He also has years of experience treating heroin addicts, who account for as many as half of the H.I.V. and AIDS patients the institute treats. And he has been a longtime proponent of medical assisted treatment for addiction.
“I think he’s a superb candidate, first rate,” said Kathleen Kennedy Townsend, a Democrat and a former lieutenant governor of Maryland.
Ms. Townsend, who got to know Dr. Redfield while serving on the board of the Institute of Human Virology, said his background in infectious diseases and the opioid epidemic made him the right person for the job. “Ebola could come up next year, either naturally or in an attack,” she said. “We have to be prepared, and he understands that.”
She said Dr. Redfield once proposed that every hospital spend at least 10 percent of its budget to treat addiction.
Dr. Redfield’s career has not been without controversy. As an early AIDS researcher, he proposed mandatory testing, a prospect that was opposed by many liberals and gay activists.
A graduate of Georgetown University and Georgetown University School of Medicine, Dr. Redfield did his residency in internal medicine at Walter Reed Army Medical Center. He is a member of the Presidential Advisory Council on H.I.V./AIDS and recently finished terms on advisory boards for the National Institutes of Health.
Dr. Redfield is a practicing Catholic, whose faith plays a large role in his life, according to friends and family. He is married to a nurse, Joy, whom he met while delivering babies.
The couple have six children and nine grandchildren.
Dr. Fitzgerald was appointed by Tom Price, a fellow Georgian who served as President Trump’s first secretary of Health and Human Services. Mr. Price resigned in September under criticism for traveling extensively on private jets and billing the government more than $400,000 for the trips. Dr. Anne Schuchat has been acting director.