The federal government is expected to take a significant step this week toward offering booster doses to a much wider range of Americans as advisers to the Food and Drug Administration meet on Thursday and Friday to discuss recipients of the Johnson & Johnson and Moderna coronavirus vaccines.
So far, regulators have authorized booster shots only for certain adults who received the Pfizer-BioNTech vaccine — a source of some frustration to the government’s medical advisers, who questioned at a meeting last month whether recipients of the other shots were being left out.
But the Biden administration is eager to shore up the protection provided by all three vaccines. And federal officials have become increasingly worried in particular about the more than 15 million Americans who received the Johnson & Johnson vaccine, which is less effective than the others.
On Thursday, the F.D.A.’s advisory panel of vaccine experts will discuss safety and efficacy data regarding booster shots for Moderna recipients. On Friday, the group will discuss Johnson & Johnson boosters. The agency typically issues decisions within a few days of advisory committee meetings.
The expert committee will also hear an eagerly awaited presentation on Friday from scientists at the National Institutes of Health on the effectiveness of mixing different brands of vaccines.
Dr. Peter Marks, the F.D.A.’s top vaccine regulator, suggested last week that federal officials favor extra shots for all three vaccines. “The data seem to demonstrate that booster shots seem necessary,” he said.
The deliberations come as coronavirus cases across the United States are falling, with the seven-day average of daily new cases slipping below 100,000 for the first time since early August. Hospitalizations and deaths are also declining.
Dr. Anthony S. Fauci, the nation’s top infectious disease doctor, said in a CNN interview on Sunday that “we have to be careful that we don’t prematurely declare victory,” citing the potential for the virus to rebound among unvaccinated Americans.
Dr. Fauci said that vaccinating younger children could offer another crucial line of defense. As early as Halloween, the F.D.A. could authorize the Pfizer-BioNTech vaccine for children ages 5 to 11, a move that could help protect more than 28 million people in the United States.
Although the federal government has emphasized for months that all three vaccines are highly effective, a recent study by the Centers for Disease Control and Prevention found that Johnson & Johnson’s single-dose vaccine was only 71 percent effective against hospitalization from Covid-19, compared with 88 percent for the two-dose Pfizer-BioNTech vaccine and 93 percent for Moderna’s two-shot regimen.
Last month, Johnson & Johnson announced that a second dose, given two months after the first, bolstered the vaccine’s effectiveness against symptomatic Covid-19 to 94 percent. The firm also said two shots were 100 percent effective against severe disease, although that estimate was less conclusive.
People eligible for Pfizer’s booster include those 65 and older and those who live in long-term care facilities, have underlying medical conditions or are at higher risk of exposure to the virus because of their jobs or institutional settings, a group that includes health care workers, teachers and prisoners.
The F.D.A. and C.D.C. are expected to propose essentially the same criteria for booster shots of Moderna and Johnson & Johnson, although they could also discuss whether to broaden eligibility to include more middle-aged people.
SYDNEY, Australia — With excitement and caution, Sydney stepped out of lockdown Monday after more than 100 days of Delta-diminished existence.
It was “Freedom Day,” with rules. Across the state of New South Wales, home to Sydney, as many as 10 vaccinated people could gather at home, with the number rising to 100 people for weddings, and 500 for outdoor events. Bars and restaurants also opened with masks required indoors when people are not eating and drinking.
But with more than 70 percent of the state’s adult population fully vaccinated, the first few sips of normalcy were more than enough to celebrate.
“People can call it whatever day they want to call it,” said Dominic Perrottet, the state premier, who accidentally sprayed himself with beer as he tapped a keg to commemorate the occasion. “I just think it’s a great day for the people of our state based on the efforts and sacrifices that everyone has made.”
For a country that was a capital of the “Covid zero” strategy to fully eliminate the virus, it’s been a wrenching metamorphosis. When the outbreak started in June, Australia lacked both urgency and supplies of the vaccine. New cases exploded to 1,500 a day. Now, after months of public compliance, case numbers have fallen to about 500 daily and many epidemiologists believe the country is on track to fully vaccinate 90 percent of its population if not more.
