be a rare event.
Until that question is resolved, many public health officials feel it is unwise to tell vaccinated Americans simply to do as they please. Yet at the same time, Dr. Walensky said on Friday, the agency wished to acknowledge a growing body of evidence suggesting that the risk to vaccinated travelers themselves is comparatively low.
“On the one hand, we are telling you we are worried about rising cases, to wear a mask, and to avoid travel,” Dr. Walensky said. “Yet on the other hand we are saying that if you are vaccinated, evolving data suggests that traveling is likely lower risk.”
Travel has been increasing nationwide as the weather warms and Americans grow fatigued with pandemic restrictions. Last Sunday, for example, marked the busiest day at domestic airports since the pandemic began. Several states have lifted restrictions and mask mandates, beckoning tourists despite rising caseloads in some regions.
Earlier this week, Dr. Walensky warned that the increases left her a recurring sense of “impending doom.” Some scientists predicted weeks ago that the number of infections could curve upward again in late March, at least in part because of the rise of virus variants of the across the country.
President Biden, who previously urged states to maintain or reimpose mask mandates, pleaded with Americans on Friday to continue to follow guidelines from health experts and get vaccinated as soon as they can. Most states have accelerated their timelines for opening vaccinations to all adults, as the pace of vaccinations has increased. As of Thursday, an average of 2.9 million shots a day were being administered, according to data reported by the C.D.C.
“Too many Americans are acting as if this fight is over,” Mr. Biden said. “But this is still April, not July, we are not there yet.”
People are considered fully vaccinated two weeks after receiving the single-dose Johnson & Johnson vaccine, or two weeks after receiving the second dose of the two-dose regimen from Pfizer-BioNTech or Moderna.
Fully vaccinated Americans who are traveling domestically do not need to be tested and do not need to follow quarantine procedures at the destination or on return home, the C.D.C. now advises.
Vaccinated Americans do not need to get a coronavirus test before international travel, unless required to do so by authorities at the destination. Some destinations also may require that vaccinated travelers quarantine after arrival. Vaccinated travelers do not need to quarantine after returning unless required to do so by local officials, the C.D.C. said.
But the C.D.C. says vaccinated Americans traveling internationally are required tohave a negative coronavirus test before boarding a flight back to the United States, and they should get tested against three to five days after their return home.
The recommendation is predicated on the idea that vaccinated people may still become infected with the virus. The C.D.C. also cited a lack of vaccine coverage in other countries, and concern about the potential introduction and spread of new variants of the virus that are more prevalent overseas.
The new advice adds to C.D.C. recommendations issued in early March saying that fully vaccinated people may gather in small groups in private settings without masks or social distancing, and may visit with unvaccinated individuals from a single household as long as they are at low risk for developing severe disease if infected.
The travel recommendations issued Friday do not alter C.D.C. guidelines for the unvaccinated. The agency continues to discourage nonessential domestic travel by those who are not fully immunized, saying that if they must travel, they should be tested for infection one to three days before their trip and again three to five days after concluding their trip.
Unvaccinated travelers should also stay home and self-quarantine for seven days after a trip if they get tested, and quarantine for 10 days if they do not get tested after a trip, the agency said. Both vaccinated and unvaccinated individuals should monitor themselves for symptoms after a trip, and all must wear masks and take other precautions in public.
Many countries, including those in the European Union, still block most Americans from coming. Some are starting to make exceptions for those who are vaccinated. As of March 26, fully vaccinated Americans who can present proof of vaccination can visit Iceland, for example, and avoid such restrictions as testing and quarantine, the country’s government said.
For decades, the European Union has sold itself not just as the best antidote to another European war, but as “the Europe that protects,” arguing that by its collective size and shared sovereignty, it will deliver a better, longer and more prosperous life to all. With its vaccine rollout in chaos, that promise now looks hollow, and risks undermining the bloc’s credibility when it comes to major challenges.
In Belgium, Alain Walravens, 63, is waiting to be invited for a first coronavirus vaccination. So are Marion Pochet, 71, a retired translator, and her husband, Jean-Marc. At least, Ms. Pochet said, they both have had Covid-19, “so we have some immunity, at least for the moment.”
All three are sharply critical of the European Union, which took control of vaccine procurement and distribution and is widely considered to have done worse than its main partners, the United States and Britain, let alone Israel, which have all gotten vaccines into a much larger percentage of their populations than Europe has.
So far, only about 11 percent of the bloc’s population has received at least one vaccine shot, compared with 47 percent in Britain and 30 percent in the United States.
