President Biden’s recent case of Covid-19, its rebound, and his extended isolation offers an opportunity to consider how more precise interpretation of viral load via PCR testing might be used to safely return people to work or school earlier.
Biden tested positive for SARS-CoV-2, the virus that causes Covid-19, on July 21, after beginning to experience a runny nose, dry cough, and fatigue the night before. He took the antiviral Paxlovid for five days, as prescribed. He felt well, and serial testing indicated that his body had cleared the virus on July 26. He returned to work on July 27, consistent with guidelines set by the Centers for Disease Control and Prevention. Yet on July 30, the president tested positive again, and was “forced to resume strict isolation procedures” despite feeling fine, according to a memo from his physician, Kevin C. O’Connor.
This decision, well within current norms for care, was nonetheless consequential: The president was forced to cancel a trip to advocate for legislation in support of the domestic semiconductor industry, despite feeling fine. It wasn’t until Aug. 7 that he returned to “public engagement and presidential travel.”
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The re-emergence of the SARS-CoV-2 virus after treatment — also known as Paxlovid rebound — is increasingly recognized by clinicians. It may happen when a reservoir of virus is suppressed by antiviral therapy but not eradicated by it. This rebound suggests that new strategies, such as increasing treatment time from 5 to 10 days, should be evaluated, since the virus can apparently linger in individuals who have no symptoms, with or without treatment.
This raises a key question: Do such individuals harbor enough virus to be contagious to others?
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Current recommendations for returning to school or work (which the Washington Post and others have called confusing) rely on empiric observations: symptoms and the timing and results of Covid tests, usually the rapid antigen tests such as the at-home tests provided by the federal government. The imprecision of such guidance leaves uncertainty for b …