If you are leaving your home country, you should always have emergency medical and evacuation coverage.
This coverage is included in all vacation travel insurance plans, or you can buy a travel medical insurance (which does not have cancellation coverage). Click here for more about these types of plans.
When you leave your home country, your health insurance may or may not travel with you. Whenever you are traveling abroad, buy either a travel medical plan or vacation plan that includes medical emergencies.