As European countries lock down again in a new wave of the virus, the reputation and credibility of the European Union and its executive arm, the European Commission, are much in play.
“This is the fault of the European Union,” said Mr. Walravens, an events organizer.
“In other countries where the vaccination is going faster, there are real results,” he added. “The number of cases is going down. Here in Belgium, the hospitals are getting saturated.”
Brussels has always taken pride in its technocratic rule setting for the world, but it has just lost Britain, the world’s fifth-largest economy, and even before the pandemic, it was suffering from low growth and a shrinking share of global trade.
After every crisis, whether it was Kosovo or the euro debt disaster, the usual answer is “more Europe.” But unless Brussels can turn matters around quickly, its vaccine crisis may cause member states to resist granting further authority to the European Commission.
“This has been catastrophic for the reputation of the European Union,” said Mark Leonard, the director of the European Council on Foreign Relations.
Even Guy Verhofstadt, a European Parliament member and fierce European federalist, called the Commission’s performance “a fiasco.”
At the start of the crisis, as nations erected borders and hoarded protective equipment, masks and gowns, there was a huge desire for European cooperation, he said, “not because people liked the E.U. or its institutions, but because they were so absent.”
But the question now, he said, is buyer’s remorse. “The E.U. waded into an area with no expertise and competence and put a spotlight on itself,” he said. “In the minds of many who look at the U.K. and U.S. and Israel, they think we’re doing badly because of European cooperation, and that will have a corrosive impact in other areas.”
Britain reported 30 cases of extremely rare blood clots in people who had received the AstraZeneca-Oxford vaccine, the same sort of events that have prompted some European countries to restrict use of the shot in certain at-risk age groups.
The reports represented 25 more cases than Britain’s medicines regulator had previously received, going some way toward addressing a mystery that has hung over safety concerns about the vaccine: why Britain had not observed the same phenomenon that has been seen in continental Europe, driving countries including France, Germany and Sweden to stop giving the shot to younger people, who are believed to be at higher risk from the rare clotting events.
Britain’s medicines regulator said that it had received reports of no such clotting cases in people who had received the Pfizer-BioNTech vaccine.
The clotting cases have generated concern because, scientists said, they were somewhat unusual. They involve blood clots combined with unusually low levels of platelets, a disorder that can lead to heavy bleeding.
The clotting events that have drawn the most concern, known as cerebral venous sinus thrombosis, entail clots in the veins that drain blood from the brain, a condition that can lead to a rare type of stroke. Those represented 22 of the 30 clotting cases that Britain reported this week.
But it is not clear whether any of the cases are linked to the vaccine. And even if they are, British and European regulators have said they were so rare that the vaccine should continue to be used.
Australia’s health authorities are examining a probable case of the same clotting disorder in a 44-year-old man who received the AstraZeneca vaccine around March 22. He has been hospitalized in Melbourne.
On Thursday, Germany’s immunization commission, the STIKO, recommended that anyone younger than 60 who received an initial vaccination with AstraZeneca be given either Pfizer-BioNTech or Moderna shots as their second vaccine doses.
In reporting its updated case count, Britain’s medicines regulator said that “the benefits of the vaccines against Covid-19 continue to outweigh any risks, and you should continue to get your vaccine when invited to do so.” The European Union’s medicines regulator has also recommended that countries continue to use the AstraZeneca vaccine. Both agencies are continuing to investigate.
Scientists said on Friday that the overall risk of the particular clotting events that have drawn concern was extremely low: roughly one case in 600,000 recipients of the AstraZeneca vaccine in Britain. And it is difficult to know how common the cases are in the general population, given that it can be hard to diagnose. Scientists have said that case counts would inevitably rise among vaccinated people as doctors began looking more closely for the condition.
David Werring, a professor at University College London’s Institute of Neurology, said that the unusual presentation of the cases in vaccinated people was creating concern about possible links with the shot.
But, he said, “The key thing to remember is how rare these brain clots are, and how powerful the proven benefit of vaccination is against Covid.” He added that doctors and people who had received the AstraZeneca vaccine should be on the lookout for symptoms of the clotting events, like severe headaches or signs of a stroke.
“More research is urgently needed,” he said.
Melissa Eddy contributed reporting.
Federal regulators announced Thursday night that they had authorized Moderna to put 50 percent more coronavirus vaccine into its vials, a decision that is expected to lift the nation’s vaccine stock.
The decision provides new assurance of Moderna’s supply and could speed up its deliveries. Like Pfizer, another manufacturer of a two-dose vaccine, Moderna has pledged to deliver a total of 200 million doses by the end of May and 300 million by the end of July.
