Rigorous trials suggest they reduce the risk of long-term disease after coronavirus infection.

Researchers are alarmed that the procedure, which has not been rigorously studied, is advertised by clinics around the world.

Cases in central Africa are rising at an alarming pace, but lessons from past epidemics could help to contain the current spread of infection.

The US Forest Service has proposed closing some three-quarters of its research sites in a move that has provoked widespread fear and uncertainty.

Budget proposal would also curb federal payments for scientific publishing.