Impact of the Modifications of Environmental Exposures and Health Care Access During COVID-19 Lockdown on Multiple Sclerosis

"Each included patient will be given a paper questionnaire, with the following questions:~* Zip code of patient's iterative residences since 2018, as well as the zip code of residence at the time of the 2 confinements~* Occupational status~* Occurrence of COVID infection/date needed for hospitalization~* During the COVID-19 outbreak, did the patient: avoid seeing a doctor, avoid going to health care facilities, stop background treatment for MS. If yes to any of the questions, the reason, date and duration of the cessation will be asked.~Other sources of data will be used together:~Clinical data from the OFSEP registry Pollution data from approved air quality monitoring associations Data on the circulation of influenza and gastroenteritis, produced by Santé Publique France"