Moderna had already begun producing fuller vials in anticipation of the Food and Drug Administration’s decision.
The agency told Moderna six weeks ago that it favored increasing the amount of vaccine in vials that it had previously authorized for 10 doses. In a statement, the company said it expects to begin shipping 15-dose vials within weeks.
The F.D.A.’s ruling comes one day after revelations of a setback to the Biden administration’s vaccine rollout. A factory mix-up ruined up to 15 million doses of Johnson & Johnson’s one-shot vaccine, and has delayed F.D.A. authorization of the Baltimore plant where that vaccine is being manufactured.
Although Johnson & Johnson has said it will still be able to deliver 24 million doses this month, as promised, all shipments from that plant have been delayed while the F.D.A. investigates and decides whether to certify production lines there.
Federal officials have been counting on Johnson & Johnson to round out the nation’s vaccine supply. President Biden has promised enough doses for all the nation’s adults by the end of May.
F.D.A. regulators also decided to allow health practitioners to administer an 11th dose of Moderna’s vaccine if they were able to extract it out of vials previously designated for only 10 doses.
But the agency noted that unless practitioners use specialized syringes and needles, they might not to be able to extract that 11th dose. They may also be limited to only 13 shots from Moderna’s 15-dose vials.
Those specialized syringes have been in short supply for months.
Moderna was able to quickly modify one or more of its production lines because, while it poured more liquid into the vials, the size of vials themselves remained the same. All three of the nation’s federally authorized vaccine manufacturers have been able to produce more vaccine substance than they have been able to bottle in the so-called fill-and-finish phase.
In its statement, Moderna said that filling the vials with more vaccine was a way to relieve that bottleneck and accelerate production.
The mishap with Johnson & Johnson’s vaccine occurred at a Baltimore plant run by Emergent BioSolutions, a subcontractor. Workers there accidentally contaminated Johnson & Johnson’s doses with an ingredient used to produce a different vaccine developed by AstraZeneca. AstraZeneca’s vaccine has not been authorized for distribution in the United States. Emergent manufactures both vaccines at the same plant.
Federal officials attributed the mistake to human error. On Thursday, Emergent executives told employees that the entire lot of vaccine substance — the equivalent of up to 15 million doses — would be discarded.
Emergent issued a statement Thursday saying, “Discarding a batch of bulk drug substance, while disappointing, does occasionally happen during vaccine manufacturing.” The company said the error had been detected through “rigorous quality checks.”
Johnson & Johnson on Friday became the third company to enter the race to expand the use of its coronavirus vaccine to adolescents. Researchers have begun testing the drug maker’s vaccine in adolescents 12 to 17 years old, the company announced.
Johnson & Johnson has been lagging its competitors. Pfizer and BioNTech announced on Wednesday that their coronavirus vaccine is extremely effective in young adolescents, perhaps even more so than in adults. Results from a similar trial of Moderna’s vaccine are expected in the next few weeks.
Pfizer, BioNTech and Moderna are also testing their vaccines in children younger than 12. Johnson & Johnson has said it would wait for results from trials in older children before following suit.
A single-shot version of Johnson & Johnson’s vaccine was authorized in February by the Food and Drug Administration for use in adults, and is now being tested on adolescent subjects. Made by Janssen Pharmaceuticals, a subsidiary, the vaccine is authorized in Canada and many other countries. But a mix-up in ingredients at a Baltimore factory may delay future shipments of doses in the United States while the Food and Drug Administration investigates what occurred.
Since September, Johnson & Johnson has also been assessing the safety and efficacy of a two-dose regimen in adults 18 and over. That study now also includes adolescents, the company said.
“The Covid-19 pandemic has had a profound impact on adolescents, not just with the complications of the disease, but with their education, mental health, and well being,” Dr. Paul Stoffels, Johnson & Johnson’s chief scientific officer, said in a statement. “It is vital that we develop vaccines for everyone, everywhere, to help combat the spread of the virus with the goal to return to everyday life.”
As of Wednesday, 30 percent of all Americans had received at least one dose of a coronavirus vaccine, and 17 percent had been fully inoculated, according to data collected by the Centers for Disease Control and Prevention.
But children under 18 account for about 23 percent of the population in the United States, and the country cannot hope to reach herd immunity — the point at which the virus begins to run out of vulnerable hosts — without protecting them, some experts have said.
