Liberia, Guinea and Sierra Leone - the three worst affected countries by Ebola - have not reported a confirmed new case of since September.
This is the first time a week has passed without a contamination since the Ebola outbreak first started in March 2014.
The World Health Organisation says Ebola has killed more than 11,000 people since then, the vast majority of them in West Africa.
A British national, aid worker Pauline Cafferkey, was also infected with the virus but survived after being treated in the UK.
Jeanne Kamara, Christian Aid's Country Manager for Sierra Leone, told Premier's News Hour: "Slightly relieved, but still not complacent, but quite pleased that there's some progress and we seem to be moving things along in the right direction.
"I think what needs to happen [now] is the community needs to stay involved, there needs to be coordination and collaboration, working with everyone.
"We need to continue to have clear leadership and we need to have a structure... at national and district level, and at village level as well.
"And critically I think we need to keep harping on about the messages not to wash dead bodies, not treat sick people and to call 117 if people are sick.
"We really welcome even more prayers and we hope that our listeners will join the people and friends of Sierra Leone in praying for the final end to Ebola."
Listen to Premier's Marcus Jones speaking to Jeanne Kamara here: