2nd new rat

Question
I bought another rat last week to put with the one I bought a couple of weeks ago.  The new one doesn't sneeze at all.  Is the new one likely to start sneezing too when I put them together?

Answer
It depends why the other rat is sneezing.
If its from the environment, the other rat may not have any problems with it such as the choice of bedding etc...
If the other rat has an active infection, that still doesnt mean the new rat would catch it.

If it is because the other rat has high levels of histamines that cause sneezing during excitement, the second rat may be more relaxed and not react that way, so its hard to know how the second rat will act since there are various reasons why baby rats sneeze other than illness.