Dr. Robert Malone, vice chair of the committee, was appointed by Robert F. Kennedy Jr. after a purge of the previous advisers.Dr. Robert Malone, the vice chair of the Advisory Committee on Immunization Practices, during a meeting at the C.D.C. in Atlanta in December.

Once a week, patients in an Argentine hospital with Parkinson’s disease use the movements of tango to help address issues of balance, stiffness and coordination.

The country’s experiment with psychedelic medicine has led to positive outcomes, psychiatrists say, but also highlights the limitations of the nascent field.With the blinds drawn to reduce natural light, Zoe Marshall takes a quiet moment as clinicians begin the dosing process for her MDMA-assisted therapy session in Sydney, Australia.

Many current and former employees say the actions of Health Secretary Robert F. Kennedy Jr. are undermining the agency’s role in safeguarding public health.

As deaths from diabetes start to rival those from infectious threats like malaria, a new form of the condition linked to malnutrition is surfacing in patients who can afford neither screening nor care.Habiba Sali, right, a nurse in the endocrinology department of the Maroua Regional Hospital in the far north region of Cameroon, took the vital signs of patient Aminatou Mana durin...