The Swine Flu Outbreak and International Law

David P. Fidler
April 27, 2009

A new swine influenza virus is causing outbreaks in humans in Mexico, the United States, and Canada, and the virus has possibly spread to other countries. This outbreak has alarmed public health officials because of its epidemiological characteristics, which indicate that the virus may be able to cause a pandemic. Efforts to prepare for pandemic influenza have been underway following the emergence of a dangerous strain of avian influenza in 2004.[1] The outbreak is testing these preparations, including new rules of international law the International Health Regulations 2005 (IHR 2005) adopted by the World Health Organization (WHO).[2] This Insight provides information on the outbreak and discusses the IHR 2005's role in the responses to it.

Information on the Swine Flu Outbreak

According to WHO, swine flu "is a highly contagious acute respiratory disease of pigs, caused by one of several swine influenza A viruses."[3] Although humans have contracted swine flu from pigs in the past, the strain causing the recent outbreak of €”swine influenza A (H1N1) €”is novel. This strain causes concern because it €œis substantially different from human influenza A (H1N1) viruses, [meaning] that a large proportion of the population might be susceptible to infection, and that the seasonal influenza vaccine H1N1 strain might not provide protection.€[4]

This strain of swine influenza has been identified in confirmed cases in 19 of Mexico's 32 states (18 total confirmed cases, as of April 26, 2009),[5] the United States (20 confirmed cases in five states, as of April 26, 2009),[6] and Canada (6 confirmed cases in 2 Canadian provinces, as of April 26, 2009).[7]

Potential cases in Mexico may, however, be higher because Mexico reported, as of April 23, 2009, over 800 cases of influenza-like illness with 59 deaths.[8] By April 26, 2009, the press reported that over 1,300 cases and 81 deaths had occurred in Mexico.[9] The outbreak's severity caused the Mexican government to exercise emergency powers, under which it has banned public gatherings and closed schools to slow the virus' spread. The World Bank has already extended $205 million in loans to help Mexico deal with the outbreak.[10]

News reports on April 26, 2009, also indicated that possible cases had been identified in Australia, France, Hong Kong, Israel, New Zealand, and Spain.[11] The actual and possible appearance of this new virus in multiple locations in Mexico, the United States, and Canada and in North America, Europe, and Asia indicated that geographical containment of the virus is not possible.

More worries have arisen because the virus in Mexico is linked with mortality in young and otherwise healthy adults, which is not the population cohort that typically experiences death when exposed to seasonal influenza viruses.[12] The susceptibility of young, healthy adults has brought about comparisons to the pandemic of 1918-19, that killed millions of healthy, young adults around the world.[13] Fortunately, the swine flu strain is, at the moment, sensitive to the anti-viral drugs oseltamivir and zanamivir.[14]

The cases in the United States have, to date, only produced mild illness, one hospitalization, and no deaths. Nevertheless, the geographical pattern of morbidity in the United States, combined with the outbreak in Mexico and the virus' apparent global spread, prompted the United States to declare a public health emergency on April 26, 2009.[15]

The different impact of the same virus in Mexico and in the United States is only one of many unanswered questions public health officials and scientists have about this new virus. In the coming days, WHO will lead a global epidemiological and scientific effort to answer questions this new virus and outbreak raise.[16]

The Swine Flu Outbreak and the International Health Regulations 2005

In response to the outbreak, WHO has applied the IHR 2005, which the World Health Assembly adopted in 2005 and which entered into force in 2007.[17] The IHR 2005 was the product of a ten-year effort to revise the international rules on infectious diseases[18] and represents a radical transformation of these rules in an attempt to build a stronger framework for cooperation against disease threats.[19] The swine flu outbreak constitutes a major test on how well WHO and its member states apply the IHR 2005 to a dangerous outbreak.[20]

Declaration of a Public Health Emergency of International Concern

On April 25, 2009, the WHO Director-General convened an Emergency Committee and, based on its advice, declared that the outbreak constituted a "€œpublic health emergency of international concern"€ under the IHR 2005.[21] The swine flu outbreak marks the first time under the IHR 2005 that the Director-General convened the Emergency Committee and determined that a public health emergency of international concern exists.

