Amid spiking cases, Europe is scrambling to contain the virus. Close to 1 million people have died of the virus around the world, a staggering toll.

The Centers for Disease Control and Prevention quietly introduced, and then just as quietly withdrew, a new document saying that the coronavirus is transmitted mainly by air.

The Centers for Disease Control and Prevention quietly introduced — and then on Monday quietly withdrew — guidance on its website acknowledging that the coronavirus is transmitted mainly through the air.

The rapid reversal is another in a string of confusing missteps from the agency regarding official guidance that it posts on its website. The latest debacle concerns the spread of the virus by aerosols, tiny particles containing the virus that can stay aloft for long periods and travel further than six feet.

Aerosol experts noticed on Sunday that the agency had updated its description of how the virus spreads to say that the pathogen is spread primarily by air.

The virus is spread through “respiratory droplets or small particles, such as those in aerosols, produced when an infected person coughs, sneezes, sings, talks, or breathes,” the C.D.C. said in its guidance posted Friday. These particles can be inhaled and seed an infection, the agency added: “This is thought to be the main way the virus spreads.”

“A draft version of proposed changes to these recommendations was posted in error to the agency’s official website,” the agency said, and that a once the final version is complete, “the update language will be posted.”

The document was posted to the C.D.C.’s website “prematurely” and is still being revised, according to a federal official familiar with the matter.

More than 200 experts in aerosol transmission appealed to the World Health Organization in July to review the evidence on aerosol transmission of the coronavirus. The W.H.O. acknowledged that this route appears to contribute significantly to the spread of the pandemic, but health experts disagree as to its importance relative to the heavier respiratory droplets that are sneezed or coughed by infected patients.

“In the scientific community, it’s become very clear that aerosols are very important,” said Linsey Marr, an expert in airborne viruses at Virginia Tech. “I hope that it comes back in some form that acknowledges the importance of aerosols.”

In another change of guidance on its website, the C.D.C. said in August that people who have close contact with an infected person but do not have symptoms don’t need to get tested. But last week, after The New York Times reported that the guidance was dictated by political appointees in the administration rather than by scientists, the agency reversed its position and said all close contacts of infected people should be tested regardless of symptoms.

Much of Europe is scrambling to avoid another round of economically devastating widespread lockdowns as new spikes emerge in France, hospitals begin to fill in Spain and officials in the United Kingdom warn that a six-month fight to contain the virus remains ahead.

New targeted lockdown measures took effect in Madrid on Monday, restricting nearly a million residents from traveling outside of their neighborhoods except for essential activities like work, school or emergency medical care.

The rules — which some residents protested over the weekend — come amid a spike in cases around the country, but concentrated in Madrid, where virus-related hospitalizations have tripled. New cases in Spain have risen to more than 10,000 per day on average over the past week, exceeding the official tally in the spring, when Spain was one of the worst-hit nations in Europe. Testing is more widely available now.

Though deaths countrywide have not risen to the levels seen earlier this year, the authorities in Madrid said on Sunday that 37 people there had died of Covid-19 in the past 24 hours, and about 4,000 patients were hospitalized, including some 300 in intensive care. The authorities there were preparing to reopen field hospitals if necessary.

In Britain, top scientific and medical advisers warned on Monday that infections could reach 50,000 a day by next month and prompt a significant new spike in fatalities, as Wales announced an expansion of lockdown orders to take effect on Tuesday.

“We have, in a bad sense, literally turned the corner,” said Chris Whitty, England’s chief medical officer, in a rare televised statement alongside Patrick Vallance, the chief scientific adviser.

They cautioned that Britain faces a six-month battle to control the virus. Britain has imposed fines of at least 1,000 pounds, about $1,300, on those who do not self-isolate after testing positive or being exposed to the virus. The fines, which begin on Sept. 28, can increase to a maximum of £10,000 for repeat offenders or for the most serious breaches.

The British government is debating imposing additional restrictions as it heads into the fall facing what Prime Minister Boris Johnson has already described as a “second wave.” Mr. Johnson is expected to speak about the virus situation on Tuesday.

Though Britain has fewer cases or fatalities than some European countries, like France and Spain, the fear is that it is following the same trajectory, with cases rising sharply as children return to school, students to colleges and workers to offices.

Italy’s health minister, Roberto Speranza, announced Monday that the country would mandate virus testing for people traveling from Paris and other parts of France where the virus is “significantly circulating.” Other areas include Nouvelle Aquitaine, Occitanie and Provence-Cote d’Azur. Last week the French health minister announced lockdowns in cities including Lyon and Nice.

