“Covid-19 vaccines must be considered a global public good. No country can overcome this crisis in isolation.” So said UN Secretary General Antonio Guterres.  Many other world leaders and organisations have used similar language. 
Everyone agrees worldwide access to vaccines, regardless of wealth or geography, is an ethical imperative. The language of global public goods may seem to express this commitment. But describing covid-19 vaccines as global public goods is inaccurate and counterproductive to achieving the crucial goal of vaccinating everyone in the world.
Humpty Dumpty was wrong when he said, “When I use a word, it means just what I choose it to mean—neither more nor less.”  As Alice makes clear, for words to accurately communicate ideas between people, they must adhere to common, accepted meanings—not the private meanings of the speaker.
What do the words “global public good” mean? The concept of public goods goes back at least to the mid 20th century and the work of Richard Musgrave and Paul Samuelson.  A public good must satisfy two criteria: non-rivalry and non-excludability. A good is nonrival when one individual’s enjoyment of that good—for instance, of a pleasant outdoor temperature—does not interfere with another person’s enjoying it. Conversely, food, say a bowl of soup, is rival because once one person has consumed it, another cannot. A good is nonexcludable if excluding individuals from enjoying it is impossible. Pleasant outdoor temperatures are both nonexcludable and nonrival. Importantly, nonexcludability is distinct from nonexclusion. Even though a food bank may choose to provide food to all comers, food—including at food banks—remains an excludable good.
A livable global temperature is a paradigmatic public good. It is nonrival— one person’s enjoying a livable climate does not affect others doing so—and nonexcludable—no-one can practicably be prevented from experiencing the advantages of a livable climate.
Worldwide vaccination against covid-19, worldwide access to healthy food, and livable global temperatures are all ethically worthy aims. But, as Gavi, the Vaccine Alliance, notes, like food and unlike livable global temperatures, covid-19 vaccines are not—and cannot be—global public goods.  Worldwide eradication of covid-19 would be a global public good. Covid-19 vaccines, in contrast, are rival. A vaccine dose given to one person cannot simultaneously go to another. Likewise, vaccines are excludable: a country can decide—as some have—to vaccinate only citizens and residents. That Gavi has laudably worked for childhood vaccines, to ensure that “vaccination would be available to anyone who needs it” does not render vaccines public goods. Instead, Gavi ensures universal access to a rival, excludable good.
Describing covid-19 vaccines as global public goods diverts attention from the real challenges of achieving universal vaccination. If a covid-19 vaccine really were a global public good, global attention would focus only on maximal production of vaccines, not their fair distribution. Because global public goods are nonexcludable, one country’s contribution to global public goods, for instance by reducing carbon emissions, automatically spill across borders without the need for organisations to intentionally distribute the fruits of those actions. Instead, for public goods, the challenge is production. People and countries hope to free ride on others’ good work. Hence, public goods tend to be underproduced. All the attention focused on the fair distribution of available covid-19 vaccine among countries confirms that they are not global public goods.
Rather than being global public goods, covid-19 vaccines are best understood as a humanitarian entitlement, or as the object of a positive right. This focuses our attention on the critical issues of optimizing production and the fair distribution of a covid-19 vaccine. Covid-19 vaccines do not cross borders or directly benefit the people most in need without intentional efforts to distribute them fairly. Like public goods, vaccines have positive externalities, and so will tend in a purely market-based system to be underproduced relative to their benefits. But, unlike public goods, vaccines are rival and excludable; without intentional efforts, they will remain insufficiently accessible to the poor.  Although immunity in one country helps others by reducing the amount of circulating virus globally, vaccines produced or stored in one country can often do far more good abroad. Worldwide vaccine access, requires more than asserting that vaccines are global public goods. Decisionmakers need to overcome externality problems to ensure that more vaccines are actually produced than private willingness to pay would support, and to fairly distribute those vaccines despite the possibility of hoarding and the reality of competition between potential recipients.
An effective global response to the covid-19 pandemic must recognise that vaccine access is an ethical imperative despite vaccines being both rival and excludable. Vaccine access is ethically imperative, hence the need to simultaneously scale up production, distribute available supply fairly, and ensure no vaccine expires because countries are incapable of administering them.
Govind Persad, University of Denver Sturm College of Law.
Ezekiel J. Emanuel, University of Pennsylvania Perelman School of Medicine.
Competing interests: GP reported receiving grants from Greenwall Foundation and personal fees from ASCO Post and the World Health Organization outside the submitted work. EJE reported being a partner at ReCovery Partners, LLC, Oak HC/FT, and Embedded Healthcare, LLC; receiving personal fees from Center for Neurodegenerative Disease Research, Genentech Oncology, Council of Insurance Agents and Brokers, America’s Health Insurance Plans, Montefiore Physician Leadership Academy, Greenwall Foundation, Medical Home Network, Healthcare Financial Management Association, Ecumenical Center–UT Health, American Academy of Optometry, Associação Nacional de Hospitais Privados, National Alliance of Healthcare Purchaser Coalitions, Optum Labs, Massachusetts Association of Health Plans, District of Columbia Hospital Association, Washington University, Brown University, McKay Lab, American Society for Surgery of the Hand, Association of American Medical Colleges, America’s Essential Hospitals, Johns Hopkins University, National Resident Matching Program, Shore Memorial Health System, Tulane University, Oregon Health & Science University, United Health Group, CBI, and Blue Cross Blue Shield; and receiving nonfinancial support (travel reimbursement) from the Center for Global Development, The Atlantic, RAND Corporation, and Goldman Sachs outside the submitted work.
1. COVID-19 Vaccines Must be Global Public Good, Secretary-General Says, Announcing ‘Only Together’ Campaign to Encourage Sharing of Technology, Doses. New York: United Nations, 2021 (https://www.un.org/press/en/2021/sgsm20620.doc.htm).
2. Moon S, Alonso Ruiz A, Vieira M. Averting Future Vaccine Injustice. New England Journal of Medicine. 2021 Jul 10.
3. Carroll L. Through the Looking-Glass and What Alice Found There. Chapter 6. Chicago, IL: W.B. Conkey Co., 1900.
4. Sekera J. A Brief History of Public Goods [Internet]. New York (USA): Demos; 2013 Nov 6 [cited 2021 Jun 10]. Available from: https://www.demos.org/blog/brief-history-public-goods
5. Are vaccines a global public good? Geneva: Gavi, the Vaccine Alliance, 2020 (https://www.gavi.org/vaccineswork/are-vaccines-global-public-good).
6. Helbing T. Externalities: Prices Do Not Capture All Costs [Internet]. Washington, D.C. (USA): International Monetary Fund; 2020 Feb 24 [cited 2021 Jun 10]. Available from: https://www.imf.org/external/pubs/ft/fandd/basics/external.htm