What leads you to this conclusion?
edit: Allow me to rephrase that. How effective do you think a vaccine will be against a RNA virus? Even the flu vaccine is only effective between 50%-80% (depending on sources and the year) of the strains it has been engineered to defeat. Ebola will never be eradicated like Small Pox, no vaccine will ever defeat it as we must defeat it at the source.
It depends on what mutates and if there are accessible conserved regions to the genome or proteins that are necessary for Ebola to function that can't be mutated, or the virus won't be viable anymore. My understanding is that, while Ebola mutates a lot, there are still conserved things to go after. We will get indications if either of the two leading candidates is effective probably within 6-12 months. They are already starting to pass Phase 1 human-safety tests. Next is to keep vaccinating people and do statistics on how many of them vs. unvaccinated people end up getting Ebola.
There might be a universal vaccine for flu one day, too. Currently, folks go after hemagglutinin, which is highly variable, but accessible. Folks could instead perhaps go for regions that are more conserved or perhaps conserved proteins on the surface of infected cells.
