The fast-spreading omicron variant has heightened the need for billions of additional vaccine doses to protect vulnerable populations and tamp down new variants around the world, according to a new report prepared by a team of public health advocates and scientists.

“The scientific evidence is clear: only by universally deploying the vaccines currently most effective against infection — which for now appear to be mRNA vaccines — will we be able to blunt the virus’s evolution and begin to bring the pandemic under control globally,” the authors write in the report, which was first shared with The Washington Post.

The authors — who include advocates at PrEP4All and Partners In Health and scientists at Harvard Medical School, Columbia University, New York University and the University of Saskatchewan — conclude that about 22 billion doses of high-quality mRNA vaccines are now needed to slow the pandemic’s spread, given the omicron variant’s ability to evade some of the immune protection conferred by prior vaccination shots. That projection would require producing an additional 15 billion doses of mRNA vaccines this year.

“With the pandemic, the global is the local. And the local is the global,” said James Krellenstein of PrEP4All, pointing to the omicron variant’s recent emergence in southern Africa as the latest illustration of how virus variants jump borders. “What happens in Cape Town influences what happens in Brooklyn three weeks later. And what happened in Wuhan influenced what happened in Brooklyn six weeks later.”

The authors also stressed that the mRNA vaccines have demonstrated the best protection against multiple virus variants, including by providing cross-protective T-cell immunity that reduces disease severity after infection.

“If we don’t want to keep playing variant whack-a-mole, it’s crucial that we scale up global access to the most effective vaccines we have access to,” Angela Rasmussen, a virologist at the Vaccine and Infectious Disease Organization at the University of Saskatchewan, told The Post.

The advocates’ call for billions of additional mRNA doses is far more aggressive than targets laid out by global leaders, who have set a goal of “fully vaccinating” 70 percent of the world’s population by September through a variety of vaccines, including non-mRNA shots, in the hope of curbing the most severe aspects of the pandemic.

Biden administration officials on Wednesday also said they were dubious that so many additional mRNA vaccine doses would be needed given the pace of vaccination campaigns so far. More than 9 billion vaccine doses have already been administered globally, and about 50 percent of the global population is now “fully vaccinated,” according to data compiled by the University of Oxford’s Our World in Data project.

However, more than 3 billion people around the world have yet to receive a single dose of coronavirus vaccine, according to the University of Oxford’s data. Many low-income nations also have relied on vaccines such as China’s Sinovac, which appear to be less effective at warding off omicron infections than the mRNA shots produced by Moderna and Pfizer-BioNTech.

While vaccines continue to work to defang the worst consequences of coronavirus infections, leading to mild symptoms in many previously vaccinated people, omicron’s ability to evade antibodies conferred by vaccinations has posed new challenges for global strategies to fight the pandemic. Public health experts around the world, including federal agencies in the United States, have recommended that people seek out mRNA booster shots to raise their immune protection against the new variant.

The rapid spread of omicron also has prompted advocates and Democrats to again call on U.S. leaders to move faster on helping to vaccinate the globe.

President Biden has vowed that the United States will be an “arsenal of vaccines” for the world, pledging to donate more than 1 billion doses to other nations, a total that far outpaces that of other countries. The Biden administration also has moved to invest billions of dollars in expanding vaccine manufacturing capacity to support global needs.

“We continue to do everything we can, and our feet are still on the gas to do more,” said White House spokesperson Kevin Munoz, pointing to recent efforts by the State Department, the United States Agency for International Development and other agencies to coordinate a global omicron response. “Manufacturing and delivering more vaccines is vital, and we are also focused on significantly ramping up the global effort to get shots into arms to turn vaccines into vaccinations.”

Meanwhile, vaccine manufacturers have warned that limits on raw materials have constrained their ability to produce new doses, and other factors could further delay doses. “If a variant-updated vaccine is needed, production rate in 2022 would slow initially,” Airfinity, a health data research firm, warned last month.

But the report’s authors said the White House had disregarded a year of warnings to more quickly ramp up mRNA vaccine production. Only 7 billion vaccine mRNA vaccine doses are expected to be produced this year, according to manufacturers’ projections.

“You are not going to protect the American people — full stop, it does not work — until you work, seriously, to bring the pandemic under control globally,” Krellenstein said. “And the administration has not learned that lesson.”

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