While the effectiveness of a treatment is very important, no one wants to deal with side-effects that greatly impact their quality of life. We asked patients about the severity of side-effects with interferon and non-interferon treatments.

Fortunately, severe side-effects were rare for both groups. However, interferons appear to cause many more "moderate" and "mild" side-effects that do non-interferon based alternatives. Indeed, more than 60% of patients using interferons had some kind of adverse reaction. For non-interferons, the incidence of side-effects was much lower, with less than 4 in 10 people reporting side-effects. Notably, there was a higher degree of uncertainty with non-interferon treatments, with more than 1 in 4 patients being unsure whether they treatments caused side-effects.