Senator Ron Wyden, the top Democrat on the Senate Finance Committee, and Democratic Senator Elizabeth Warren also asked that Kennedy, who is Republican Trump's choice to lead the Department of Health and Human Services, pledge not to engage in lawsuits involving vaccines for at least four years after leaving office.

Two Democratic senators on the committee that will get to decide whether to advance Robert F. Kennedy Jr.'s nomination say his recent financial disclosure filing gave them “grave concern” about whether he should become the next health and human services secretary.