A second dose of Johnson & Johnson’s vaccine substantially increased its protection against Covid-19, the company announced Tuesday morning.
In a clinical trial, researchers found that two doses of the vaccine delivered 94 percent efficacy against mild to severe Covid-19 in the United States, up from 74 percent conferred with a single shot, the company reported. And two shots showed 100 percent efficacy against severe disease, although that estimate had a wide range of uncertainty.
The data, presented in a news release, has been submitted to the Food and Drug Administration, Johnson & Johnson said. Since the company received emergency authorization in February, 14.6 million people in the United States have received its one-shot vaccine.
On Friday, an F.D.A. advisory committee recommended that the agency authorize Pfizer-BioNTech booster shots for people who are at least 65 or at high risk of Covid. That vaccine, like Moderna’s, offers high levels of initial protection after two doses, which then seem to diminish slightly over several months.
By contrast, Johnson & Johnson’s vaccine has shown little sign of waning. Researchers released a study last week comparing 390,517 vaccinated people to 1,524,153 unvaccinated ones. Up to five months after vaccination, the effectiveness of the Johnson & Johnson vaccine against hospitalization remained steady at around 81 percent.
As the pandemic has unfolded, people who received the Johnson & Johnson vaccine have waited for guidance about whether they’ll need a booster. The new clinical trial, which recruited 32,000 volunteers around the world, compared people who received one dose of Johnson & Johnson to those who received two doses eight weeks apart.
The researchers found that the second shot lifted the level of antibodies in the blood of volunteers four times as high as the level produced by the first shot. That improvement translated into stronger protection.
Many people got their Johnson & Johnson shot far more than eight weeks ago. Other research suggests that the extra time between doses could mean even better protection.
In a separate study announced last month, Johnson & Johnson gave boosters to clinical trial volunteers six months after their first dose, and then measured their antibody levels.
Initially, the researchers reported that the antibodies rose nine times as high as after the first dose. But in Tuesday’s news release, the company announced the level had continued to rise, reaching 12 times as high as the initial levels.
Some preliminary studies suggest that higher levels of antibodies against the coronavirus produce higher levels of protection against Covid. If that’s true, then a second Johnson & Johnson shot given after a wait of several months may prove even more effective than after just eight weeks.
With Pfizer-BioNTech’s announcement on Monday that its coronavirus vaccine had been shown to be safe and effective in low doses in children ages 5 to 11, a question looms: How many parents will have it given to their children?
If authorized by the Food and Drug Administration, the vaccine could be a game changer for millions of American families and could help bolster the U.S. response to the highly contagious Delta variant. There are about 28 million children of ages 5 to 11 in the United States, far more than the 17 million of ages 12 to 15 who became eligible for Pfizer’s vaccine in May.
But it remains to be seen how much of the younger group will be vaccinated. Uptake among older children has lagged, and polling indicates reservations among a significant number of parents.
Lorena Tule-Romain was up early Monday morning, getting ready to ferry her 7-year-old son to school in Dallas, when she turned on the television and heard the news.
“I was like, ‘Oh my gosh, this is exciting,’” said Ms. Tule-Romain, 32, who said she felt a surge of hope and relief. She has spent months in limbo, declining birthday party invitations, holding off registering her son for orchestra in school and even canceling a trip to see her son’s grandparents in Atlanta.
Ms. Tule-Romain will be among those eagerly waiting to learn whether federal officials authorize the vaccine for the younger group, a step that is expected to come first on an emergency-use basis, perhaps as soon as around Halloween.
However the F.D.A. rules, Michelle Goebel, 36, of Carlsbad, Calif., said she was nowhere near ready to vaccinate her children, who are 8, 6 and 3, against Covid-19.
Though Ms. Goebel said she had been vaccinated herself, she expressed worry about the risks for her children, in part because of the relatively small size of children’s trials and the lack of long-term safety data so far. She said the potential risk from a new vaccine seemed to her to outweigh the benefit, because young children have been far less likely than adults to become seriously sick.
Only about 40 percent of children ages 12 to 15 have been fully vaccinated so far, compared with 66 percent of adults, according to federal data. Polling indicates that parental openness to vaccination decreases with a child’s age.
About 20 percent of parents of 12- to 17-year-olds said they definitely did not plan to get their child vaccinated, according to polling by the Kaiser Family Foundation published last month. The “definitely not” group grew to about 25 percent in parents of children ages 5 to 11, and 30 percent among parents of under-5s.
René LaBerge, 53, of Katy, Texas, said she planned to vaccinate her 11-year-old son when he became eligible. “But I’m not impatient. I want them to do the work,” she said.