Since Aug. 12, testing has been mandatory for anyone arriving in Italy who has visited Greece, Croatia, Spain or Malta in the two weeks prior. The policy will take effect Tuesday.

It is a staggering toll, almost 200,000 people dead from the coronavirus in the United States, and close to one million people around the world.

And the pandemic, which sent cases spiking skyward in many countries and then trending downward after lockdowns, has reached a precarious point. Will countries like the United States see the virus continue to slow? Or is a new surge on the way?

“What will happen, nobody knows,” said Catherine Troisi, an infectious disease epidemiologist at The University of Texas Health Science Center at Houston. “This virus has surprised us on many fronts, and we may be surprised again.”

In the United States, fewer new cases have been detected week by week since late July, after outbreaks first in the Northeast and then in the South and the West.

But in recent days, the nation’s daily count of new cases is climbing again, fueling worries of a resurgence of the virus as universities and schools reopen and as colder weather pushes people indoors.

In India, more than 90,000 new cases are now being detected daily, sending the country’s total cases soaring past five million.

In Europe, after lockdowns helped smother the crisis in the spring, the virus once again is burning its way across the continent.

Israel, with nearly 1,200 deaths attributed to the virus, imposed a second lockdown last week, one of the few nations to do so.

When the first wave of infections spread around the world, governments imposed sweeping restrictions: More than four billion people were under some sort of stay-at-home order at one point. Now, many countries are desperately trying to avoid such intense measures.

“We have a very serious situation unfolding before us,” Hans Kluge, the World Health Organization’s regional director for Europe, said last week. “Weekly cases have now exceeded those reported when the pandemic first peaked in Europe in March.”

Deaths in the United States from the virus neared 200,000 as of Monday morning. It was only four months ago, in late May, that the nation’s death roll reached 100,000. Even the current tally may be a significant undercount of the toll, analyses suggest.

Dr. Tom Inglesby, the director of the Center for Health Security at the Johns Hopkins Bloomberg School of Public Health, said it was conceivable that the death toll in the United States could reach 300,000 if the public lets down its guard.

“There are many countries we might consider our economic peers, or that are far less developed in terms of economy or health care systems, that are having far less mortality,” he said.

New York City’s roughly 1,400 school buildings have sat largely empty for six months, since its school system, the nation’s largest, abruptly closed classrooms in mid-March.

On Monday, for the first time since then, schools reopened for up to 90,000 pre-K students and children with advanced disabilities. The rest of the city’s 1.1 million students will start the school year online and will have the option of returning to classrooms over the next few weeks.

Though Monday’s reopening falls far short of what Mayor Bill de Blasio originally promised — all students having the option to return to classrooms — it is still a milestone in New York’s long path to fully reopening. New York is one of the few cities in the country where some children are back in classrooms.

The start of the school year in the city is still freighted with anxiety and unknowns, starting with the fact that nobody was quite sure how many students will show up to buildings today. Elementary school students will start in-person classes on Sept. 29, and middle and high school children can return on Oct. 1

Some kindergarten students who reported to their schools on Monday morning were sent away and told their return to classrooms would not be until later in the month.

At Public School 149 in Brooklyn, five students were turned away at the door since they were not in pre-K.

Balayet Hossain, the father of a kindergartner and a first-grade student at P.S. 149, said he received an email on Sunday from a teacher at the school that said, “I can’t wait to see you all tomorrow!”

Over the summer, New York City seemed poised to become the only big school district in America to offer in-person classes at the start of its school year. Despite recent stumbles, New York will have more students back in classrooms this month than any of the nation’s 10 largest school systems — if all goes according to plan.

An organization of Black doctors is forming a task force to screen federal decisions about coronavirus vaccines and treatments, the latest sign of the medical community’s eroding trust in the Food and Drug Administration and the Centers for Disease Control and Prevention under President Trump.

The panel is being set up by the National Medical Association, which was founded in 1895 when Black doctors were being excluded from other professional medical societies, STAT News reported on Monday.

Nonwhite communities have suffered disproportionately more from the virus, as hospitalization and death rates have been higher, particularly in Black communities.

“It’s necessary to provide a trusted messenger of vetted information to the African-American community,” Dr. Leon McDougle, the association’s president, told STAT news.

