WASHINGTON, DC - AUGUST 10: White House Deputy Chief of Staff and Homeland Security Advisor Stephen Miller attends an event before U.S. President Donald Trump signs an executive order calling for childhood vaccine shots to be spaced out into separate visits during an event in the Oval Office of the White House on August 10, 2026 in Washington, DC. During his second term, Trump has urged Health and Human Services Secretary Robert F. Kennedy Jr. to investigate further research on vaccines. (Photo by Anna Moneymaker/Getty Images)