Originally Posted by Libertine

What makes this news incredible instead of just great is that it's a huge step towards a vaccine with a near-100% effectiveness.

It's comparable to one of the best ways of becoming successful in business: find something that works, then modify it to work even better and scale the hell out of it.

In this case, there is something that appears to work, so the exact mechanism can be studied and hopefully adapted in a way that makes it work for everyone. If this wasn't just a glitch in statistics (and it could be, alas), it means there will almost certainly be a fully effective vaccine in the next few decades.