FILE - Daniel Aragonez leaves a cooling center in Los Angeles, July 31, 2026. (AP Photo/Jae C. Hong, File)

FILE - Ruth, 11, from Burke, Va., gets cold water poured on her head to cool off at the Great American State Fair on the National Mall, July 2, 2026, in Washington. (AP Photo/Alex Brandon, File)

FILE - Mickelina Papotto, of Salem, Ore., left, and Lorie Odegaard, of Gaithersburg, Md., fan themselves while waiting in line for the ferris wheel at the Great American State Fair on the National Mall, July 1, 2026, in Washington. (AP Photo/Jacquelyn Martin, File)

National Institutes of Health Director Dr. Jay Bhattacharya speaks during a meeting to sign an executive order about vaccines, Monday, Aug. 10, 2026, in the Oval Office of the White House in Washington. (AP Photo/Jacquelyn Martin)

Health and Human Services Secretary Robert F. Kennedy Jr. speaks during a meeting to sign an executive order about vaccines, Monday, Aug. 10, 2026, in the Oval Office of the White House in Washington. (AP Photo/Jacquelyn Martin)

President Donald Trump listens during a meeting to sign an executive order about vaccines, Monday, Aug. 10, 2026, in the Oval Office of the White House in Washington. (AP Photo/Jacquelyn Martin)

Health and Human Services Secretary Robert F. Kennedy Jr. speaks as President Donald Trump listens during a meeting to sign an executive order about vaccines, Monday, Aug. 10, 2026, in the Oval Office of the White House in Washington. (AP Photo/Jacquelyn Martin)

President Donald Trump holds up an image taken from his Truth Social account as Health and Human Services Secretary Robert F. Kennedy Jr. watches during a meeting to sign an executive order about vaccines, Monday, Aug. 10, 2026, in the Oval Office of the White House in Washington. (AP Photo/Jacquelyn Martin)