“a contract between the insured and the insurer to the effect that in the event of specified events (determined in the insurance contract) occurring the insurer will pay compensation either to the insured person or to the health service provider. There are two major forms of health insurance. One is private health insurance, with premiums based on individual or group risks. The other is social security, whereby in principle society’s risks are pooled, with contributions by individuals usually dependent on their capacity to pay.