One of the biggest challenges of fighting the ongoing Ebola outbreak is that we have no known cure, or treatment, for the disease. When doctors treat Ebola, all they can do is keep the patient's immune system as strong as possible, so that he or she can fight off the vicious infection.

Francis Collins, director of the National Institutes of Health, says it doesn't have to be this way. In an interview with the Huffington Post's Sam Stein, Collins argued that we don't have an Ebola vaccine because of budget cuts at the NIH.

"If we had not gone through our 10-year slide in research support," Collins told Stein, "We probably would have had a vaccine in time for this that would've gone through clinical trials and would have been ready."

But is that true? There are two assumptions embedded in Collins' remarks. One is that Ebola vaccine research has been hurt by National Institute of Health budget cuts. The other is that, without those budget cuts, Ebola was on the fast path to a successful vaccine. Neither of these claims, when you dig into the data, appear to hold up especially well.

Government funding for Ebola research has been steady (and small)

There has no doubt been a slowdown in the National Institute of Health's budget's growth in recent years.

The NIH's budget rose rapidly during the early 2000s, growing from $17 billion in 2000 to a peak of $31 billion in 2010. This meant more money for everything. The budget for the National Institute of Allergy and Infectious Diseases — the unit that researches Ebola — grew from $3.7 billion to $4.7 billion over that time period.

Funding then began to decline in 2010 and has continued to fall slightly over the past four years (this was during a period when Obama was in the White House, Democrats controlled the Senate, and Republicans controlled the House). By 2013, funding was down to $29.3 billion. These figures do not account for inflation.

So how did this affect Ebola research? It's hard to get exact numbers, since the NIH only began reporting information on how much it spent on particular diseases in 2010. But what that data shows is that the NIH has consistently spent a relatively small amount of money on Ebola research since 2010.

At my request, the American Society for Biochemistry and Molecular Biology pulled data from an NIH reporting database on funding for various diseases. They included data on hemorrhagic fevers (essentially Ebola and Marburg) and other infectious diseases, like the flu and malaria. Here's what funding patterns have looked like since 2010:

There was a decline in funding for Ebola research between 2010 and 2011, from $142 million to $101 million, respectively. This was when stimulus funding dollars ran out, and the entire agency had to cut back. Since 2011, funding has been small and slightly declining: research for Ebola and Marburg received $101 million in grants in 2011, $100 million in 2012 and $96 million in 2013, after the sequester took effect.

In fact, the cuts to Ebola research have been less severe than cuts for research on other diseases. The numbers show that Ebola research funding fell 4 percent between 2012 and 2013. During the same time frame, malaria funding fell by 7 percent — and overall NIAID dollars dropped by 5.5 percent.

Vaccine research is unpredictable

NIH funding definitely matters. "It's fair to say that, without the budget cuts, we would be closer to a cure than we are right now," says Benjamin Corb at the American Society for Biochemistry and Molecular Biology. "We would have understood the virus and perhaps understood how to counteract the virus if we didn't have budget cuts."

But as Corb pointed out to me, there's a long space between being closer to a vaccine — and "probably" having one (which is what Collins claimed).

Drug research is incredibly unpredictable. Building any vaccine is a long, tedious job typically marked with failure. From the lab to the pharmacy, a typical drug takes about 12 years to build. Of the 5,000 different compounds that drug companies experiment with, five typically make it to human tests — and one gets approved for sale.

Most drugs do not survive this process, and it's incredibly hard to know whether the candidate Ebola vaccines would be winners or losers. Drug manufacturers can only find this out when they go into trials. They find out if the treatments that work well in animal models are safe and effective in humans.

There have been a handful of Ebola vaccine trials that began in 2003; none of them have thus far made it past phase 1, although the NIH does say the information learned in early trials has helped inform further drug development.

The part of Collins' statement that irks scientists is the sense of certainty, the idea that if only more money had been spent, we'd likely have a vaccine by now. They know that's not how vaccine development works. Scientists don't get to name a price for the development of a vaccine — the science is just too uncertain.

scientists don't get to name the price tag of finding a vaccine. research is too uncertain.

The NIH is not the only player necessary to take vaccines to market. The agency's role in pharmaceutical development is usually basic research, giving scientists grants to look at how diseases function and what can stop them.

When it's time to use that science to build a vaccine, that's where drug companies typically come in, paying for the trials and manufacturing. We don't know whether, in a world where the NIH had more funding, a pharmaceutical company would have stepped forward to do this. There's decent reason to believe there wouldn't have been; a vaccine to treat Ebola, an infrequent disease that hits low-income areas of the world, is hardly a blockbuster.

It's possible that, in the wake of this Ebola outbreak, the United States decides to put more money towards Ebola research. But that extra funding will not be a guarantee that a vaccine is right around the corner. That just isn't how drug research works.