In the 18 days since Robert F. Kennedy Jr. was sworn in as secretary of the United States Department of Health and Human Services, his department has postponed or canceled two major vaccine advisory committee meetings,

A top spokesman in the U.S. Department of Health and Human Services abruptly resigned over reports of internal clashing over management and escalating health emergencies.

WASHINGTON—Amid a growing outbreak of measles in Texas, recently confirmed Health Secretary Robert F. Kennedy Jr. is urging parents to vaccinate their children against the disease.