I was on Humira for almost 5 years (now switching to Cosentyx, since Humira put me in the hospital twice in 4 months with respiratory infections.) Yes, the main side effect I had when starting Humira was extreme fatigue...for a couple of months. Eventually, there were no symptoms or side effects at all....until this last year, when Humira “went rogue” and did its job too well...pushing my immunosuppression to a lower level than desired. I took a 4.5 month break, had a PsA flare at 2 months and went on Prednisone. I took my first Cosentyx shot (150mg x 1monthly) yesterday, and hope it will work for me!