Universal health care, (also referred to as universal health coverage, universal coverage, universal care or socialized health care) usually refers to a health care system that provides health care and financial protection to all citizens of a particular country. It is organized around providing a specified package of benefits to all members of a society with the end goal of providing financial risk protection, improved access to health services, and improved health outcomes.  Universal health care is not one-size-fits-all and does not imply coverage for all people for everything. Universal health care can be determined by three critical dimensions: who is covered, what services are covered, and how much of the cost is covered.  It is described by the World Health Organization as a situation where citizens can access health services without incurring financial hardship.  U.N. member states have agreed to work toward worldwide universal health coverage by 2030. 
The first move towards a national health insurance system was launched in Germany in 1883, with the Sickness Insurance Law. Industrial employers were mandated to provide injury and illness insurance for their low-wage workers, and the system was funded and administered by employees and employers through "sick funds", which were drawn from deductions in workers' wages and from employers' contributions. Other countries soon began to follow suit. In the United Kingdom, the National Insurance Act 1911 provided coverage for primary care (but not specialist or hospital care) for wage earners, covering about one third of the population. The Russian Empire established a similar system in 1912, and other industrialized countries began following suit. By the 1930s, similar systems existed in virtually all of Western and Central Europe. Japan introduced an employee health insurance law in 1927, expanding further upon it in 1935 and 1940. Following the Russian Revolution of 1917, the Soviet Union established a fully public and centralized health care system in 1920.  However, it was not a truly universal system at that point, as rural residents were not covered.
In New Zealand, a universal health care system was created in a series of steps, from 1939 to 1941.   In Australia, the state of Queensland introduced a free public hospital system in the 1940s.
Following World War II, universal health care systems began to be set up around the world. On July 5, 1948, the United Kingdom launched its universal National Health Service. Universal health care was next introduced in the Nordic countries of Sweden (1955), Iceland (1956),  Norway (1956),  Denmark (1961),  and Finland (1964).  Universal health insurance was then introduced in Japan (1961), and in Canada through stages, starting with the province of Saskatchewan in 1962, followed by the rest of Canada from 1968 to 1972.   The Soviet Union extended universal health care to its rural residents in 1969.   Italy introduced its Servizio Sanitario Nazionale (National Health Service) in 1978. Universal health insurance was implemented in Australia beginning with the Medibank system in 1975, which led to universal coverage under the Medicare system, established in 1984.
From the 1970s to the 2000s, Southern and Western European countries began introducing universal coverage, most of them building upon previous health insurance programs to cover the whole population. For example, France built upon its 1928 national health insurance system, with subsequent legislation covering a larger and larger percentage of the population, until the remaining 1% of the population that was uninsured received coverage in 2000.   In addition, universal health coverage was introduced in some Asian countries, including South Korea (1989), Taiwan (1995), Israel (1995), and Thailand (2001).
Beyond the 1990s, many countries in Latin America, the Caribbean, Africa, and the Asia-Pacific region, including developing countries, took steps to bring their populations under universal health coverage, including China which has the largest universal health care system in the world.  A 2012 study examined progress being made by these countries, focusing on nine in particular: Ghana, Rwanda, Nigeria, Mali, Kenya, India, Indonesia, the Philippines, and Vietnam.  
Universal health care in most countries has been achieved by a mixed model of funding. General taxation revenue is the primary source of funding, but in many countries it is supplemented by specific levies (which may be charged to the individual and/or an employer) or with the option of private payments (by direct or optional insurance) for services beyond those covered by the public system.
Almost all European systems are financed through a mix of public and private contributions.  Most universal health care systems are funded primarily by tax revenue (like in Portugal  Spain, Denmark, and Sweden). Some nations, such as Germany and France  and Japan  employ a multipayer system in which health care is funded by private and public contributions. However, much of the non-government funding is by contributions by employers and employees to regulated non-profit sickness funds. Contributions are compulsory and defined according to law.
A distinction is also made between municipal and national healthcare funding. For example, one model is that the bulk of the healthcare is funded by the municipality, speciality healthcare is provided and possibly funded by a larger entity, such as a municipal co-operation board or the state, and the medications are paid by a state agency.
This is usually enforced via legislation requiring residents to purchase insurance, but sometimes the government provides the insurance. Sometimes, there may be a choice of multiple public and private funds providing a standard service (as in Germany) or sometimes just a single public fund (as in Canada). Healthcare in Switzerland and the US Patient Protection and Affordable Care Act are based on compulsory insurance. 
In some European countries in which private insurance and universal health care coexist, such as Germany, Belgium, and the Netherlands, the problem of adverse selection is overcome by using a risk compensation pool to equalize, as far as possible, the risks between funds. Thus, a fund with a predominantly healthy, younger population has to pay into a compensation pool and a fund with an older and predominantly less healthy population would receive funds from the pool. In this way, sickness funds compete on price, and there is no advantage to eliminate people with higher risks because they are compensated for by means of risk-adjusted capitation payments. Funds are not allowed to pick and choose their policyholders or deny coverage, but they compete mainly on price and service. In some countries, the basic coverage level is set by the government and cannot be modified. 
