The agency has long enjoyed broad bipartisan support. But Republican criticism has intensified, and new picks for top health care jobs hope to turn the organization around.
Forces opposed to President Bashar al-Assad have captured Aleppo's airport and are attacking the western city of Hama, according to local officials and a British-based war monitor.
At least 68 people have fallen ill in the outbreak believed to be linked to cucumbers sold in the United States and Canada, the Centers for Disease Control and Prevention said.
The rapid advance on Aleppo came just four days after a surprise opposition offensive that represents the most intense escalation in the civil war in years.
But over the years, the former congressman's views have often aligned with those of his potential boss, Robert F. Kennedy Jr., particularly on vaccine safety.