The IHR 2005 authorizes the WHO Director-General to make such a declaration (Article 12(1)), and the IHR 2005 defines a public health emergency of international concern as "€œan extraordinary event which is determined . . . (i) to constitute a public health risk to other States through the international spread of disease and (ii) to potentially require a coordinated international response"€ (Article 1). At the request of the Director-General, the Emergency Committee provides its views on whether an event constitutes a public health emergency of international concern (Article 48(1)(a)).[22]

The Emergency Committee did not advise the WHO Director-General to raise the pandemic alert level from Phase 3 to Phase 4.[23] As part of preparing for pandemic influenza, WHO developed phases for pandemic influenza (see box), and the Director-General can change the alert level based on the threat from an influenza outbreak. The Emergency Committee may recommend moving the pandemic alert level to Phase 4 as early as April 28, 2009, depending on its review of new information.


Phase Description
1 No new influenza virus subtypes have been detected in humans. An influenza virus subtype that has caused human infection may be present in animals. If present in animals, the risk of human infection or disease is considered to be low.
2 No new influenza virus subtypes have been detected in humans. However, a circulating animal influenza virus subtype poses a substantial risk of human disease.
Pandemic alert phase
3 Human infection(s) with a new subtype but no human-to-human spread, or at most rare instances of spread to a close contact.
4 Small cluster(s) with limited human-to-human transmission but spread is highly localized, suggesting that the virus is not well adapted to humans.
5 Larger cluster(s) but human-to-human spread still localized, suggesting that the virus is becoming increasingly better adapted to humans but may not yet be fully transmissible (substantial pandemic risk).
Pandemic period
6 Pandemic: increased and sustained transmission in general population.

Source: Adapted from U.S. Centers for Disease Control and Prevention, Stages of a Pandemic, at


Temporary Recommendations for a Public Health Emergency of International Concern

Under the IHR 2005, if the WHO Director-General declares a public health emergency of international concern, then the Director-General must issue temporary recommendations (Article 15(1)). The nature of the temporary recommendations depends on the threat, and the IHR 2005 provides possible recommendatory actions (Article 18). Temporary recommendations are not binding under the IHR 2005.

On April 25, 2009, the WHO Director-General issued the temporary recommendation that "€œall countries should intensify surveillance for unusual outbreaks of influenza-like illness and severe pneumonia."€[24] The Director-General did not recommend trade or travel interventions with respect to countries affected by the outbreak. However, some countries have adopted such measures, including issuing travel notices warning against travel to Mexico (e.g., Hong Kong),[25] screening air passengers arriving from affected countries (e.g., Japan),[26] and banning pork exports from Mexico and affected states in the United States (e.g., Russia).[27]

The IHR 2005 do not preclude States Parties from implementing measures that achieve a greater level of health protection than WHO temporary recommendations, provided that such measures are (1) otherwise consistent with the Regulations, and (2) not more restrictive of international trade and travel, and not more invasive or intrusive to persons, than reasonably available alternatives that would achieve the appropriate level of health protection (Article 43(1)) (see analysis below on trade and travel restrictions).

Reporting Cases of Human Influenza Caused by a New Subtype

The IHR 2005 mandates that any case involving human influenza caused by a new subtype must be notified to WHO (Article 6(1) and Annex 2). Thus, States Parties affected by the new swine flu virus must notify WHO of such cases. As of April 25, 2009, WHO has received information on cases from Mexico and the United States. If the virus is confirmed in cases in other WHO member states, those countries too will be under a legal obligation to report them to WHO.

Such reporting is critical for WHO to analyze the threat, and, as has happened in the past, sometimes countries fail to report information (e.g., China's attempt to cover up SARS in 2003).[28] Although questions have been raised about Mexico's reporting of cases,[29] the WHO Director-General has praised Mexico and the United States for their transparency and cooperation in the outbreak investigation.[30]

Rules on Trade Restrictions

Although the WHO Director-General has not issued temporary recommendation advising restrictions on trade, the Director-General can do so if the scientific evidence, scientific principles, a risk assessment, and advice of the Emergency Committee make such recommendations appropriate (Articles 17-18). Any such measures must be no more "€œrestrictive of international traffic and trade . . . than reasonably available alternatives that would achieve the appropriate level of health protection"€ (Article 17(d)). Given that health officials have found no evidence that pork products transmit swine flu,[31] the Director-General is unlikely to recommend trade restrictions against such products.

