poses universal risks by allowing variants to take hold, forcing the world into an endless cycle of pharmaceutical catch-up.

“It needs to be global leaders functioning as a unit, to say that vaccine is a form of global security,” said Dr. Rebecca Weintraub, a global health expert at Harvard Medical School. She suggested that the G7, the group of leading economies, could lead such a campaign and finance it when the members convene in England next month.

Pfizer expects to sell $26 billion worth of Covid vaccines this year; Moderna forecasts that its sales of Covid vaccines will exceed $19 billion for 2021.

History also challenges industry claims that blanket global patent rights are a requirement for the creation of new medicines. Until the mid-1990s, drug makers could patent their products only in the wealthiest markets, while negotiating licenses that allowed companies in other parts of the world to make generic versions.

Even in that era, drug companies continued to innovate. And they continued to prosper even with the later waivers on H.I.V. drugs.

“At the time, it rattled a lot of people, like ‘How could you do that? It’s going to destroy the pharmaceutical industry,’” recalled Dr. Anthony S. Fauci, President Biden’s chief medical adviser for the pandemic. “It didn’t destroy them at all. They continue to make billions of dollars.”

Leaders in the wealthiest Western nations have endorsed more equitable distribution of vaccines for this latest scourge. But the imperative to ensure ample supplies for their own nations has won out as the virus killed hundreds of thousands of their own people, devastated economies, and sowed despair.

The drug companies have also promised more support for poorer nations. AstraZeneca’s vaccine has been the primary supply for Covax, and the company says it has sold its doses at a nonprofit price.

stumbled, falling short of production targets. And producing the new class of mRNA vaccines, like those from Pfizer-BioNTech and Moderna, is complicated.

Where pharmaceutical companies have struck deals with partners, the pace of production has frequently disappointed.

“Even with voluntary licensing and technology transfer, it’s not easy to make complex vaccines,” said Dr. Krishna Udayakumar, director of the Duke Global Health Innovation Center.

Much of the global capacity for vaccine manufacturing is already being used to produce other lifesaving inoculations, he added.

But other health experts accuse major pharmaceutical companies of exaggerating the manufacturing challenges to protect their monopoly power, and implying that developing countries lack the acumen to master sophisticated techniques is “an offensive and a racist notion,” said Matthew Kavanagh, director of the Global Health Policy and Politics Initiative at Georgetown University.

With no clear path forward, Ms. Okonjo-Iweala, the W.T.O. director-general, expressed hope that the Indian and South African patent-waiver proposal can be a starting point for dialogue.

“I believe we can come to a pragmatic outcome,” she said. “The disparity is just too much.”

Peter S. Goodman reported from London, Apoorva Mandavilli from New York, Rebecca Robbins from Bellingham, Wash., and Matina Stevis-Gridneff from Brussels. Noah Weiland contributed reporting from New York.

View

Is It Covid or the Flu? New Combo Tests Can Find Out.

“We in the laboratory are preparing for another big boom in testing,” said Dr. Baird, whose team has run more than two million coronavirus tests since the beginning of the pandemic. “Even if people are vaccinated, they’re going to wonder, ‘Am I the breakthrough case?’”

In addition to Cepheid, other companies have developed tests that look for influenza and the coronavirus at the same time, including Roche, which has received emergency use authorization for a test that looks for the coronavirus, influenza A and influenza B at once.

In recent years various hospitals have developed in-house versions of these combination tests as well, some of which look for more than a dozen different respiratory pathogens simultaneously using P.C.R. technology. Those “multiplex” tests are especially helpful in diagnosing illnesses in people with weak immune systems because they allow doctors to swiftly discern what pathogen is making a person sick before it is too late to start the right treatments.

A French company, bioMérieux, sells a P.C.R. test that looks for the coronavirus as well as 21 other viruses and bacteria simultaneously. And Roche recently bought a company that sells a machine that can screen for more than 20 pathogens in one go.

