Hello , I can empathise with you on this as I am a severe asthmatic too and tend to get frequent chest infections . Anything and everything can bring on an attack and I am too often on a course of 30-40mg Prednisolone a day plus all the other meds.. I can't think of any advise I have been given regarding our reduced immunity other than avoiding people with colds and things.Not much help to you I am sure , just wanted to let you know that I have that same question :-) xx