West Africa is about to receive a hefty infusion of cash. This Friday the World Bank unveiled a major aid package for the three West African countries at the center of this past year's Ebola epidemic.

Over the next 18 months, the bank plans to provide Sierra Leone, Liberia and Guinea $650 million in recovery assistance, mostly in the form of grants. The African Development Bank followed suit Friday with a pledge of about $300 million in similar funding.

Combined with additional new promises by other international organizations and governments, the three affected countries will be getting more than $1 billion. Those additions boost the total international commitment to Ebola recovery since the outbreak began by about a third, the advocacy group One Campaign reports.

The aid comes amid recent steady declines in the number of new cases in the region. Weekly tallies are now down to fewer than 40 cases — their lowest level since last May, when the outbreak was just beginning to gather steam.

Still, the economic and social repercussions of the epidemic continue to reverberate.

In Sierra Leone, the Ebola crisis coincided with a plunge in the price of iron ore, one of the country's major exports. The economy there could end up contracting by more than 20 percent in 2015, the World Bank estimates.

Guinea's economy is stagnating. Liberia is projected to see growth rates of about 3 percent, but that's still well below the pre-Ebola estimates of 6.8 percent.

At the same time, all three countries are plagued with poor infrastructure and fragile health systems — which are still reeling from the loss of dozens of health workers to Ebola.

Meanwhile, the effort to bring cases down to zero continues to grind forward. Liberia has not had a single new case since late March. Sierra Leone is in sight of that goal as well, said the World Health Organization's Bruce Aylward at a news conference Thursday. He noted that for the past two weeks there have been only nine new cases confirmed there.

"They [Sierra Leone] are down to numbers where they can drive this to zero," Aylward said.

Another hopeful sign is that a large share of new infections — nearly 70 percent — are occurring in people whom health officials had already been tracking because they were known to have been in contact with an Ebola patient. That's important because it suggests health officials are doing a good job of identifying potential transmission chains.

But Aylward also warned that the campaign to end Ebola in Guinea is proving more "bumpy" than it is in Liberia and Sierra Leone. And he's worried that the progress across West Africa has created a false impression that the battle to stop Ebola has been won. "This is not done," he said. "Success is not assured," he added.

Recently, the U.S. effort in Liberia has come under fire. The multimillion dollar effort to build Ebola treatment units was completed too late to be of much use, The New York Times reported Sunday. The U.S. deployed almost 3,000 military troops at a cost of hundreds of millions to erect 11 treatment facilities. But by the time they were ready, the caseload in Liberia had already fallen precipitously. Only 28 Ebola patients were treated at a unit built by U.S. forces.

Nonetheless, Aylward said, the U.S. promise to build these centers provided an important morale boost for Liberians at the height of the crisis. The U.S. also gave material support and air transport, which was instrumental in getting health worker teams to hard-to-reach hot spots, he said.

Finally, Aylward noted that when the U.S. committed to building the treatment units, statistical models were suggesting infections would continue to rise exponentially in the coming weeks and months.

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