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Pfizer to Test Second Paxlovid Course in Patients With Covid Rebound

  • CEO Bourla had suggested second course when rebound surfaced
  • Biden, Fauci both experienced rebound after taking Covid drug
Pfizer CEO Albert Bourla
Pfizer CEO Albert BourlaHollie Adams/Bloomberg

Pfizer Inc. was ordered by US regulators to test the effects of an additional course of Paxlovid among people who experience a rebound in Covid-19 after treatment, putting the drug through further study as reports of the mysterious phenomenon continue to mount.

The company must produce initial results of a randomized controlled trial of a second course of the antiviral by Sept. 30, 2023, according to a letter from the regulator to Pfizer dated Aug. 5. The letter, which describes changes in Paxlovid’s emergency authorization, was confirmed by the Food and Drug Administration in an email.