A day after pushing back the Mets’ season-opening game in Washington because of a coronavirus outbreak on the Nationals, Major League Baseball postponed the teams’ three-game weekend series on Friday. The league said it needed more time for follow-up testing and contact tracing after four Nationals players tested positive this week.
The Mets now will play their first game of the season on Monday in Philadelphia, several hours after the Nationals are scheduled to host the Atlanta Braves. Baseball officials are hopeful that the Nationals will be cleared to play by then, as long as their players continue to test negative during the layoff.
If the Nationals do start on Monday, their roster will be significantly compromised. The players who tested positive cannot return until at least 10 days from their positive tests, and those in close contact must miss at least seven days. The Nationals could fill those roster spots with players from their minor-league system.
For M.L.B., last summer’s outbreaks on the Miami Marlins and the St. Louis Cardinals highlighted the importance of contact tracing to containing the spread of the virus. Players are given wearable devices now to help identify close contacts.
Baseball officials said on Friday that the league had conducted 14,354 tests in the past week, with only four positives — three Nationals players and one staff member who is not with the Nationals — through Thursday. A fourth Washington player tested positive on Friday.
Since the start of spring training, M.L.B. said that it has administered 92,896 tests — counting monitoring and intake testing — and found 38 total positives (28 players and 10 staff members), for a positive rate of .04 percent.
Shoots of budding optimism pop up almost daily in New York City after one of the hardest years in its history.
The Mandarin Oriental Hotel overlooking Central Park called back workers for a reopening this week. Union Square Café, a popular Manhattan restaurant that had been closed for months, is feeding diners again. When the Yankees opened their season in the Bronx on Thursday, fans were back in the stands, though limited to one-fifth of the seats.
It may take some time, said Mark Zandi, chief economist at Moody’s Analytics. but “the city is going to see a big revival.”
It will not be easy.
By many measures, the most populous city in the United States suffered some of the greatest losses in the Covid-19 pandemic, and it faces one of the longest and steepest climbs back. Shows will not return to Broadway stages until after Labor Day. Many workers will not begin commuting to the office and buying lunch at the corner deli for months — if they return at all.
But for the first time since the city went into lockdown late last March, there are palpable signs of rebirth, fueled by a growing supply of coronavirus vaccines and an impending gusher of federal aid to City Hall, the schools, the transit system, restaurants and theaters.
In Manhattan, a year after Covid-19 cratered the sales market, the borough appears poised for a recovery, thanks to price cuts, renewed confidence in the city and a surge of first-time home buyers.
“Yes, the market is recovering,” said Jonathan J. Miller, the president of the appraisal firm Miller Samuel. “But we can’t oversell and say it’s some sort of boom — it’s just dramatically better than it was a quarter or two ago.”
The city’s outlook has improved as a result of the latest stimulus bill, financial analysts say, which included about $6 billion in direct aid to the city government, $6.5 billion to the Metropolitan Transportation Authority and $4 billion to the city’s public schools.
The federal aid will help address some of the city’s biggest short-term problems, including huge drops in revenue from property and sales taxes and fares that the M.T.A., which runs the subway, buses and two commuter rails, is heavily dependent on.
Still, the road to full recovery is strewn with challenges, business leaders and analysts say.
Entire industries, including the arts and the hotel and restaurant sectors, were decimated, with thousands of businesses closing for good. Tourism, a pillar of the economy, is years away from rebounding, according to forecasts. And many companies are making at least some remote work a permanent feature, raising questions about the future of Manhattan without legions of office workers.
“The city still has a ways to go,” said Ana Champeny, director of city studies for the Citizens Budget Commission. “You’ve got to get commuters back in Midtown and downtown, the business district. You’ve got to get restaurants and theaters reopened.”
The New York metropolitan area lost more than one million jobs in 2020, close to double the Los Angeles area’s loss and triple the Chicago area’s, according to the federal Bureau of Labor Statistics. Low-paying jobs that cannot be done from home accounted for most of the losses, and many may not come back for years, if ever, economists said.
New York’s economy was especially vulnerable to the pandemic because of its heavy reliance on tourists and business travelers to fill hotel beds and seats in restaurants, theaters and stadiums. The number of foreign visitors to New York is not expected to reach its 2019 level before 2025, according to the city’s tourism promotion agency.
BRUSSELS — In an April Fool’s Day joke that went wrong, a fake announcement of a music festival contributed to thousands gathering in a major park in Brussels on Thursday in defiance of Covid-19 restrictions. As the police confronted the crowd, several officers and participants were wounded, and four people were arrested.
