Multiple sclerosis and varicella zoster virus infection: A review

We have evaluated the epidemiological evidence for an aetiological role of varicella zoster virus (VZV) infection in the development of multiple scler osis (MS). A MEDLINE search of the English language literature for 1965-99 identified 40 studies. These studies were categorized as seroepidemiologica l (13), case-control (23), historical cohort (2) or ecological (2). One stu dy used both case-control and historical cohort methodologies. Studies were then classified according to methodological rigour, using criteria derived from published guidelines for the epidemiological study of MS. There was a large variability in the quality of evidence. The five studies with the be st methodology failed to show an increased risk of MS associated with varic ella or zoster infections. At the present time there is insufficient eviden ce to support an important aetiological role of VZV infection in the develo pment of MS.