It is absolutely necessary that all students travelling abroad should have extended health travel insurance or health insurance coverage in their own country (i.e. students returning to their home countries for a co-op work term). Your provincial health care is not enough to cover emergencies that could happen while you are abroad.
Coverage can be through your existing health insurance provider. It is important that you read through your policy in order to be aware of what is included (i.e. most insurance policies will not cover high-risk activities such as sky diving, scuba diving, etc). Ensure that your insurance has all the services that you will need including access to multilingual staff, medical evacuation to Canada or the nearest location, a medical escort and emergency dental care, etc. Also, remember to bring a copy of your health insurance contract and policy number with you. Talk to your insurance provider about additional insurance that you might need.