Covid-19 Live Updates: Drugmaker Has Begun Final Tests of a One-Shot Vaccine

Johnson & Johnson begins the final stage of clinical trials for its vaccine.

Buoyed by positive results in its earlier studies, Johnson & Johnson has begun the final stage of clinical trials for its coronavirus vaccine.

Although they started a couple of months behind the other so-called Phase 3 trials in the United States, Johnson & Johnson’s trials, which began on Monday, will be the largest, with plans to enroll 60,000 participants. And this experimental vaccine may have considerable advantages over some of its competitors, experts said. It does not need to be stored in subzero temperatures, and may require just one dose instead of two.

“It would be fabulous if we had something at a single dose,” said Dr. Judith Feinberg, the vice chairwoman for research in medicine at West Virginia University, who was not involved in the study.

Only Phase 3 trials, which compare the effects of a vaccine with those of a placebo, can determine if a single dose is indeed effective, Dr. Feinberg said. If it works, that could greatly speed efforts to curb the pandemic.

“The real issue here is time,” she said. “We’ve got to vaccinate a lot of people really quickly.”

At a news conference on Tuesday, Dr. Paul Stoffels, chief scientific officer of Johnson & Johnson, said the company might be able to determine by the end of the year if the vaccine is safe and effective. The company will soon be posting a manuscript online with data from the earlier phases of its trials, he said.

“Big news. Numerous great companies are seeing fantastic results. @FDA must move quickly!” President Trump said in a Twitter post Wednesday morning.

Mr. Trump’s enthusiasm and push for a vaccine has raised concerns among health experts that he will try to interfere with a testing and review process that was designed to be thorough to ensure a potential vaccine is both effective and safe.

Johnson & Johnson’s experimental vaccine uses an adenovirus to carry a gene from the coronavirus into human cells. The cell then produces coronavirus proteins, which can potentially prime the immune system to fight off a later infection by the virus.

Adenovirus vaccines must be kept refrigerated but not frozen, unlike the two front-runner vaccines, by Moderna and Pfizer, which depend on bits of genetic material known as mRNA. The freezing requirement could make the distribution of those vaccines difficult, especially to places without advanced medical facilities. Moderna and Pfizer’s vaccines also require two jabs given a few weeks apart, a significant logistical hurdle.

“I mean, just think about yourself — how much easier would it be for you to go to your local doctor or your local drugstore, and be once and done?” said Dr. Daniel Barouch, a virologist at Boston’s Beth Israel Deaconess Medical Center who helped develop the Johnson & Johnson vaccine.

With the independence of public health agencies under scrutiny, U.S. virus experts are set to testify in the Senate.

Four of the top doctors leading the government’s virus response are scheduled to testify in the Senate on Wednesday amid growing questions about the Trump administration’s efforts to bend scientific decision-making to the president’s advantage.

With the number of virus deaths in the United States having surpassed 200,000 on Tuesday, the Senate will get a report on the state of the government’s response from Dr. Anthony S. Fauci, the government’s leading infectious disease expert; Dr. Robert R. Redfield, the director of the Centers for Disease Control and Prevention; Dr. Stephen M. Hahn, the commissioner of the Food and Drug Administration; and Adm. Brett P. Giroir, the testing czar.

Looming over the hearing will be the threat of a public scolding by Mr. Trump if he hears testimony he doesn’t like. Last week the president rebuked Dr. Redfield after he told a Senate committee that a vaccine would not be widely available until the middle of next year and that masks were so vital in fighting the disease caused by the coronavirus, Covid-19, that they may be even more important than a vaccine.

The hearing before the Senate Health, Education, Labor and Pensions Committee, which is scheduled to begin at 10 a.m. Eastern, follows upheaval within the federal Department of Heath and Human Services, whose top spokesman, Michael R. Caputo, took medical leave last week after delivering an outlandish rant on Facebook Live in which he accused C.D.C. scientists of sedition, promoted conspiracy theories and warned of armed revolt.

The Facebook appearance came after the revelation that Mr. Caputo’s science adviser, Dr. Paul Alexander, had tried to pressure the agency to revise or delay its weekly scientific reports. Dr. Alexander has since left the department. Democrats will almost certainly use the hearing to question Dr. Redfield about those events.

Dr. Redfield will likely also face questions about guidelines for testing issued last month that suggested certain people exposed to the virus did not need to be screened. Internal documents show the guidance had been posted on the C.D.C.’s website despite serious objections from agency scientists, and the agency reversed it last week.

Lawmakers are likely to question Dr. Hahn about the F.D.A.’s plan to issue stricter guidelines for the emergency authorization of any new coronavirus vaccine, which would add a new layer of caution to the vetting process as Mr. Trump has insisted a vaccine will be ready as early as next month. The guidelines may be formally released as early as this week if approved by the White House, and would recommend that clinical trial data be vetted by a committee of independent experts before the F.D.A. takes action, according to several people familiar with the draft.

