Disappointment, but no despair, at least not yet. That’s how researchers at various institutions try to come off as they discuss the recent end to Merck’s efforts to develop an HIV vaccine. And so they’re displaying a collective stiff upper lip. Here’s what a few told The Philadelphia Inquirer…

“I must admit I was shocked when I saw the outcome. It was the most promising vaccine we had,” says Hildegund C.J. Ertl, an immunologist at The Wistar Institute in Philadelphia who is preparing to test another HIV vaccine. (That’s Ertl in the middle).

“To paraphrase some of my colleagues, the trial shows a failure of a specific product but not a failure of the concept,” says Gary Nabel, director of the Vaccine Research Center of the National Institutes of Health, who is also involved in another HIV vaccine trial. But “it would be truly remarkable” to develop a vaccine in less than 10 years.

“The information is going to help us develop vaccine in the future,” Ian Frank, director of the HIV Vaccine Trials Unit at the University of Pennsylvania, which enrolled 125 women into the Merck trial and will be testing two other vaccines, tells the paper. “I don’t think people should be overly disappointed. We’re really at the very earliest stages in this process.”

“We now have a line in the sand. We need to do better than” the Merck trial, says Dave Weiner, a Penn pathology professor whose group has been a leader in using DNA to stimulate an immune response against HIV. “We should be testing different hypotheses so when they fail, we can refocus on things that have a better chance of working.”

John Shiver, who heads Merck’s basic research in vaccines and who’s credited with several research advances, says he didn’t think any current approach would work. He said he thought a new burst of creativity was needed. “It’s a virus of change. It’s different in every person. That makes making an HIV vaccine a huge challenge.”