The ransomware didn't change too much compared to version 3.0, but it changed enough to cause problems to any detection or prevention systems put out by cyber-security vendors.
One of those systems is Bitdefender's CryptoWall Vaccine, a.k.a. the Bitdefender Anti-Ransomware kit.
Integrating the changes that CryptoWall 4.0 brought forward, the CryptoWall Vaccine can now prevent infections from getting a foothold on target PCs.
As for the CryptoWall Vaccine's efficiency, the name should tell you everything there is to know about it. It's a vaccine, meaning you install it before getting infected, as a way to protect yourself
Read more: http://news.softpedia.com/news/cryptowall-vaccine-updated-for-the-latest-4-0-version-495916.shtml