Coronavirus Briefing: What Happened Today

• The White House said it would send more than 25 million masks to vulnerable communities next month.

• The World Food Program warned that the pandemic could spawn a nutrition crisis for children if school meal programs wither.

• Israel pledged to give spare coronavirus vaccines to foreign allies, reigniting a debate about its responsibilities to Palestinians living under its occupation.

• Get the latest updates here, as well as maps and vaccines in development.

A third vaccine in the pipeline

Some positive news: New analyses found that the Johnson & Johnson vaccine provided strong protection against severe disease and death from Covid-19 and may also reduce the spread of the coronavirus by vaccinated people.

Over all, the report from the Food and Drug Administration found that the vaccine had an efficacy rate of about 66 percent against moderate to severe Covid cases across all of its global clinical trials. The results mean the F.D.A. could authorize the vaccine as early as Saturday, and Americans may have a third option for a vaccine as early as next week.

Some people may get tripped up on the vaccine’s 66 percent efficacy rate — compared with 95 percent for the Pfizer and Moderna shots — and wonder whether they should pass on the Johnson & Johnson vaccine and hold out for the other doses. But that figure doesn’t tell the whole story. Here are some things to keep in mind.

It’s more effective in the U.S. The 66 percent efficacy rate was calculated across all of the company’s clinical trials in the U.S., Latin America and South Africa. In the U.S., the vaccine fared better, with a 72 percent overall efficacy rate. That number dropped to 64 percent in South Africa, where a highly contagious variant is driving most cases. Even so, it’s the clear winner in South Africa so far, after Novavax’s vaccine showed an efficacy of 49 percent there, and the AstraZeneca-Oxford vaccine showed little protection at all.

It prevents severe disease. The vaccine works well where it really matters, showing 86 percent efficacy against severe forms of Covid-19 in the United States, and 82 percent against severe disease in South Africa. That means that a vaccinated person has a far lower risk of being hospitalized or dying from Covid-19.

It’s easier to take. In some ways, the Johnson & Johnson vaccine has an edge. Its one-dose shot is easier to take and has noticeably milder side effects than vaccines from Pfizer and Moderna, without any reports of severe allergic reactions like anaphylaxis.

It’s easier to distribute. Unlike vaccines from Pfizer and Moderna, which must be stored at ultracold temperatures, Johnson & Johnson’s vaccine can be stored at normal refrigeration temperatures for at least three months, making its considerably easier to distribute to rural areas and far-flung places across the globe.

Americans may not be able to pick and choose vaccines in the early stages of the rollout, and medical experts, including Dr. Anthony Fauci, have made the point that it’s important to take whichever vaccine is offered.

Sharing the vaccine with the world

The global vaccine-sharing program Covax, which aims to make vaccine access more equitable around the world, delivered its first shipment today: 600,000 doses provided by India’s Serum Institute arrived in Accra, the Ghanaian capital.

The goal of the Covax program is to deliver two billion doses this year to 92 low- and middle-income countries, for free. By doing so, Covax hopes to address an unequal system of procurement in which wealthy countries have secured enough doses to vaccinate their populations many times over, while many poorer countries have received nothing.

Even if the Covax rollout goes according to plan, vaccinating the vast majority of the world’s most vulnerable people this year will be a daunting challenge. Ghana, a nation of more than 30 million people, will get enough vaccines to cover only about 20 percent of its population by the end of 2021. It will have to buy millions more doses separately.

The vaccination campaign in Ghana and other West African countries is set to begin in the coming days, and is being rolled out as recent studies suggest that the spread of the virus has been much wider in the region than official numbers show.

Further complicating the rollout, said Dr. Tedros Adhanom Ghebreyesus, the head of the World Health Organization, is that high-income countries are competing with Covax for purchasing contracts, reducing the number of doses the initiative can buy. The pandemic will not end, he added, until everyone is vaccinated.

“This is not a matter of charity,” he said. “It’s a matter of epidemiology.”

Vaccine rollout

• Thailand, which has lagged behind some of its Southeast Asian neighbors in obtaining coronavirus vaccines, received its first shipment of 200,000 doses of the CoronaVac shot from China.

• New York State opened two large vaccination sites in Brooklyn and Queens, part of an effort to boost inoculations in neighborhoods that have been hit particularly hard by the pandemic.

• State Department officials overseas expressed anger and disappointment that diplomats in Washington were being vaccinated before those in more perilous posts.