Dr. McDougle cited the Trump administration’s push to approve the malaria drug hydroxychloroquine as a treatment for Covid-19. The F.D.A. gave the drug an emergency use authorization in March, but revoked it in June when studies found significant risks and no benefit to Covid-19 patients.

Many experts are worried that the push to deliver a vaccine on a short timeline will yield an inoculation that has not been rigorously screened and tested, Dr. McDougle told STAT News, and that could lead Black people — who have long been underrepresented in drug trials — to believe that a vaccine endorsed by the government may still not be safe.

The foundations of trust between Black Americans and the medical establishment have been shaken over the years by unequal and sometimes unethical treatment, and especially by an infamous 40-year research study known as the Tuskegee experiment, in which Black men were infected with syphilis by federal health officials and then were deliberately left untreated while researchers observed the course of the disease. The experiment ended in 1972.

Cuba, a police state with a strong public health care system, was able to quickly control the coronavirus, even as the pandemic threw wealthier nations into crisis. But its economy, already hurting from crippling U.S. sanctions and mismanagement, was particularly vulnerable to the economic devastation that followed.

As nations closed airports and locked down borders to combat the spread of the virus, tourist travel to Cuba plummeted and the island lost an important source of hard currency, plunging it into one of the worst food shortages in nearly 25 years.

What food is available is often found only in government-run stores that are stocked with imports and charge in dollars. The strategy, also used in the 1990s, during the economic depression known as the “special period,” is used by the government to gather hard currency from Cubans who have savings or get money from friends or relatives abroad.

Even in these stores, goods are scarce and prices can be exorbitant: One shopper recently couldn’t find chicken or cooking oil, but there was a 17-pound ham going for $230 and a seven-pound block of manchego cheese with a $149 price tag.

And the reliance on dollar stores, a move intended to prop up the socialist revolution in a country that prides itself on egalitarianism, has exacerbated economic inequality, some Cubans say.

“This is a store that charges in a currency Cubans do not earn,” said Lazaro Manuel Domínguez Hernández, 31, a doctor who gets cash from a friend in the United States to spend at one of the 72 new dollar stores. “It kind of marks the difference in classes, because not everyone can buy here.”

Cuba’s economy was struggling before the coronavirus. The Trump administration has worked hard to strengthen the decades-old trade embargo, going after Cuba’s sources of currency. It also imposed sanctions on tanker companies that delivered petroleum to Cuba from Venezuela and cut back on the commercial flights from the United States to the island.

Cuba is facing “the triple threat of Trump, Venezuela and then Covid,” said Ted A. Henken, a professor at Baruch College and an author of the book “Entrepreneurial Cuba.” “Covid was the thing that pushed them over the edge.”

From resistance to face masks and scorn for the science of the virus to predicting the imminent arrival of a vaccine while downplaying the death count, President Trump and a sizable number of his supporters have aligned behind an alternate reality minimizing a tragedy that has killed an overwhelming number of Americans and gutted the economy.

This mix of denial and defiance runs contrary to the overwhelming evidence about the spread and toll of the virus, and it is at the center of Mr. Trump’s re-election effort as early voting begins in Minnesota, Virginia and other states.

To some extent, this viewpoint reflects the resentments of Americans living in regions of the country, like upstate New York and the upper reaches of Michigan, that have been relatively untouched by the virus but have had to endure drastic business shutdown measures.

“The people who need to shelter in place should do so, but I do not feel that that should ruin the economy,” said Karla Mueller, a Republican and church custodian who lives in Fond du Lac, Wis. “I think it’s ruined a lot of people’s small businesses. I just don’t feel that that’s necessary.”

But it is also a direct result of the look-the-other-way message that the Trump administration has sent with increasing urgency, pollsters and strategists say, as the president faces a strong challenge to re-election from Joseph R. Biden Jr., his Democratic opponent. Mr. Trump has called on Twitter for people to “LIBERATE” states that have imposed stay-at-home orders, threatened to withhold aid from Democratic governors and undercut medical professionals who have cautioned against the use of unproven medical treatments and premature school reopenings.

The president’s critics say his confrontational approach has kept the country from forming a consensus about how to fight the worst public health crisis in more than 100 years.

“The emotion, the passion — it’s out of hand,” said Representative Debbie Dingell, Democrat of Michigan, who pointed to two violent episodes in her state that stemmed from disagreements over wearing masks. “People have been shot and killed. A security guard in a dollar store. There was another fight at Walmart. This is insane.”

