Get breaking news alerts and special reports. The news and stories that matter, delivered weekday mornings.

An American health worker who caught Ebola in Sierra Leone is better, the National Institutes of Health said Tuesday. The health of the clinician, who’s been in a special unit at NIH in Maryland for three weeks, has gradually improved over that time.

“The status of the patient with Ebola virus disease being treated at the NIH Clinical Center has improved from fair to good condition. No additional details about the patient are being shared at this time,” NIH said in a statement.

Let our news meet your inbox. The news and stories that matters, delivered weekday mornings. This site is protected by recaptcha

The patient is one of 17 staffers working for the non-profit Partners in Health evacuated from Sierra Leone earlier this month.

The other 16 Partners in Health staffers were evacuated after a Centers for Disease Control and Prevention investigation showed they'd had a risky exposure either to the U.S. patient or to a Sierra Leonean doctor at the clinic who was also infected. The 16 U.S. staffers were under a 21-day watch to make sure they don't develop symptoms. That time has now passed.

Partners in Health, which says it paid for the evacuations, has not released any information about the workers or how the incident happened.

IN-DEPTH:

— Maggie Fox