The panel endorsed targeting a variant of the coronavirus that is now receding, though some officials suggested aiming at newer versions of the virus that have emerged in recent weeks.

Huge die-offs of elephant seals occurred after the virus gained nearly 20 troublesome new mutations, scientists found.

The National Academies said the condition could involve up to 200 symptoms, make it difficult for people to work and last for months or years.

An independent group of experts expressed concerns that the data from clinical trials did not outweigh risks for treatment of post-traumatic stress disorder.

The organ, from a genetically modified animal, failed because of a lack of blood flow, surgeons said, but did not appear to have been rejected by the body.

An F.D.A. advisory panel dealt a setback to those seeking treatment for PTSD, citing health risks of the illegal drug and study flaws.