Polls show that Republicans approve of how Mr. Trump has handled the response to the virus by overwhelming margins and — unlike much of the country — think the United States has moved too slowly to reopen. A majority of them also support wearing masks, though not by the same margin as Democrats or the nation at large.

Virus restrictions on travel and gatherings will be lifted across most of New Zealand starting at midnight on Monday, Prime Minister Jacinda Ardern said.

However, in Auckland, the country’s largest city, restrictions are still in place and will be eased but not entirely lifted at midnight on Wednesday. The city was the center of a mysterious outbreak in August that prompted Ms. Ardern to again place the city under lockdown.

Starting Thursday, Auckland residents will be able to gather in groups of up to 100 but will be required to stay home if they are sick and log their contacts and movements. Face coverings will still be compulsory on public transportation and are encouraged elsewhere in public.

“Some may query the cautious approach we are taking,” Ms. Ardern told reporters at a news conference on Monday, adding that a Health Department analysis suggested that the country had a 50 percent chance of eliminating new infections by the end of September. “That is cause for us not to get ahead of ourselves and remain vigilant,” Ms. Ardern said.

New Zealand, an island nation of five million people, has been lauded for its pandemic response. It has reported just over 1,800 cases of the coronavirus and 25 deaths, according to a New York Times database.

The guidelines announced Monday will be reviewed again in two weeks, Ms. Ardern said, and restrictions could possibly be lifted further.

The state of Victoria in Australia, which has been under strict lockdown for several weeks, recorded 11 cases overnight, its lowest daily rise in infections in three months, the authorities said on Monday. Two deaths were also recorded. Despite the low numbers, Melbourne, the country’s second most-populous city, remains under curfew, while lesser restrictions remain in place across the rest of the state.

The Taj Mahal, one of India’s most famous landmarks and a huge tourist draw, reopened on Monday after being closed for more than six months as part of efforts to curb the spread of the virus. The monument, which receives a rough average of 20,000 visitors daily, will restrict admittance to 5,000 people a day. The site reopened despite India having more than 5.4 million cases, and daily case counts of more than 90,000, the second-highest caseload behind the United States.

The German city of Munich will require masks in some of its open-air spaces, including busy streets and popular squares, starting Thursday, the mayor announced on Monday. Though masks are required when shopping, on public transportation or other indoor spaces in most of Germany, public outdoor spaces have avoided the kind of mask rules in place in other European cities. The authorities in Munich, which is experiencing an increasing number of infections, also limited gatherings to no more than five people or members of two households. The city had already canceled the traditional Oktoberfest.

People in some of the world’s most vulnerable communities have been left close to economic catastrophe by measures taken to stop the spread of the coronavirus, according to a new report.

Economies around the world have been decimated by the pandemic, but for people in Afghanistan, Iraq, Kenya, Venezuela and 10 other countries included in the report from the Norwegian Refugee Council, the financial crises have exacerbated the challenges they were already facing.

In countries where conflict and displacement are commonplace, many are experiencing hunger, homelessness and a crisis in education amplified as a result of lost work, income and increased debt.

With businesses and markets closed and travel restricted, nearly 80 percent of people in already precarious situations have seen their incomes drop because of lost jobs. Without the means to pay rent, many have been evicted or forced from their homes, according to the report. With so few resources, people said they were less likely to send their children to school and had been unable to afford medical treatment or even the most basic food products.

“The world’s most vulnerable communities are in a dangerous downward spiral,” Jan Egeland, the secretary general of the Norwegian Refugee Council warned.

Hunger is increasing around the world and the United Nations World Food Program expects the number of people confronting potentially life-threatening levels of so-called food insecurity in the developing world to nearly double this year to 265 million. Seventy percent of survey respondents said they had cut the number of meals for their households since the pandemic began.

Women and girls in vulnerable communities have been most affected by the economic crisis, the report said. Not only have they lost jobs and shouldered the burden of unpaid care, but like many across the world, the financial constraints have led to an increase in domestic violence.

Reporting was contributed by Livia Albeck-Ripka, Stephen Castle, Manny Fernandez, Apoorva Mandavilli, Raphael Minder, Adam Nagourney, Jeremy W. Peters, Simon Romero, Marc Santora, Anna Schaverien, Christopher F. Schuetze, Eliza Shapiro, Eileen Sullivan, Sameer Yasir and Karen Zraick.


News – Covid-19 Live Updates: In Another Reversal, C.D.C. Removes Guidance on How the Virus Is Transmitted