What are the proposed methods for protecting against other sources of bias ? All research personnel will all be blinded to the treatment group except for the study biostatistician, who will be responsible for the randomization computer. Only he will have access to the master file, which can link patient identifiers to the randomization number. This computer will be locked away in a secure space at the James Hogg iCAPTURE Centre in SPH and will have a password protection that only he (or his designate) can access. The study medications and placebo will be packaged and delivered identically as a diskus.