This same observation has already been made in the case of social pensions and has also emerged clearly from a number of national health service systems.24 The issue is not exclusively one of public provision of insurance, but of missing insurance markets. Informal workers who cannot access social security systems unless they subsidise their employers by contributing as self-employed - something that very few of them do - have no option but a private health insurance that rarely caters to their needs. Social protection systems provide the means for societies to eliminate certain forms of social exclusion and to limit downward social mobility.