One of the nation’s leading AIDS researchers and an expert in the treatment of heroin addiction is the leading candidate to oversee the Centers for Disease Control and Prevention.

A formal announcement about the candidate, Dr. Robert R. Redfield, could come as early as Tuesday, once the vetting has been finished, said an administration official with knowledge of the appointment, who was not authorized to speak publicly.

The review process is likely to be thorough. President Trump’s first C.D.C. director, Dr. Brenda Fitzgerald, resigned in January after about six months amid reports that she held investments in tobacco and health care companies that posed potential conflicts of interest.

A professor at the University of Maryland School of Medicine, Dr. Redfield founded the Institute of Human Virology along with Dr. Robert C. Gallo, who developed the blood test for the human immunodeficiency virus.