The unusually warm weather in the city would most likely have drawn people to the park in higher numbers, but the prank added to the density. The level of frustration, particularly among younger people, is high in Belgium, as new Covid-19 cases are increasing and hospitals become saturated despite months of restrictions.
The hoax festival, announced on Facebook and called “La Boum,” a slang word in French for a party, promised the appearance of famous DJs, including David Guetta, and claimed that no coronavirus rules would be followed.
The organizers noted that the festival was a hoax, but, according to the police, 1,500 to 2,000 people still gathered in the park, Bois de la Cambre, on Thursday afternoon, after tens of thousands registered on Facebook their interest in the event. Despite several warnings, the police said, the attendees refused to leave, and some chanted “Freedom!” and threw bottles. The police used water cannons and sent in mounted officers to disperse the crowd.
Belgium has been in a semi-lockdown since October, with restaurants and bars closed, and rules requiring residents to work from home and limiting social contacts to one person per household. Up to four people are allowed to meet outside, as long as they wear face masks and respect social-distancing rules. Last week, in response to an increasing number of new cases and a rise in the number of hospitalized patients, the Belgian authorities tightened the rules, ordering hairdressers and beauty salons to close and allowing nonessential stores to serve customers by appointment only.
Prime Minister Alexander De Croo posted on Twitter that the gathering in Brussels was “totally unacceptable.”
“All support to the injured police officers,” he added. “I understand everyone is tired of corona. But the rules are there for a reason, and they are binding for everyone. Hospitals are filling up. Solidarity now is the key to freedom tomorrow.”
Annelies Verlinden, the Belgian interior minister, acknowledged that “for many people, especially the young ones, the Covid crisis is now lasting a very long time.” But she said that the gathering in Brussels was “a slap in the face for all those who are doing their best to respect the coronavirus measures.”
On Wednesday, a Brussels court ordered the Belgian government to lift all Covid-19 restrictions, ruling that the measures did not have a legal basis because they had been instituted by ministerial decrees. But the court gave the government 30 days to remedy the situation, and a special pandemic law is currently being debated in Parliament.
Stranded overseas for months because of travel restrictions, three Australians have filed a complaint with the United Nations Human Rights Committee, arguing that the Australian government is violating their right to return home.
Australia’s strict border closures have helped keep the coronavirus largely off its shores, in part by imposing a cap on the number of passengers who can fly in from overseas. That limit extends to citizens, meaning that tens of thousands of Australians remain unable to travel home. And after Prime Minister Scott Morrison failed to make good on a pledge to get “as many people home, if not all of them,” by last Christmas, anger is mounting among those who feel abandoned by their government.
“By going to the U.N., we hope to highlight what an unfeeling government Mr. Morrison heads,” said Deborah Tellis, spokeswoman for the petitioners.
The petition filed on Monday argues that by limiting the number of passengers who are allowed into Australia to about 6,000 per week, the government is violating the United Nations’ International Covenant on Civil and Political Rights, which states that a person cannot be “arbitrarily deprived of the right to enter his or her own country.”
Australia is one of the few countries in the world that have imposed such pandemic restrictions on their own citizens. The government has framed its hard-line approach as necessary because of limited quarantine facilities, and said it has been critical to avoiding the large-scale coronavirus outbreaks seen in other countries.
It’s not clear what effect the petition will have. Some legal experts say that the U.N. committee cannot compel Australia to bring people home, and that the passenger limits do not represent an outright ban on citizens from returning.
But Australians stranded overseas lack other avenues for recourse, Ms. Tellis said.
The petitioners are being advised by international human rights lawyer Geoffrey Robertson, who is also known for being WikiLeaks founder Julian Assange’s lawyer.
Ms. Tellis said she had been working as a teacher in India last June when she and her daughter packed up and prepared to return to Australia. Their plans were scuppered at the last minute when her daughter became infected with the coronavirus. For nine months, they made airline bookings only to be bumped off again and again when flights were canceled or the caps were changed. They alternated between couch surfing with friends and living in Airbnbs.
“It was horrible, living in limbo,” Ms. Tellis said. “Finally, I just went into a bit of a, not a mental breakdown, but I was crippled with anxiety and having to see a psychologist.”
They were finally able to secure a flight back last month. She estimates the ordeal cost her 20,000 Australian dollars, or about $15,000.
As of last week, more than 36,000 Australians overseas had registered with the Department of Foreign Affairs and Trade saying they wanted to come home. But advocates for those stranded say that the real number is most likely higher. Some, like Josh Simons, have declined to register because, to do so, they must sign a waiver that prevents them from taking legal action against the government.
