Robert F. Kennedy Jr., formally asked the FDA to revoke the authorization of all Covid vaccines during a deadly phase of the pandemic when thousands of Americans were still dying every week. Kennedy filed a petition with the FDA in May 2021 demanding that officials rescind authorization for the shots and refrain from approving any Covid vaccine in the future. Just six months earlier, Mr. Trump had declared the Covid vaccines a miracle. Estimates had begun to show that the rapid rollout of Covid vaccines had already saved about 140,000 lives in the United States.