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Omicron could derail efforts to reverse vaccine inequality and end the pandemic, experts warn
2021-12-24 00:00:00.0     华盛顿邮报-世界     原网页

       The rapid spread of the omicron variant could be a major setback for efforts to reverse sharp inequality in the accessibility of effective coronavirus vaccines around the world, public health experts warn.

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       That could mean longer delays for vaccination programs in poor countries, leaving large populations unprotected and prolonging the circumstances under which experts say dangerous variants are most likely to emerge.

       A subsequent increase in demand for mRNA vaccines and booster doses, which appear to offer the best protection against omicron, would drive a widening of the divide, as rich countries accrue more doses and poor ones continue to go without or face long delays and uncertainty.

       Wealthy nations rush boosters to counter omicron as poorer nations await first doses

       After a global run on doses, logistics have supplanted availability as the chief obstacle to vaccinating the world’s neediest, World Health Organization vaccine director Kate O’Brien told The Washington Post earlier this month. But omicron could bring availability problems soaring back, experts fear.

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       “The inequalities are worsening,” said Tsion Firew, an assistant professor at the Columbia University Medical Center and adviser to Ethiopia’s Ministry of Health. “Especially as the omicron variant is widely spreading in places like the United States,” which continues to record a rate of per capita deaths among the highest in the world, “we are going to see more vaccine hoarding and we are going to see it become more difficult for low-income countries to access” doses, she said.

       In a news conference on Wednesday, the WHO once again urged countries to wait on administering widespread boosters, and to instead focus on ensuring first and second doses globally.

       There’s still much to learn about omicron. But initial studies show that the highly contagious variant more easily evades vaccines, though vaccinated people remain at a far lower risk of developing severe disease.

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       Coronavirus vaccines also do not appear to protect against omicron equally: Newer mRNA vaccines produced by Pfizer and Moderna seem to be more effective, according to the first round of research, than technologies used by Johnson & Johnson, AstraZeneca, Russia’s Sputnik, and China’s Sinopharm and Sinovac — which produces the world’s most widely used vaccine.

       Booster doses of mRNA vaccines further increase the likelihood of preventing infection, according to initial laboratory trials. But a Sinopharm booster showed a “significantly lower” chance of neutralizing omicron, according to a recent study by researchers in Shanghai, Reuters reported.

       About 30 percent of the fully vaccinated in the U.S. have gotten boosted. Omicron could speed things up.

       “What that says is that most of the world is vulnerable to infection at a mass scale,” said J. Stephen Morrison, director of the Global Health Policy Center at the Center for Strategic and International Studies, a Washington-based think tank. “The geopolitics around vaccines are going to get much, much worse,” he added.

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       In poor countries, where vaccination rates remain low and AstraZeneca and Sinovac account for many of the doses distributed, any setback is especially costly. In contrast, in Europe and North America, and countries including Israel and the United Arab Emirates, vaccination rates are high and Pfizer or Moderna booster shots predominate.

       Global vaccine inequality runs deep. Some countries say intellectual property rights are part of the problem.

       Initial laboratory studies tell only part of the story, said Krishna Udayakumar, founding director of the Duke Global Health Innovation Center. More time-consuming clinical trials will offer a fuller picture of the performance of vaccines in the face of the omicron variant.

       But it is already apparent, Udayakumar said, that for best protection, “everyone will need a third dose of a vaccine for higher protection given the emergence and pending dominance of omicron.”

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       That will be an uphill battle in much of the world. Just 8.6 percent of the 1.3 billion people across Africa, for instance, are fully vaccinated, a status that does not include boosters. By comparison, nearly 62 percent of the United States’ population of 330 million is fully immunized — and more than 60 million booster shots have been given out.

       “Omicron is a prime example of why we need to ramp up global vaccination efforts — not just providing vaccines, but also ensuring barriers to distribution and getting shots in arms are addressed and overcome,” Saskia Popescu, an infectious-disease epidemiologist at the University of Arizona and George Mason University, said in an email. “It’s not enough just to send several million [doses to lower-income countries], but also provide resources (people, storage, vehicles, educational resources, etc.) to ensure they are meeting the end target — equitable vaccine distribution globally,” she continued.

       South Africa’s huge omicron wave appears to be subsiding just as quickly as it grew

       Covax, the United Nations-led effort to get vaccines to lower- and middle-income countries, is racing to deliver 800 million doses by the year’s end — far off from its pledge of 2.3 billion.

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       Adding to the imbalance is the question of emerging disparities between vaccines.

       Vaccine manufacturer Moderna, citing preliminary data, said Monday its booster raised antibody levels against the omicron variant by 37 percent and that a dose double that of a standard booster increased levels by 83 percent. While a study by Discovery Health, South Africa’s largest health insurer, reported that two doses of Pfizer provided just 33 percent protection against omicron infection, a laboratory study by the company said its booster shot saw a 25-fold increase in the level of neutralizing antibodies.

       A more dire scenario is emerging in preliminary studies on non-mRNA vaccines, such as AstraZeneca, which 99 percent of vaccinated people in India have received, and Sinopharm and Sinovac, which China has distributed domestically and globally.

       Covax promised 2 billion vaccine doses to help the world’s neediest in 2021. It won’t even deliver even half that.

       A study by the U.K. Health Security Agency found that two doses of either the AstraZeneca or Pfizer vaccine did not provide adequate protection against an omicron infection: Though the data pool was small, AstraZeneca offered the least of the two. The Pfizer booster, the study found, would likely increase the chance of neutralizing the virus by 70 to 75 percent.

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       A study in Hong Kong testing the blood samples of 25 people vaccinated with Sinovac found nearly no antibody protection from omicron. A Sinopharm booster also failed to spur significant neutralization of omicron in a Shanghai laboratory study.

       Given this preliminary data, said Morrison of the Global Health Policy Center, China “is not going to be able to suppress and contain” omicron.

       A clearer picture of the variant’s impact will emerge in the coming weeks — though scientists fear that, even if it proves milder than previous variants, already strained health systems could still be overwhelmed by an influx of patients coupled with reduced staff due to widespread exposures.

       Highly vaccinated countries thought they were over the worst. Denmark says the pandemic’s toughest month is just beginning.

       In the meantime, the Columbia University Medical Center’s Firew said face masks and coronavirus vaccines of every kind, along with tests, remain a critical first defense.

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       “What vaccines are doing is preventing death and severe illness,” she said. “Some have a higher protection than the other ones. But any vaccine is better than no vaccine.”

       Firew said omicron could offer a moment of global reckoning and reorienting of priorities, such as sharing mRNA technologies, to increase vaccine production and access “for all vulnerable populations around the world.”

       “Really grotesque inequities exist, which have made it possible for these dangerous variants to evolve,” Morrison said. “The huge mistake we made in the past year is that such large segments of the world have uncontrolled” transmission.

       


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