OBJECTIVE: To analyze the association of a previous history of varicella virus infection with multiple sclerosis (MS) and its subtypes. MATERIAL AND METHODS: We performed a case-control study including 126 cases and 157 controls. Subjects were divided into subgroups according to MS subtype and the history of varicella virus infection along with other variables was assessed. RESULTS: History of varicella zoster virus (VZV) infection was positive in 42% of controls and 66% of MS cases (p<or=0.001). Patients with a history of VZV infection had a threefold risk increase of having MS. Regarding MS subtypes, relapsing-remitting (RR) MS had four times the risk and secondary progressive had a threefold increase in risk when compared with control patients. CONCLUSIONS: An association between varicella infection history and MS was found, particularly in the RR subtype.
OBJECTIVE: To analyze the association of a previous history of varicella virus infection with multiple sclerosis (MS) and its subtypes. MATERIAL AND METHODS: We performed a case-control study including 126 cases and 157 controls. Subjects were divided into subgroups according to MS subtype and the history of varicella virus infection along with other variables was assessed. RESULTS: History of varicella zoster virus (VZV) infection was positive in 42% of controls and 66% of MS cases (p<or=0.001). Patients with a history of VZV infection had a threefold risk increase of having MS. Regarding MS subtypes, relapsing-remitting (RR) MS had four times the risk and secondary progressive had a threefold increase in risk when compared with control patients. CONCLUSIONS: An association between varicella infection history and MS was found, particularly in the RR subtype.