She said she had heard about some rare, but serious, side effects in children, and she was eager for federal officials to thoroughly review the data.
“I don’t want my son to take something that is unsafe,” she said, but added, “I believe Covid is dangerous. There aren’t any good easy answers here.”
Among the side effects scientists have been studying is myocarditis, an inflammation of the heart. In rare cases, the vaccine has led to myocarditis in young people. But a large Israeli study, based on electronic health records of two million people aged 16 and older, also found that Covid was far more likely to cause these heart problems.
The Pfizer trial results were greeted enthusiastically by many school administrators and teachers’ organizations, but are unlikely to lead to immediate policy changes.
“This is one huge step toward beating Covid and returning to normalcy. I don’t think it changes the conversation around vaccine requirements for kids,” said Randi Weingarten, president of the American Federation of Teachers, a national union.
Ms. Weingarten predicted that there would not be widespread student vaccine mandates until the 2022-2023 school year. She noted that parents and educators were still awaiting full F.D.A. approval of vaccines for children aged 12 to 15, and that mandates for adults did not come until months after the shots first became available.
A significant barrier to child vaccination, she said, were widespread conspiracy theories about the shots affecting fertility.
“When people have these conversations prematurely about requirements, it adds to the distrust,” she said.
Construction workers in Melbourne, Australia, clashed violently with the police for the second day in a row on Tuesday in a dispute over mandatory vaccinations.
Up to 2,000 protesters descended into the city’s central business district, the police said. Videos posted to social media showed workers hurling bottles at the police and setting off flares, while officers in riot gear fired rubber bullets and used pepper spray. One TV journalist said he had urine thrown in his face.
The protests began after the state government in Victoria, where Melbourne is the largest city, mandated vaccinations for workers as it struggles to contain a quickly growing outbreak of the Delta variant. The demonstrators have promised to keep protesting, chanting “every day” as they marched.
The union representing construction workers has not supported mandatory vaccinations but has distanced itself from the protests, saying they were “heavily infiltrated by neo-Nazis and other right-wing extremist groups.”
Construction has been among the few industries that have largely stayed open throughout the pandemic in Victoria but the authorities have become increasingly concerned that it may be a hotbed for coronavirus transmission.
After media reports last week that three out of four construction sites were breaching virus safety rules, the state government mandated vaccinations for workers in the industry.
Australian authorities have been reluctant to mandate vaccinations beyond high-risk sectors like health care.
In response, construction workers staged sit-ins on Friday, before escalating to protests this week. On Monday, a small number of workers gathered in front of the offices of the construction union and threw projectiles at the building.
Hours later, Victoria’s premier, Daniel Andrews, ordered a two-week halt on all construction work in the state, citing “continued concern about case numbers, transmission risk and reduced compliance.”
On Tuesday afternoon, the police said they had made 44 arrests, with the number expected to grow, and that three officers had been injured and police cars attacked and damaged.
Unlike in 2020, when the U.N. General Assembly session was conducted almost entirely virtually because of the pandemic, more than 100 world leaders and other high-ranking representatives intend to deliver their speeches in person this year.
But access to the 16-acre United Nations complex in Manhattan remains strictly limited, with mandatory mask-wearing and other Covid prevention measures. Ambassador Linda Thomas-Greenfield of the United States told reporters that the measures were meant to ensure that the General Assembly “does not become a superspreader event.”
Confusion erupted last week over a New York City requirement that all General Assembly participants show proof of vaccination. This year’s president of the General Assembly, Foreign Minister Abdulla Shahid of the Maldives, endorsed the requirement. But exactly how it will be enforced is unclear.
U.N. officials have said that the organization’s headquarters staff must be vaccinated, but that an honor system remains in place for visiting V.I.P.’s and other guests.
In what appeared to be a good-will gesture, New York City’s municipal government deployed a mobile vaccine clinic outside the United Nations complex, offering free testing and Johnson & Johnson vaccines.
Many speakers this year still chose to deliver their addresses via prerecorded video, as was done by all leaders last year when vaccines were still under development and each delegation in the General Assembly hall was limited to two people. Nearly all events at the 2020 event were conducted virtually.
This year each member state may seat as many as four people in the General Assembly hall.
President Jair Bolsonaro of Brazil, an avowed vaccine skeptic whose popularity has fallen at home partly over what critics call his disastrous handling of the pandemic, vowed ahead of his speech that he would not be vaccinated.
He was infected with Covid more than a year ago and then claimed to have cured himself by taking hydroxychloroquine, an antimalarial drug that has not been shown to be effective in Covid treatment.