You've got to hand it to the writers, they do a killer job with the science on this show.
Essentially, The Strain Season 2 Episode 2 focused on Eph and Nora's clinical trials. While it was agonizing to watch the McGeevers suffer through their transformation, there was a light at the end of the tunnel. It appears the virus worked.
What happens next though? I mean, if Eph and Nora discovered their strigoi-killer in the second episode, the Master doesn't stand a chance. Something has to go wrong, otherwise the season's over before it began.