Table 1 Classification of VHI roles

Primary

Principal: Represents the only available access to health insurance.

In the United States of America, VHI has been the principal source of coverage before 2014 [78].

Substitutive: Substitutes for cover which would otherwise be available from the public health insurance system, but the individual has voluntarily opted out of this or is not entitled to it. In the case of opting out, people do not pay public health insurance contributions.

In Germany and Chile, opt out options from the public health insurance system exist in order to be covered by VHI [3, 47]. Such substitutive VHI often includes additional services and is thus also supplementary in nature.

Complementary

Complements coverage of publicly insured services or services within principal/substitute health insurance, by covering all or part of the residual costs (e.g. co-payments).

France’s complementary VHI primarily serves to reimburse copayments required in the public health insurance system [79].

Community based health insurance schemes in Sub-Saharan Africa usually cover user fees, although they may also represent a form of principal voluntary health insurance.

Supplementary

Covers additional health services not covered by the public scheme; depending on the country this may include for example elective care, long-term care, dental care, pharmaceuticals, rehabilitation, alternative or complementary medicine, superior hotel and amenity hospital services.

In Germany supplementary VHI exists for additional services (e.g. dental care, private hospital room). Similarly supplementary VHI is found in the Russian Federation, Latvia and Hungary [80].

Duplicative

Covers health services already covered under public health insurance, but with access to other, additional providers or levels of service, e.g. private health facilities. However unlike substitutive insurance it does not exempt enrollees from contributing to public health insurance.

In the United Kingdom duplicative VHI exists as an additional alternative to the public system.

Similarly in Nicaragua, wealthy people may purchase VHI that provides access to the private sector and coverage of additional services that are not included in the mandatory public scheme. Yet, they continue paying public health insurance contributions [81].