The United States declared measles eliminated in 2000, meaning the disease was no longer continuously spreading here. Today, measles is back, and misinformation and politics are helping fuel its return. Republican Sen. Bill Cassidy, a physician who voted to confirm Robert F. Kennedy Jr. as Health Secretary, recently condemned President Trump’s claims questioning the safety of the combined MMR vaccine. Cassidy called Trump’s comments “crazy” and “stupid,” warning that underm

As whooping cough surges across the U.S., public health experts are sounding the alarm — and for good reason. The U.S. Centers for...