On Tuesday, Dr. Fauci said he worried about the country entering the cooler months without having a handle on the virus. The United States is seeing an average of about 40,000 new cases a day based on a seven-day average, according to a New York Times database.

“Those are the things that I get concerned about as we get into October and November and December,” Dr. Fauci said Tuesday on CNN. “I’d like to see us go into that at such a low level that when you have the inevitable cases you can handle them.”

global roundup

Plastic face shields do little to reduce the spread of the virus, research suggests.

Plastic face shields do little to contain the spread of microscopic airborne particles created by such activities as talking, singing or sneezing, according to recent research from Japan that modeled the diffusion of respiratory aerosols on the world’s fastest supercomputer.

The shields, which have been marketed as an alternative to face masks to guard against the coronavirus, do almost nothing to stop the spread of microscopic airborne droplets that are increasingly understood to be a major vector for spreading the disease, according to a recent study by researchers at the Riken Center for Computational Science, a research institute based in Kobe, Japan.

Face shields may be useful for protecting the wearer from the droplets generated by others, but are almost completely ineffective at protecting others from the wearer’s own droplets, according to Makoto Tsubokura, a professor at Kobe University and the lead researcher on a team that is using Japan’s world-beating supercomputer to better understand how to defend against the coronavirus.

While the face shields can block the spread of some large droplets, they are essentially incapable of capturing droplets five microns or smaller, according to simulations run by researchers on Fugaku, the Japanese supercomputer currently considered the world’s fastest.

Japan was one of the first countries to understand that tiny airborne particles were one of the most likely methods of transmission for the virus, which has killed nearly one million people worldwide, according to a New York Times database. The country promoted face masks as the first line of defense against the virus.

Since the pandemic’s early days, health experts in Japan have cautioned people to avoid conditions known as the three C’s — closed spaces, crowded places and close contact — thought to increase the risk of exposure to an airborne dose of the disease.

The simulation conducted by researchers at Riken demonstrated that face masks — whether manufactured or handmade — are far more effective at blocking the diffusion of airborne droplets than face shields.

In other news around the world:

• Mr. Trump criticized China as the coronavirus villain on Tuesday in a strongly worded United Nations speech, extolling his own actions in the pandemic and demanding that the global organization hold accountable “the nation which unleashed this plague onto the world.” China’s leader, Xi Jinping, clearly anticipating Mr. Trump’s attacks, portrayed the virus as everyone’s challenge and described China’s response as scientific, generous and responsible. “Any attempt at politicizing or stigmatizing this issue must be rejected,” Mr. Xi said.

• China is making it easier for mainland tourists to visit Macau, the world’s gambling capital. Starting Wednesday, visitors will be allowed to enter semiautonomous territory without undergoing a 14-day quarantine, the Chinese authorities said, as long as they present a test taken within the previous seven days showing that they are free of the coronavirus. Macau, which has suffered a steep economic downturn during the pandemic, has recorded a total of 46 cases of the coronavirus. Macau’s gross gaming revenue totaled $ 36.5 billion last year, about six times that of the Las Vegas Strip.

• Foreigners with valid residence permits for work, personal matters and family reunions in China will be allowed to enter the country again without having to apply for new visas starting next week, the Chinese Foreign Ministry said Wednesday. Such foreign nationals have been barred since March.

• Saudi Arabia has said it would allow up to 6,000 Saudi citizens and residents a day to visit Mecca’s Grand Mosque beginning Oct. 4, according to The Associated Press. The quota is set to rise later in the month, The A.P. said Tuesday, and the government said that Muslim travelers from outside the country — who have been barred from making the annual pilgrimage to the holy city during the pandemic — could be allowed to do so starting in November.

• About 600 pubs that serve only drinks can reopen in Northern Ireland on Wednesday for the first time in six months. Pubs that serve food were allowed to reopen in July. But they may face new restrictions after Prime Minister Boris Johnson of Britain announced this week that pubs, bars and restaurants in England would be required to close by 10 p.m. starting Thursday. The same measure will be applied in Scotland starting Friday. Northern Ireland will decide whether to implement a curfew on drinks and hospitality venues on Thursday.

U.S. roundup

After months of devastation, small signs of renewal highlight the grit of New Yorkers who stuck with the city.

In March, New York City became the epicenter of the virus in the United States. Months of hardship and numbness followed: Nearly 24,000 people in the city have died as the pandemic preyed on its vulnerabilities.

But six months later, as the infection rate has dropped to only 1 percent, small transformations and vibrant signs of renewal have revealed the grit and gifts of those who stayed as others scurried to second homes.

The prospect of a second wave is frightening. And already, attempts at returning to offices, schools and sports have been problematic. Signs of real progress have been slow. And yes, many have left.

