Ahead of the first meeting of newly appointed vaccine advisers to the US Centers for Disease Control and Prevention, lawmakers are sharing fresh concerns about the panel’s membership and last-minute actions that could see Covid-19 and influenza vaccines thrown into question.

The consists of scientists, public-health experts and physicians, including one criticized for spreading COVID-19 misinformation, conspiracy theories.

Anti-vaccine advocate and current Health Secretary Robert F. Kennedy Jr. took to social media Wednesday to announce the names of eight people he is appointing to a critical federal vaccine advisory committee—which is currently empty after Kennedy abruptly fired all 17 previous members Monday.