Healthcare workers’ freedom of movement during pandemics is essential under international law to ensure that individuals have access to adequate healthcare. The ability of healthcare workers to move freely across borders in times of pandemics allows for the sharing of knowledge and expertise, as well as the ability to provide healthcare in areas where it is needed most [29]. This can strengthen health systems by providing access to specialized care and increasing the capacity of healthcare providers to respond to outbreaks and other health crises.

Moreover, healthcare workers’ mobility is also a human rights issue. The right to health is recognized as a fundamental human right by the United Nations and is enshrined in the International Covenant on Economic, Social, and Cultural Rights. Access to healthcare is essential for the realization of this right, and healthcare workers’ mobility plays a critical role in ensuring that individuals have access to the care they need [30].

Additionally, healthcare workers’ mobility is an international cooperation issue. The WHO has recognized that the movement of healthcare workers is essential for the provision of healthcare services and that countries need to cooperate in order to ensure that healthcare workers are able to move freely across borders [8]. The WHO has also called for the removal of barriers to the movement of healthcare workers in order to facilitate the recruitment and deployment of healthcare professionals [31].

To strengthen healthcare systems during pandemics, it is important for governments to facilitate the movement of healthcare workers across borders. This can be done through the development of bilateral agreements between countries or through the establishment of regional mechanisms for the movement of healthcare workers during pandemics. International organizations, such as the WHO, can play a critical role in facilitating the movement of healthcare workers across borders. The WHO can provide technical assistance to countries to help them develop policies and programs to facilitate the movement of healthcare workers. Additionally, the WHO can work to build the capacity of healthcare workers through the provision of training and education programs.

To be sure, debates around healthcare workers mobility need to account for the “pervasive inequity in health workers distribution” and the threat it poses to the achievement of universal health coverage [7]. The global healthcare workforce faces a dynamic scenario where countries with low healthcare worker ratios often experience a significant drain of their staff to high-income countries, enticed by the promise of better salaries and living standards. This phenomenon, ultimately, amplifies existing disparities and inequities in healthcare access and quality. Nonetheless, while equity concerns persist in the broader context of healthcare workers mobility, the mobility observed during the COVID-19 pandemic presented a distinct situation. The mobility of healthcare workers during the pandemic was, based on our research, by and large, limited in scope. It was a short-term response to an immediate crisis, with the primary objective of providing critical care during the height of the pandemics. These movements were not driven by the pursuit of better salaries or living conditions but rather by a global commitment to combat the pandemic and save lives. Importantly, these healthcare workers were not granted long-term visas or residency in the countries they were supporting. Their presence was temporary, aligned with the acute phase of the pandemic. This approach, while reflecting the urgency of the situation, also ensured that healthcare workers mobility did not contribute to the traditional equity concerns associated with healthcare workers migration.

Overall, healthcare workers’ freedom of movement during pandemics is essential for ensuring that individuals have access to adequate healthcare, strengthening health systems, and protecting human rights. This conclusion is not only rooted in the imperative need to ensure that individuals can readily access quality healthcare services, but it also aligns seamlessly with the targets set forth in the Sustainable Development Goal 3. SDG 3 compels nations, international organizations, and healthcare professionals to work harmoniously to facilitate the unhindered movement of healthcare workers across borders. This collaboration is not merely an aspiration but an imperative for tackling communicable diseases and fostering well-being for people of all ages. The magnitude of this task extends beyond the confines of a single nation and necessitates the coordinated effort of all stakeholders, including governments, institutions, and the healthcare workforce itself. While Target 3.3 of the SDGs underpins the significance of international collaboration and collective action in promoting health on a global scale to end communicable diseases and promote well-being for all at all ages, Target 3.c focuses on the need to “substantially increase health financing and recruitment, development, training and retention of the health workforce in developing countries”.

