The Coronavirus Brazil Variant Shows the World's Vulnerability - The Atlantic - 0 views
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Though many questions remain, one plausible explanation is that people who have already been infected by the virus are getting sick—and not mildly so. That possibility has been long feared throughout the pandemic, yet not previously seen on any significant scale
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Although no known variants have been found to pose an immediate threat to vaccinated people, the capacity for reinfection to any significant degree would reshape the pandemic’s trajectory.
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The new wave of COVID-19 cases in Manaus occurred about eight months after the initial wave. People might have lost some degree of immunity during that window.
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Two important factors seem to be playing a role in Brazil’s resurgence. The first is that, after a COVID-19 infection, the natural immunity that our bodies develop seems to vary in strength and permanence. Protection wanes after infection with most respiratory viruses, including coronaviruses
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the variant in Brazil, known as the P.1 (or B.1.1.248) lineage, has a potent combination of mutations. Not only does this variant seem to be more transmissible; its lineage carries mutations that help it escape the antibodies that we develop in response to older lineages of the coronavirus.
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it at least has a capacity to infect people who have already recovered from COVID-19, even if their defenses protect them against other versions of the virus.
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The mutations that help the virus spread and evade immune responses have arisen independently in multiple places. Combined with waning immunity, these factors underscore the challenge before the world: Populations may still be vulnerable to disaster scenarios just when things seem to be getting better.
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the virus’s capacity to cause such a deadly second surge in Brazil suggests a dangerous evolutionary potential.
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New, dangerous variants are all but inevitable when there are extremely high levels of transmission of the virus. As more people gain immunity, the selective pressure on the virus will favor the variants that can most effectively evade immune responses
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the basic nature of evolutionary biology means that the virus should be expected to evolve in ways that circumvent defense mechanisms. Evidence that it is already doing so has been clear in the latest vaccine trial data.
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The solution, then, depends on vaccination. The immune response that the vaccines create is generally more robust than the immune response we get after being infected by a virus, and should buy a population more protected time than would a surge in exposure to the virus
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In most places, however, this is not close to happening. And as of last week, only one of the world’s 29 poorest countries had vaccinated anyone at all. A study in the journal BMJ estimated that vaccines will not be available to more than a fifth of the world’s population until 2022.
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The coronavirus’s constantly evolving nature is a stark reminder that the entire world is in this crisis together.
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Ensuring that every human is vaccinated is in everyone’s interest, as global distribution of vaccines is the most effective way to drive down the virus’s capacity to replicate and evolve.
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The key will be bringing down the global rates of transmission as quickly as possible—not getting any single country to 100 percent vaccination while dozens of countries roil.
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“It is truly confounding that wealthier nations think that hoarding vaccines is the way to protect their citizens from a global pandemic that doesn’t respect borders,”
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As the virus currently surges across Africa, some 2.5 million health-care workers are unvaccinated. “Clearly, the failure to address vaccine allocation based on health and epidemiological needs, rather than national interest, is now promising to have a dire impact on the world’s ability to achieve rapid, global control of COVID,”
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Certain countries will approach herd immunity by vaccinating almost every citizen. Other countries could see mass casualties and catastrophic waves of reinfection—potentially with variants that evolved in response to the immunity conferred by the very vaccines to which these populations do not have access. In the process, these hot spots themselves will facilitate rapid evolution, giving rise to even more variants that could make the vaccinated populations susceptible to disease once again