According to WHO data, there have been 1,406 confirmed cases of the disease in DRC, with 301 suspected cases and 438 deaths.
The World Health Organization's director general says no further cases have been reported since 25 May.
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IAVI, Moderna and the University of Oxford are all working on new vaccines.
The medical charity's comments come as the head of the World Health Organization visits the region worst-hit by the virus outbreak.
The head of the UN health agency says the risk in the wider region is "high", but it remains "low" at the global level.
In its latest update, the World Health Organization says there have now been 139 suspected deaths and 600 cases.
Hundreds of cases are suspected in central Africa but experts fear the actual number may be much higher.
The World Health Organization has declared this Ebola outbreak a "public health emergency".