“Going on that list means you’re basically agreeing that Australia has done everything it can to do right by you, which I can say as a stranded Aussie is just not the case,” he said.
Mr. Simons, chief executive of the tech start-up Vampr, was in Australia at the start of the pandemic. But when his wife living in New Jersey lost her two jobs, he flew to the U.S. to support her. They’ve been trying to return to Australia ever since.
Mr. Simons stressed that he was proud of the way Australia had been able to contain the virus. But intertwined with that is a creeping sense that his citizenship doesn’t guarantee him the right to return to his country.
“I never thought the possibility of feeling like citizenship had zero value would happen in my lifetime,” he said. “I wouldn’t have dreamt in my wildest of dreams that I couldn’t come home.”
The Centers for Disease Control and Prevention on Thursday walked back contentious comments made in a TV interview by its director, Dr. Rochelle P. Walensky, suggesting that people vaccinated against the coronavirus never become infected or transmit the virus to others.
The assertion called into question the precautions that the agency had urged vaccinated people to take just last month, like wearing masks and gathering only under limited circumstances with unvaccinated people.
“Dr. Walensky spoke broadly during this interview,” an agency spokesman told The New York Times. “It’s possible that some people who are fully vaccinated could get Covid-19. The evidence isn’t clear whether they can spread the virus to others. We are continuing to evaluate the evidence.”
The agency was responding in part to criticism from scientists who noted that current research was far from sufficient to claim that vaccinated people cannot spread the virus.
The data suggest that “it’s much harder for vaccinated people to get infected, but don’t think for one second that they cannot get infected,” said Paul Duprex, director of the Center for Vaccine Research at the University of Pittsburgh.
In her television interview, with Rachel Maddow on MSNBC, Dr. Walensky had referred to data published by the C.D.C. showing that one dose of the Moderna or Pfizer-BioNTech vaccine was 80 percent effective at preventing infection, and two doses were 90 percent effective.
That certainly suggested that transmission from vaccinated people might be unlikely, but Dr. Walensky’s comments hinted that protection was complete. “Our data from the C.D.C. today suggests that vaccinated people do not carry the virus, don’t get sick,” she said. “And that it’s not just in the clinical trials, it’s also in real-world data.”
Dr. Walensky went on to emphasize the importance of continuing to wear masks and maintain precautions, even for vaccinated people. Still, the brief comment was widely interpreted as saying that the vaccines offered complete protection against infection or transmission.
In a pandemic that regularly spawns scientific misunderstanding, experts said that they were sympathetic to Dr. Walensky and her obvious desire for Americans to continue to take precautions.
“What we know is the vaccines are very substantially effective against infection — there’s more and more data on that — but nothing is 100 percent,” said John Moore, a virologist at Weill Cornell Medicine in New York. “It is an important public health message that needs to be gotten right.”
All of the coronavirus vaccines are spectacularly successful at preventing serious disease and death from Covid-19, but how well they prevent infection has been less clear.
Clinical trials of the vaccines were designed only to assess whether the vaccines prevent serious illness and death. The research from the C.D.C. on Monday brought the welcome conclusion that the vaccines were also extremely effective at preventing infection.
JOHANNESBURG — Regulators in South Africa, which has been struggling with a highly transmissible variant of the coronavirus, approved the Johnson & Johnson vaccine on Thursday, a welcome boost to the country’s stop-start inoculation campaign.
The decision paves the way for the distribution of 31 million doses, which the South African government has already secured, President Cyril Ramaphosa said this week.
The approval is based on a “rolling submission” of data on the vaccine’s performance from Dec. 11 to March 17, the South African Health Products Regulatory Authority said in a statement. The single-dose vaccine has been administered to over 269,000 health workers since February as part of the implementation phase of Johnson & Johnson’s trial in South Africa.
The South African authorities turned to the Johnson & Johnson vaccine after the country halted plans to roll out the AstraZeneca-Oxford vaccine, of which it had already acquired a million doses. In February, evidence emerged that the vaccine did not protect clinical-trial participants from mild or moderate illness caused by the more contagious virus variant that was first seen in the country. On Friday, the South African health minister, Dr. Zweli Mkhize, announced that the government had sold the AstraZeneca doses to the African Union, which will distribute them among 18 countries, including Liberia, Nigeria, and Zimbabwe.
The Johnson & Johnson vaccine showed a 64 percent efficacy rate in South Africa, where the variant known as B.1.351 has fueled a wave of infections that saw the country’s death toll rise to nearly 53,000, with over 1.5 million cases. The February results were an improvement of seven percentage points high than earlier data from South Africa released by the company.
The shots will be manufactured by the pharmaceutical company Aspen Pharma as part of a deal that will see 220 million doses produced in the coastal South African city of Gqeberha (formerly known as Port Elizabeth) and supplied to the rest of Africa via the African Vaccine Acquisition Trust, an African Union organization. The organization will also have the option to order an additional 180 million doses for a combined total of up to 400 million doses through 2022.
In February, Mr. Ramaphosa announced that his government had also secured 20 million doses of the Pfizer-BioNTech vaccine. With formal approval still underway, the health products regulator granted emergency use of the vaccine on a case-by-case basis.
South Africans have expressed increased frustration with the slow rollout of the Covid-19 vaccine, their anxieties heightened by fears of a third wave of infections as fall temperatures cool amid increased travel and mass religious gatherings over the Easter period.
San Marino, a tiny, independent republic within northern Italy, is perhaps best known — to the extent it is known at all — as one of the smallest countries on earth.
But the pandemic has given it a new, tragic distinction: a place with one of the world’s highest death rates from the coronavirus.
Just six weeks ago, San Marino risked becoming the last country in Europe to start inoculating its people. It had counted on an agreement with Italy to furnish it with vaccines, but they never materialized. With tensions rising and doctors threatening to stop working, the desperate government turned to Russia and found a warm embrace.
San Marino has long had close ties to Russia, and readily accepted more than 7,000 doses of the Sputnik V vaccine, which has not been authorized by European or Italian drug regulators.
Russians have been drawn for years to this nation of just 33,000 people, often flying directly from Moscow to the Italian beach town of Rimini only 10 miles away. More than 100,000 Russian tourists visit San Marino in a typical year.
Roberto Ciavatta, San Marino’s health minister, said that for his nation, the issue was not geopolitics but something simpler.
“The only vaccine in that moment available on the market was Sputnik,” he said.
Just as San Marino is within Italy but not part of it, it is ensconced in the heart of the European Union but not a member of the club or its vaccine-buying program. As Europe’s vaccination efforts stumbled, San Marino risked falling ever farther behind.
The positions are now reversed. San Marino has given at least one vaccine shot to 26 percent of its people, more than double the E.U. average. Officials say hundreds of Italians have tried to make vaccination appointments here, and some even showed up, hoping in vain to get vaccinated by the foreign state next door.
“We asked Italy for help and didn’t get any,” Denisa Grassi, a 42-year-old teacher, said after receiving her shot. “Now it’s the Italians who ask us.”
As states ramp up vaccinations and expand eligibility, health officials can look to one state in particular to better understand the challenges ahead: Maryland has encountered nearly all the geographic, demographic and human behavioral challenges that come with a public health task of this scale.
It has poor urban neighborhoods where many people lack access to regular care; wealthy Washington suburbs whose residents have proved adept at vacuuming up shots meant for other ZIP codes; isolated rural areas; and a sign-up system that has turned vaccine hunting into a part-time job for many.
“We are going to push, but we’re also going to have to pull,” said Dennis Schrader, the acting health secretary in Maryland, describing the state’s plan not only to increase capacity at mega-sites and pharmacies, but also to “pull people in” with smaller, more targeted efforts.
This week, Gov. Larry Hogan, a Republican, announced that all Maryland adults age 16 and older would be eligible for the vaccine by April 27.
While Mr. Hogan has faced criticism from local leaders about the pace of the state’s vaccination effort, some people now worry it is speeding up too quickly. Mr. Hogan has already been criticized for not doing enough to reach Black and Latino residents, who make up more than 40 percent of the state’s population, but only 28 percent of those who have received at least one shot.
The Hogan administration is planning to open four more mass vaccination sites by the end of April, bringing the total to 12. Mr. Hogan’s aim is to have 100,000 shots administered per day by May, up from an average of 57,000 now.
The state has started adding primary care doctors to the effort. It is also working with local health departments and community partners, particularly churches, to open “pop-up” vaccination sites aimed at populations that may be geographically or socially isolated, or distrustful of government.
Pastor John Jenkins at the First Baptist Church of Glenarden said he understood the role his church could play in Prince George’s County — a majority-Black area that has had high Covid infection rates, but low vaccine rates.
With the help of the University of Maryland Capital Region Health, he quickly created pop-up vaccine sites with his army of church volunteers.
