Yes, that is possible. Why? Immune suppressant drugs suppress antibody production. 4-eyes, you must just be replete with them!
Usually, a steroid inhaler (not nasal but via the mouth) is used. Those nasal inhalers can wreck the nose over time, ironically making seasonal allergies worse.
My steroid inhaler for asthma (which I have due to a bronchial reaction from Mestinon) does help my MG. But it comes with similar side effects as the tablets, just not as pronounced.
I hope you will consider taking flax, fish, or olive oil or eating walnuts for good prostaglandins while on the steroid. Steroids are anti-prostaglandins, and can affect things such as the gel coating of the stomach. And calcium/vitamin D. Many doctors don't talk about how drugs can affect the body!
I hope you will have some answers soon!!

Annie