Given the promising numbers, Mr. Perrottet has been rapidly accelerating the move away from restrictions. He recently granted an exemption that will allow 10,000 vaccinated fans to attend Sydney’s The Everest horse race. He has also pushed to reopen international travel as early as next month.
The progress is still uneven. Some regional communities have much lower vaccination rates. Melbourne, Australia’s second-largest city, is still locked down, with case numbers hovering at around 1,500 per day. And in Western Australia, which has enjoyed life without Covid for most of the pandemic, only around half of adults are fully vaccinated, which means that Sydney residents may be able to reach New York before they can visit Perth because of state border restrictions.
But travel is only one of the joys that people are eager to experience. Salons have been popular — with some opening at 12:01 a.m., the moment they were allowed. Gyms also suddenly came back to life early Monday morning, and even the most mundane of activities seemed to be welcomed.
Alexis Phitidis, the owner of a mattress store in Eastern Sydney, sent text messages to suppliers and friends when there was just one minute to go until it reopened. Inside, a half-dozen customers lay on mattresses to test what they wanted to buy.
“It’s busy but calm,” Mr. Phitidis said. “People are just grateful for the opportunity — we’re all grateful for the opportunity to just engage.”
A customer suddenly rushed past. He offered three words that captured the mood: “It’s bloody awesome.”
Merck said on Monday that it had submitted an application to the Food and Drug Administration to authorize what would be the first antiviral pill to treat Covid.
An approval for the drug, molnupiravir, would be a milestone in the fight against the coronavirus, experts said, because a convenient, relatively inexpensive treatment could reach many more high-risk people sick with Covid than the cumbersome antibody treatments currently being used.
The Biden administration is preparing for an authorization that could come within weeks. If approved, the pill is likely to be allocated to states, as was the case with the vaccines. States could then distribute the pills how they wish, such as through pharmacies or doctors’ practices, senior administration officials said.
If the pill wins authorization, tens of millions of Americans will most likely be eligible to take it if they get sick with Covid — many more than the supply could cover, at least initially. The federal government has placed an advance order for enough pills for 1.7 million Americans, at a price of about $700 per patient. That is about one-third the price that the government is paying for the monoclonal antibody treatments, which are generally given via intravenous infusion.
Merck, which is developing the pill with Ridgeback Biotherapeutics of Miami, expects to be able to produce enough pills for 10 million people by the end of this year. Governments have raced to lock up supplies since the strong clinical trial results were released this month; Australia, Malaysia, Singapore and South Korea have all announced agreements.
An antiviral pill being developed by Pfizer and one from Atea Pharmaceuticals-Roche will report study results in the next months and, if effective, could expand supply.
Merck’s pill is meant to be taken at home as four capsules twice a day for five days, for a total of 40 pills. It halved hospitalizations and deaths in a clinical trial that enrolled unvaccinated adults who had begun showing Covid symptoms within the previous five days and were at high risk for bad outcomes from the disease.
Merck said it was seeking authorization for its pill to be given only to high-risk adults, which in the clinical trial was most commonly people over 60 or younger people with obesity, diabetes or heart disease.
It was not clear whether the treatment would be available to vaccinated people, who were not eligible for the clinical trial. A company spokeswoman said it would be up to the F.D.A. to decide.
Originally tested for influenza, the drug works by stopping the coronavirus from replicating by inserting errors into its genetic code.
That mechanism is likely to make one high-risk group, people who are pregnant, ineligible to receive the pills if they are authorized, because of fears that the drug might cause mutations that could result in birth defects. In the clinical trial, volunteers had to agree to abstain from unprotected sexual intercourse for four days after they finished taking the pills, and some women of childbearing age had to have a negative pregnancy test to enroll in the study.
Sheryl Gay Stolberg contributed reporting.