The Republic of Ireland at one time had a "community rating" system by VHI, effectively a single-payer or common risk pool. The government later opened VHI to competition but without a compensation pool. That resulted in foreign insurance companies entering the Irish market and offering cheap health insurance to relatively healthy segments of the market, which then made higher profits at VHI's expense. The government later reintroduced community rating by a pooling arrangement and at least one main major insurance company, BUPA, then withdrew from the Irish market.
Among the potential solutions posited by economists are single-payer systems as well as other methods of ensuring that health insurance is universal, such as by requiring all citizens to purchase insurance or limiting the ability of insurance companies to deny insurance to individuals or vary price between individuals.  
Single-payer health care is a system in which the government, rather than private insurers, pays for all health care costs.  Single-payer systems may contract for healthcare services from private organizations (as is the case in Canada) or own and employ healthcare resources and personnel (as was the case in England before of the Health and Social Care Act). "Single-payer" thus describes only the funding mechanism and refers to health care financed by a single public body from a single fund and does not specify the type of delivery or for whom doctors work. Although the fund holder is usually the state, some forms of single-payer use a mixed public-private system.
In tax-based financing, individuals contribute to the provision of health services through various taxes. These are typically pooled across the whole population, unless local governments raise and retain tax revenues. Some countries (notably the United Kingdom, Canada, Ireland, Australia, New Zealand, Italy, Spain, Portugal and the Nordic countries) choose to fund health care directly from taxation alone. Other countries with insurance-based systems effectively meet the cost of insuring those unable to insure themselves via social security arrangements funded from taxation, either by directly paying their medical bills or by paying for insurance premiums for those affected.
Social health insurance
In social health insurance, contributions from workers, the self-employed, enterprises and government are pooled into a single or multiple funds on a compulsory basis. It is based on risk pooling.  The social health insurance model is also referred to as the 'Bismarck Model,' after Prussian Chancellor Otto von Bismarck, who introduced the first universal health care system in Germany in the 19th century.  The funds typically contract with a mix of public and private providers for the provision of a specified benefit package. Preventive and public health care may be provided by these funds or responsibility kept solely by the Ministry of Health. Within social health insurance, a number of functions may be executed by parastatal or non-governmental sickness funds or in a few cases by private health insurance companies. Social health insurance is used in a number of Western European countries and increasingly in Eastern Europe as well, as well as in Israel and Japan. 
In private health insurance, premiums are paid directly from employers, associations, individuals and families to insurance companies, which pool risks across their membership base. Private insurance includes policies sold by commercial for profit firms, non-profit companies, and community health insurers. Generally, private insurance is voluntary in contrast to social insurance programs, which tend to be compulsory. 
In some countries with universal coverage, private insurance often excludes many health conditions that are expensive and the state health care system can provide. For example, in the United Kingdom, one of the largest private health care providers is BUPA, which has a long list of general exclusions even in its highest coverage policy,  most of which are routinely provided by the National Health Service. In the United States, dialysis treatment for end stage renal failure is generally paid for by government, not by the insurance industry. Those with privatized Medicare (Medicare Advantage) are the exception and must get their dialysis paid through their insurance company, but those with end stage renal failure generally cannot buy Medicare Advantage plans. 
The Planning Commission of India has also suggested that the country should embrace insurance to achieve universal health coverage.  General tax revenue is currently used to meet the essential health requirements of all people.
Community-based health insurance
A particular form of private health insurance that has often emerged if financial risk protection mechanisms have only a limited impact is community-based health insurance. Individual members of a specific community pay to a collective health fund, which they can draw from when they need of medical care. Contributions are not risk-related, and there is generally a high level of community involvement in the running of these plans.
Implementation and comparisons
Universal health care systems vary according to the degree of government involvement in providing care and/or health insurance. In some countries, such as the UK, Spain, Italy, Australia and the Nordic countries, the government has a high degree of involvement in the commissioning or delivery of health care services and access is based on residence rights, not on the purchase of insurance. Others have a much more pluralistic delivery system, based on obligatory health with contributory insurance rates related to salaries or income and usually funded by employers and beneficiaries jointly.
Sometimes, the health funds are derived from a mixture of insurance premiums, salary related mandatory contributions by employees and/or employers to regulated sickness funds, and by government taxes. These insurance based systems tend to reimburse private or public medical providers, often at heavily regulated rates, through mutual or publicly owned medical insurers. A few countries, such as the Netherlands and Switzerland, operate via privately owned but heavily regulated private insurers, which are not allowed to make a profit from the mandatory element of insurance but can profit by selling supplemental insurance.
Universal health care is a broad concept that has been implemented in several ways. The common denominator for all such programs is some form of government action aimed at extending access to health care as widely as possible and setting minimum standards. Most implement universal health care through legislation, regulation and taxation. Legislation and regulation direct what care must be provided, to whom, and on what basis. Usually, some costs are borne by the patient at the time of consumption, but the bulk of costs come from a combination of compulsory insurance and tax revenues. Some programs are paid for entirely out of tax revenues. In others, tax revenues are used either to fund insurance for the very poor or for those needing long-term chronic care.
The United Kingdom National Audit Office in 2003 published an international comparison of ten different health care systems in ten developed countries, nine universal systems against one non-universal system (the United States), and their relative costs and key health outcomes.  A wider international comparison of 16 countries, each with universal health care, was published by the World Health Organization in 2004.  In some cases, government involvement also includes directly managing the health care system, but many countries use mixed public-private systems to deliver universal health care.