But medics were urgently seeking to contact around 50 others for testing, most of them from the northern town of Kambia, health ministry spokesman Harold Williams said.
Sierra Leone was forced to re-open its Ebola treatment centres and relaunch screening systems, including checkpoints on motorways, late last month after two new cases of the tropical virus were confirmed.
"Forty-eight people are still classified as missing and 18 of them are high risk," he said, appealing for them to come forward.
The remaining four people in quarantine were scheduled to be released on February 11.
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There was a carnival atmosphere in the northern city of Magburaka on Wednesday where 33 people left two isolation facilities after being quarantined for three weeks.
Among the group were children, who celebrated after being told they had not shown any symptoms of being infected by the deadly tropical virus.
After their release, the town erupted in jubilation with hundreds of people taking to the streets in t-shirts reading "Stop Ebola" and "Ebola cannot defeat us", some carrying huge amplifiers blaring traditional music while others blew horns carved out of elephant tusks.
"It is an ordeal I never want to re-live," said Kadi Sesay, a 19-year-old student.
"Besides missing classes for 21 days, the quarantine period brought all of us together... The happy ending is that none of us tested positive but our thoughts were went into overdrive thinking what if we had," she said.