FASTER, PLEASE: For Vaccines Needed in an Epidemic, Timing is Everything.

Last year, scientists launched a trial of an experimental vaccine against Ebola in Guinea. On Friday, they reported great news: The vaccine works well, providing remarkable protection just 10 days after injection.

“We have to stop and celebrate the fact that an innovative trial design was able to come up, in the middle of an emergency, with pretty strong results,” said Dr. Seth Berkley, the chief executive officer of Gavi, an alliance of public and private organizations that provides greater access to vaccines in developing countries. “Let’s start with that.”

But let’s not end with that.

Dr. Berkley and other vaccine experts note a grim irony. Scientists showed that this vaccine was effective in monkeys a decade ago. Thereafter, the vaccine lingered in scientific limbo.

“We should have had an Ebola vaccine at least two or three years ago,” said Dr. Peter J. Hotez, the president of the Sabin Vaccine Institute and a science envoy at the State Department.

Only after the West African outbreak exploded last year did fresh urgency push experimental Ebola vaccines into trials. By the time the positive results were published, the outbreak was subsiding.

“After considerable rush and expense, and after thousands of people have died, you now have a vaccine that appears to be pretty damn good,” said Dr. Stanley A. Plotkin, an emeritus professor of pediatrics at the University of Pennsylvania and a member of the board of the Foundation for Vaccine Research.

We can only guess how many lives might have been saved if this vaccine had passed muster before the outbreak, rather than after.

Years ago, I talked with Bill Frist about his desire to have the ability to develop vaccines really quickly. Failing that, you can just start earlier, I guess.