The central African country is battling its latest upsurge in the disease in the conflict-ridden east, a region scarred by more than three decades of violence.
Ebola, which spreads through contact with bodily fluids and causes haemorrhagic fever, has killed more than 15,000 people across Africa over the past 50 years.
The deadliest outbreak in the DRC killed nearly 2,300 people out of 3,500 recorded cases.
On Friday, Congolese officials published data showing 3,532 cases of Ebola had been confirmed across five provinces, including 1,556 deaths.
Medics had recorded 2,000 confirmed cases on July 15, two months after the outbreak was declared.
The DRC’s 17th Ebola outbreak is caused by the Bundibugyo strain of the virus, for which there is no approved vaccine or treatment.
A vaccine described by the World Health Organization as the “most promising” to fight the current outbreak will be developed by Singapore-based Hilleman Laboratories, it announced on Thursday.
Last week, a first volunteer received the first dose of a different Bundibugyo vaccine being developed by Oxford University under a clinical trial.
The centre of the current outbreak, whose true extent is still hard to assess, is northeastern Ituri province, which borders South Sudan and Uganda.
The virus has also been detected in four other provinces including North Kivu and South Kivu where provincial capitals and large swathes of land are controlled by the Rwanda-backed M23 armed group.
Uganda declared it was Ebola-free this week after the recovery of the last case of local transmission. But the WHO says the country remains at risk from the spread in its neighbour.