The site at his church planned to vaccinate a few hundred people a day, but quickly got closer to 1,000 with residents like Denise Evans, who said she felt “more comfortable” getting her shot there. The church will soon ramp up to provide shots daily.
They opened the gates on Thursday, six months after the end of a brief and surreal regular season played before cardboard cutouts and empty stands. Opening day for 2021 brought none of the usual standing-room-only crowds; with limited capacities, the games looked more like sleepy gatherings in mid-April. But the buzz was authentic, and there’s nothing like the real thing.
The first home run of the new year sliced through swirling snow flurries in Detroit. It was so confusing that the hitter, Miguel Cabrera — who is quite familiar with home runs, having swatted 488 in his career — slid into second on his trip around the bases, thinking he had hit a double.
A few players wore masks on the field, like the Brewers’ Lorenzo Cain, who opted out of last season after a few games, and the Philadelphia Phillies’ Didi Gregorius, who has a chronic kidney disorder. Cain scored the winning run in the 10th inning for Milwaukee, and Gregorius drew an intentional walk in the 10th for the Phillies, setting up Jean Segura’s game-winning single and bringing joy to the 8,529 real, live people on hand.
“So much better, so much better — that’s how it should be,” Phillies starter Aaron Nola said. “Hopefully it’ll be more soon, but it was good to hear humans in the stands.”
With more than 34,000 seats empty, though, there were ever-present reminders of the pandemic, like static intruding on a clear signal.
Most sobering was the postponement of the Nationals’ opener, against the Mets in Washington, after a Nationals player tested positive for the coronavirus. Because several teammates and a staff member were found to have been in close contact with the player, Major League Baseball said the teams would not open on Friday, either.
Then again, even without the virus-related postponement, Thursday was bound to be less than complete. The reason was the most mundane, and perhaps the most predictable, of all: bad weather in the Northeast.
With rain forecast, the Boston Red Sox announced at 9 a.m. that they had called off their opener with the Baltimore Orioles. The teams will try again on Friday afternoon, weather — and coronavirus test results — permitting.
Declines in coronavirus testing in many states in the South and the Great Plains are making it harder to know just how widely the virus may be spreading in those states, even as restrictions are lifted and residents ease back into daily life, experts say.
States in both regions are reporting few new cases relative to their population, compared with harder-hit states like Michigan or New York. But they are also testing far fewer people.
Kansas, for example, is now testing about 60 people a day for every 100,000 in population, according to data compiled by Johns Hopkins University, and Alabama only a bit more. The picture is similar in Iowa, Mississippi and elsewhere.
By contrast, New York is averaging 1,200 tests a day per 100,000, and Rhode Island 1,677 per 100,000.
Testing has been falling in Kansas since Jan. 1, even though hospitalizations were at their highest level of the pandemic then, according to Tami Gurley, co-chair of the virus task force at the University of Kansas Medical Center. The state is now doing fewer tests relative to its population than any state except Idaho.
The tests they are doing in these low-rate states are finding virus.
Twelve percent of Kansas’ coronavirus tests are coming back positive. Alabama’s positivity rate is 12.8 percent. The rate in Idaho is 27.3 percent, the highest in the country. In New York, it’s just 3.5 percent.
So in the states that are doing relatively little testing, it’s possible that their daily case counts are low in part because asymptomatic or mild-symptom cases are going undetected.
Dr. Gurley says she is closely following hospitalizations, as a better indicator of the spread of the virus than new-case reports.
“We think that people are more focused on getting vaccines than getting tested,” she said. “It certainly makes it harder to figure out where we are going. We feel like we are at the point of another uptick in cases.”
Many states in the South and Midwest have relaxed their restrictions, including mask mandates, even though the national data signals that another surge in cases may be coming, according to Edward Trapido, an epidemiologist and associate dean for research at the Louisiana State University School of Public Health.
And many states are shifting resources away from testing to bolster vaccination efforts and meet President Biden’s goal of making all adult Americans eligible for a shot by May 1.
As a result, Dr. Trapido said, in many places these days, only the sickest patients are seeking out a coronavirus test.
“As vaccines have become widespread, people are becoming comfortable about not being tested,” he said. “There is a natural experiment going on. It’s a battle between getting people vaccinated and keeping the percent positive low. When I see a slight change in the curve upward, I get alarmed.”
Dr. Gurley said the shift in emphasis away from testing and toward vaccination may stem in part from widespread public fatigue with pandemic precautions and the political imperative in many states to reopen swiftly.
If all you want to do is prevent deaths from the virus, that may make sense, she said, but “if your end goal is to prevent spread, then we need more testing.”