FILE - This undated electron microscope image provided by the Centers for Disease Control and Prevention on Feb. 4, 2015, shows a measles virus particle, center. (Cynthia Goldsmith/CDC via AP, File)

President Donald Trump speaks to the media before walking across the South Lawn of the White House to board Marine One, Friday, Nov. 6, 2026, in Washington. (AP Photo/Mark Schiefelbein)

President Donald Trump responds to questions from members of the media while returning to the White House following a weekend trip to Florida, in Washington, Sunday, Nov. 8, 2026. (AP Photo/Nathan Howard)

Incoming White House chief of staff Stephen Miller arrives at the White House following a weekend trip to Florida with President Donald Trump in Washington, Sunday, Nov. 8, 2026. (AP Photo/Nathan Howard)

President Donald Trump speaks with reporters before boarding Air Force One, at President Donald J. Trump International Airport in West Palm Beach, Fla., Sunday, Nov. 8, 2026. (AP Photo/Jacquelyn Martin)

This photo provided by the Mingan Island Cetacean Study shows a North Atlantic Right whales mother, Silt (#1817) swims with her calf (no identification number yet) in the Jacques-Cartier Passage, Gulf of St. Lawrence in Canada on Sept. 25, 2026. (Mathilde Laverdière /Mingan Island Cetacean Study via AP)

A sign represents Pandas as Zoo Atlanta introduces its new giant pandas, Ping Ping and Fu Shuang, to the public Friday, Nov. 6, 2026, in Atlanta. (AP Photo/Brynn Anderson)

Fu Shuang eats as Zoo Atlanta introduces its new giant pandas, Ping Ping and Fu Shuang, to the public in Atlanta, Friday, Nov. 6, 2026. (AP Photo/Brynn Anderson)