The World Health Organization declared Liberia free of Ebola for a second time Thursday after a brief resurgence of the disease.
Liberia was the country hardest hit in the largest Ebola epidemic on record, accounting for more than 4,800 of the 11,300 people killed by the virus since the end of 2013.
The outbreak there was declared over in May after no new cases were reported for 42 days, twice the usual incubation period for the virus. But six additional cases were later identified, including two people who died, the WHO said in a statement.
Health officials reiterated Thursday that the country won't be safe from Ebola until the virus has been defeated throughout West Africa.
In neighboring Sierra Leone, tests confirmed Saturday that a woman believed to be in her 60s had died of Ebola less than a week after the last-known patient in the country was discharged from a treatment center.
Those who came into contact with the victim and their contacts are being offered an experimental vaccine that has shown promising results in trials in neighboring Guinea, the WHO said. Those trials are being extended to Sierra Leone.
Guinea, where the epidemic began, reported two more cases last week.
Liberia now enters a 90-day period of heightened surveillance during which authorities will be on the lookout for any possible cases, the WHO said.