But in Central Park, weddings and birthday parties, once tucked away in rented halls, have spilled out into the open — the celebrations jubilant though everyone is wearing masks. A struggling Greek restaurateur in Queens has added ambience to curbside tables with lanterns and bouquets. Top designers like Christian Siriano and Naeem Khan have included mask-making in their repertoire.

In Brooklyn, a trio of D.J.s throw digital parties to raise money for the owners of dance lounges, while a coffee shop in Bedford-Stuyvesant stocks four community refrigerators with fresh fruits and vegetables for the hungry. And industrious entrepreneurs and street vendors have redesigned business plans to stay afloat.

“There are still these beautiful moments that you don’t have in any other place in the world, like walking in Prospect Park and stumbling upon a jazz concert or a brass band,” said Dominique Nisperos, 37, a comedian and sociologist from Bedford-Stuyvesant who spent two months recovering from Covid-19. “The lows of the pandemic have been really low, but what’s been my saving grace has been the people of New York.”

The sense of renewal comes as New York City’s Health Department warned on Tuesday that Covid-19 was spreading at increasing levels in several neighborhoods in Brooklyn and Queens, a worrisome indicator after a couple of months of declining or flat transmission.

City health officials said that they were especially concerned about a clear uptick in transmission among some of the city’s Hasidic communities, which were devastated by Covid-19 in the spring but had seen few cases in the summer.

In other news from around the United States:

• Students in Miami-Dade County, the fourth-largest school district in the country and the largest in Florida, will be able to choose to return to their classrooms next month under a plan approved by the school board after a marathon two-day meeting.

• New guidelines from the Centers for Disease Control and Prevention warned that traditional trick-or-treating this Halloween would carry more risk than other ways of celebrating the holiday. The guidelines were somewhat unexpected, given that scientists generally consider it safe to gather outdoors with masks on.

An English soccer team was found to have the virus after tests paid for by its opponent.

A professional soccer game in England was canceled on Tuesday after members of one of the teams were found to be infected with the coronavirus based on tests before the match that were paid for by the other team.

The game was the first significant casualty of the new English soccer season and raised concerns of more postponements amid an increase in the number of Covid-19 cases in Britain.

Leyton Orient, which plays in the lowest of England’s four professional divisions, had been scheduled to host Tottenham Hotspur, from the top-tier Premier League, in the Carabao Cup. The competition is open to the 92 teams across the various professional levels of English soccer that runs parallel to the regular season.

The game would have provided significant television income to Orient, which like other teams in the lower divisions of English soccer have been battered by the effects of the pandemic. Several teams have been forced to rely on emergency funding to make up for having to play without supporters, their biggest source of revenue.

The positive tests came after Tottenham paid for the Orient players to undergo tests before the game. The outcome raises concerns over the efficacy of the testing regime in English soccer divisions outside of the Premier League, which for financial reasons are not as stringent as they are in the top division, where tests are mandatory.

Orient’s most-recent opponents have been asked to take tests.

The decision to cancel the game was made after talks between the English Football League, the organization responsible for the competition, and local health authorities.

Orient now faces forfeiting the games because of rules for the competition devised in the aftermath of the pandemic that state that teams that cannot take to the field must register a loss.

“It is an incentive for people not to test, and that will only create a worse situation in the football world and the U.K.,” said Orient’s chairman, Nigel Travis.

The Vienna Opera Ball, one of Austria’s premier social events, has been canceled.

The 2021 Vienna Opera Ball, one of the most prestigious galas on Austria’s social calendar, has been canceled because of the pandemic, the country’s chancellor, Sebastian Kurz, announced on Tuesday.

The event, which had been scheduled for Feb. 11, is normally held in the main hall of the state opera house, built in 1869, which is converted to a ballroom. Attended by more than 5,000 guests, the ball involves two performances of Mozart’s “The Magic Flute.”

Tickets to the usually sold-out event cost between $ 370 to more than $ 27,000 dollars for a lodge.

The cancellation was announced five months in advance in part so that more pandemic-appropriate plans could be made. The opera is currently conducting regular performances under strict social-distancing rules.

Despite coming out of the first wave of coronavirus cases reasonably well in April and May, Austria is seeing a resurgence in infections. Last week, the country recorded 857 new infections in one day, a figure not seen since the very height of the pandemic at the end of March.

“We all hope that in February 2022 we will again be able to organize a brilliant opera ball,” Bogdan Roscic, the opera’s director, said in a statement.

Reporting was contributed by Ben Dooley, Rick Gladstone, Joseph Goldstein, Mike Ives, Corina Knoll, Sharon LaFraniere, Patricia Mazzei, Aimee Ortiz, Tariq Panja, Campbell Robertson, Anna Schaverien, Christopher F. Schuetze, Sheryl Gay Stolberg, Noah Weiland, Elaine Yu and Carl Zimmer.