The cause of the problem was not 'immediately' clear. [=is was not known right away]
They live in the house 'immediately' [='directly'] behind this one.
We need to leave 'immediately'. [='at once', 'right away']
(..) to all corners of the globe. The question that we have got to address is what the hell is it? About % of the population aren't affected immediately. It is viral. it has to be viral. There is no plausible alternative. And like any virus, once we find its origin, we can develop a vaccine. (..)2013 World War Z