If you are a student travelling to Canada  for the first time :   Your medical exam expires 12 months after it is completed. If you do not travel to Canada in the 12-month validity period, you   must have a new medical exam completed   to be able to enter Canada, even if your study permit approval is still valid.   https://travel.gc.ca/travel-co vid/travel-restrictions/answer s/foreign-non-us-student   You are  returning  to Canada and have a valid study permit : If your medical exam (completed in support of your study permit application) is more than 12 months old,  AND  you have lived or travelled for 6 months or more in certain countries or territories before returning to Canada, you must have a new medical exam completed.  You can check which countries will require a new medical exam here:  https://www.canada.ca/en/immig ration-refugees-citizenship/se rvices/application/medical-pol ice/medical-exams/requirements -temporary-...
CANADA IMMIGRATION NEWS AND TIPS