A NEW STUDY ON INITIAL EBV INFECTION AND MS
Ascherio et al. Primary EBV infection and MS. Ann Neurol 2010; in press.
"In this study all EBV-negative subjects (10 out of 10) who developed MS became EBV positive before MS onset. In contrast, only 36% (10 of the 28) controls subjects who were EBV-negative became EBV-positive with follow-up. Ascherio and colleagues conclude that MS risk is extremely low among individuals not infected with EBV, but it increases sharply in the same individuals following EBV infection."
Interpretation: This study is very important with regard to pinning down whether or not EBV causes MS. It ticks one of the criteria for causation; i.e. the correct temporal sequence. You need to get infected with EBV prior to MS onset.