Testing for multiple pathogens does not always lead to a simple treatment, however. Co-infections, in which a person is infected with multiple viruses simultaneously, are more common than doctors expected, and sometimes the multiplex tests might detect a viral infection but miss a bacterial one, said Dr. Daniel Griffin, chief of infectious diseases at ProHealth New York. A patient could carry the influenza virus but also test positive for a bacterium such as pneumococcus, for example.

“We initially thought that every time we identified a virus, we would just be able stop all antibiotics and just treat the virus if effective antiviral therapy was available,” Dr. Griffin said. “We now know that we often need to continue antibiotics,” he explained, because sometimes the multiplex tests are not sensitive enough to rule out a bacterial culprit.

Doctors and test developers are still grappling with how many pathogens to test patients for in different settings. “A burning question at every company is what panel is best — is it one, two, four, 20?” said Dr. Mark Miller, chief medical officer at bioMérieux. Relatively young and healthy adults might just need a quad test to know if they should start on Tamiflu for influenza, for example, but patients with underlying chronic diseases who are very sick might benefit from receiving the test for 22 different pathogens so that doctors can decide whether they need to be admitted to a hospital.

View

Antibody rates among Black and Hispanic New Yorkers are double those of others, new estimates show.

New York City health officials estimate that nearly a quarter of adult New Yorkers were infected with the coronavirus during the catastrophic wave of last spring, and that the toll was even higher among Black and Hispanic residents.

The estimates, based on antibody test results for more than 45,000 city residents last year, suggest that Black and Hispanic New Yorkers were twice as likely as white New Yorkers to have had antibodies to the coronavirus — evidence of prior infection.

Hispanic New Yorkers had the highest rate, with about 35 percent testing positive for antibodies, according to the study, whose authors include officials and researchers at the city Health Department and the National Institute for Occupational Safety and Health. Among Black New Yorkers, 33.5 percent had antibodies. Among Asian New Yorkers, the rate was about 20 percent. For white New Yorkers, the rate was 16 percent.

Antibody surveys of segments of the population have become a useful way to gauge what percentage of people were infected and what groups were most at risk, especially since there was limited testing for the virus during the first wave.

The new paper, which has been accepted by the Journal of Infectious Diseases, has substantial limitations: Of the 45,000 New Yorkers in the study, fewer than 3,500 were Black, a major underrepresentation. And the participants were recruited partly through advertisements online, which the study’s authors acknowledge may have attracted people who believed they had been exposed to Covid-19.

But the study adds to experts’ understanding of the disproportionate toll that the pandemic has taken on Black and Latino people.

Its findings also come amid a push to vaccinate more people in the United States. A recent survey conducted by the Kaiser Family Foundation found that the number of Americans, particularly Black adults, who want to get vaccinated has continued to increase. According to an analysis last month by The New York Times, Black people were still being inoculated at half the rate of white people. The disparities are especially alarming as Black and Latino people and Native Americans have been dying at twice the rate of white people.

In New York City, about 44 percent of white adults have received at least one dose of a Covid-19 vaccine, while 26 percent of Black adults and 31 percent of Latino adults have, according to city data.

Experts and community leaders across the country say that over all, the lower vaccination rates are linked to technological and linguistic barriers and disparities in access to vaccination sites. Other factors include social media misinformation and a hesitancy to be vaccinated. Hesitancy among African-Americans, experts say, can be tied to a longstanding mistrust of medical institutions that have long mistreated Black people.

have comparatively fewer white workers.

“These were the people who did not have the luxury of being able to work virtually,” she said.

Dr. Kitaw Demissie, who is dean of the School of Public Health at SUNY Downstate Medical Center in Brooklyn and was not involved in the study, noted that household crowding may have also contributed to differing infection rates. Some predominately Latino neighborhoods which were particularly hard hit in the first wave had high rates of household crowding.

More than 32,000 people in New York City have died from Covid-19 in total, according to a New York Times database.

View