A recent meta-analysis, which included all studies on interferon-beta (INF-β) in MS [34], showed increased headache incidence over placebo in patients receiving INF-β (Relative Risk 1.16 [95% Confidence Interval 1.02–1.33], p-value = 0.02), who have reported de novo headaches, the aggravation of pre-existing headaches or change in the clinical features. Here, IFNB1 is linked to Headache.