Assessing the emergence of a norm of customary international law regarding healthcare workers’ freedom of movement is particularly appealing considering the various obstacles that hinder the adoption or effectiveness of international agreements, including states’ lack of political will and incentives to enter into such agreements. Customary international legal norms are an important source to draw from because once a norm develops, it becomes binding on states unless a state has persistently objected to the norm throughout the process of the norm’s creation [32].

Article 38 of the Statute of the International Court of Justice provides a statement of sources for international law, one of which is customary international law. Norms of customary international law materialize from uniform and consistent state practice taken under a state’s belief that it is compulsory as a matter of international law [32]. The subjective element of a customary international norm, referred to as opinio juris, is both necessary and elusive [33]. Opinio juris precludes a norm from merely developing out of usage as opposed to both usage and a belief, on behalf of a state, that such action is required as a matter of international law [33]. The majority view among scholars is that uniform and consistent state practice will not facilitate the creation of a binding norm if it is so motivated solely by political or economic interests as opposed to opinio juris [33].

It is important to address ways to identify customary international law and its elements—uniform and consistent state practice, as well as opinio juris—in order to detect state practice on the matter of healthcare workers’ freedom of movement. The International Law Commission (“ILC”) 2018 Draft Conclusions on the formation of customary international law (hereinafter “Draft Conclusions”) provide a discussion of each requirement of customary international law [34]. The Draft Conclusions dictate, under Conclusion Four, that the state practice “refers primarily to the practice of states that contributes to the formation or expression of rules of customary international law” [34]. Valid state practice, for purposes of determining the existence of a norm of customary international law, includes “conduct of the state, whether in the exercise of its executive, legislative, judicial or other functions;” “physical and verbal acts” as well as “inaction,” along with “diplomatic acts and correspondence, conduct in connection with resolutions adopted by an international organization or at an intergovernmental conference; conduct in connection with treaties; executive conduct;... legislative and administrative acts; and decisions of national courts” [34]. These forms of practice need be “sufficiently widespread and representative as well as consistent,” but not necessarily universal [34]. The Draft Conclusions expressly note that there is no duration requirement for state practice provided the practice meets the widespread and consistent requirements [34]. Part Four of the Draft Conclusions provides parameters for recognizing evidence of opinio juris, which the Draft Conclusions specify as meaning “[a]ccepted as law” [34]. Opinio juris may be ascertained through the following types of evidence, “public statements made on behalf of States; official publications; government legal opinions; diplomatic correspondence; decisions of national courts; treaty provisions; and conduct in connection with resolutions adopted by an international organization or at an intergovernmental conference” [34]. In accordance with the discussion above, the Draft Conclusions further instruct that while international organizations and intergovernmental conferences cannot create customary international law alone, resolutions adopted by these agencies “may provide evidence for determining the existence and content of a rule of customary international law, and contribute to its development,” and “[a] provision in a resolution adopted by an international organization or at an intergovernmental conference may reflect a rule of customary international law if it is established that the provision corresponds to a general practice that is accepted as law” [34].

Our findings showed that, within months, Argentina, Colombia, Kenya, South Africa, India, Japan, Spain, the United Kingdom, Canada, and the United States, ten nations representing most regions of the world, recognized, as law, the practice of excluding healthcare workers from prohibitions on movement during pandemics.

The findings indicate a strong consensus towards ensuring the free movement of healthcare workers during pandemics. To be sure, discerning opinio juris in connection with the instances of state practice described above is particularly difficult given the fact that the law in this surrounding opinio juris is unsettled. Thus, there is no dispositive answer as to whether the second component of a customary international norm compelling States to ensure healthcare workers’ freedom of movement during pandemics exists. In other words, it is not clear that the state practice on this matter was accompanied by a belief that such action was required as a matter of international law. Arguments can be made in favor of and against this conclusion; it would be imprudent to reach a definitive conclusion in such a short paper. Nonetheless, in general, it appears that evidence weighs in favor of the conclusion that a substantial amount of state practice was in fact taken under a sense of legal obligation or right.