| Methods |
Case‐control study |
| Participants |
Cases (n = 140): people affected by MS as defined by the International Panel on MS Diagnosis.
Controls (n = 131): sex‐ and age‐matched to the cases. |
| Interventions |
Exposure to influenza vaccination (unspecified). Exposure to many other factors was assessed by means of face‐to‐face structured questionnaires. Time of onset after exposure is probably not mentioned in the text. |
| Outcomes |
Multiple sclerosis |
| Notes |
"The study was supported by a grant of the University of Trieste, Italy: MPI 60%, 2001" |
| Risk of bias |
| Bias |
Authors' judgement |
Support for judgement |
| CC ‐ case selection
All outcomes |
Low risk |
Hospital population |
| CC ‐ control selection
All outcomes |
High risk |
Blood donor population |
| CC ‐ comparability
All outcomes |
High risk |
Poor matching |
| CC ‐ exposure
All outcomes |
High risk |
Interview |
| Summary assessment |
High risk |
High risk |
