SARS-CoV-2 "challenge trials" can help scientists better understand the immune system's response to the virus, which could yield improved vaccines and treatments.
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New variants of COVID-19 are emerging. Here's what scientists have learned.
Scientists are learning more about the havoc that viruses and bacteria wreak on sleep.
Action, reaction, overreaction: Once the virus gets in, the immune system can overreact—with deadly consequences.
Though they don't yet have their own Greek names, many variants of SARS-CoV-2 continue to evolve and spread.
They now account for a tenth of the nation’s COVID-19 cases.
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