An American physician isolated at the National Institutes of Health Clinical Center after being exposed to Ebola in Sierra Leone was discharged Tuesday and did not show signs of the virus, the NIH said Tuesday.

In a statement, the NIH said that the patient was admitted to an isolation unit in Bethesda, Md., on Sept. 28 after returning from Sierra Leone, where he had been exposed to the virus by a needle stick injury. He was a volunteer in an Ebola unit in Sierra Leone.

During his period of isolation at NIH, he briefly developed a fever that turned out not to be Ebola-related. The NIH said that he will remain in his own home and officials will monitor his temperature twice a day for 21 days from the time of the needle prick, the longest duration that the virus might take to cause symptoms.

He is currently feeling well, the statement said. The NIH has not released the doctor’s name.