The IHR 2005 applies a test similar to those in the World Trade Organization (WTO), such as in the General Agreement on Tariffs and Trade (Article XX(b)) and the Agreement on the Application of Sanitary and Phytosanitary Measures (e.g., Articles 2,2. 2.3 and 5.6). Russia's reported ban on pork exports from Mexico and the United States possibly violates the IHR 2005, and might also violate WTO rules, if Russia were a WTO member. Russia's ban is not based on scientific evidence, scientific principles, or a risk assessment because pork products do not transmit swine flu.

Rules on Travel Restrictions

Although the WHO Director-General has not issued temporary recommendations that impact travel, the outbreak's course and the issuance of travel warnings by countries may raise the necessity to think about such measures. The IHR 2005 permits the Director-General to issue temporary recommendations that affect travel (e.g., travel warnings) or individual travelers (e.g., entry screening or medical examinations) (Articles 17-18), and States Parties may also apply measures that affect travel, even if not recommended by the Director-General (Articles 23 and 43(1)). However, such measures must be no more restrictive of travel, nor more invasive and intrusive to persons, than reasonably available alternatives that would achieve the appropriate level of health protection (e.g., Articles 17(d), Article 23(1), 31(2), and 43(1)).

Rules on Public Health Measures and Human Rights

With human-to-human transmission established, the outbreak has raised the potential need for interventions, such as compulsory isolation, quarantine, and treatment,[32] which infringe on civil and political rights. The IHR 2005 and international human rights law recognize the legitimacy of such interventions, provided that they meet specific conditions and are applied in keeping with certain principles.

The IHR 2005 mandates that States Parties "€œshall treat travelers with respect for their dignity, human rights and fundamental freedoms"€ (Article 32), meaning that any intervention that infringes on civil and political rights must

  • Be prescribed by law;
  • Be applied in a non-discriminatory manner;
  • Relate to a compelling public interest in the form of a significant infectious disease risk; and
  • Be necessary to achieve the protection of the public, meaning that the measure must be:
    • Based on scientific and public health information and principles;
    • Proportional in its impact on individual rights to the infectious disease threat posed; and
    • The least restrictive or intrusive measure possible to achieve protection against infectious disease risk.[33]

Human rights concerns may also arise under the right to health, particularly with respect to non-discriminatory access of infected individuals to health care services (e.g., hospitals) and anti-viral drugs (e.g., Tamiflu). Countries affected by swine flu that recognize the right to health need to ensure that potentially scarce health care services and anti-viral treatments are not allocated in ways that discriminate against the poor and most vulnerable members of society.


The swine flu crisis emerged rapidly, and dramatic developments may arise in the coming days. The outbreak's consequences could be far-reaching. With the global economic crisis stressing health systems in middle- and low-income countries,[34] their ability to deal with a swine flu epidemic is suboptimal. The outbreak could also affect the deadlocked negotiations over sharing avian influenza virus samples because it demonstrates how critical virus sharing with WHO is for global influenza surveillance and response. Already clear is the IHR 2005's importance to international disease threats such as the swine flu, and perhaps this crisis will catalyze needed efforts, even in times of global economic crisis, to strengthen compliance with and implementation of the IHR 2005.

About the Author

David P. Fidler, an ASIL member, is the James Louis Calamaras Professor of Law and Director of the Center on American and Global Security at the Indiana University Maurer School of Law, Bloomington (


[1] See David P. Fidler, Global Outbreak of Avian Influenza A (H5N1) and International Law, ASIL Insights, Jan. 2004, at

[2] World Health Organization [WHO], International Health Regulations 2005, (2nd ed. 2008), at [hereinafter IHR 2005].

[3] WHO, Swine Flu Frequently Asked Questions, Apr. 26, 2009, at

[4] U.S. Centers for Disease Control and Prevention, Swine Influenza A (H5N1) Infection in Two Children - Southern California, Mar.-Apr. 2009, at

[5] WHO, Influenza-Like Illnesses in the United States and Mexico Update 2, Apr. 26, 2009, at

[6] U.S. Centers for Disease Control and Prevention, Human Swine Flu Investigation, Apr. 26, 2009, at

[7] World "€œWell Prepared"€ for Virus, BBC News, Apr. 26, 2009, available at

[8] WHO, Influenza-Like Illnesses in the United States and Mexico, Apr. 24, 2009, at

[9] K. Bradshear and J. Healy, As Nations Try to Contain Flu, N.Y. Cases are Confirmed, N.Y. Times, Apr. 26, 2009, available at

[10] S. Boseley, Mexico Granted $205 Million Swine Flu Loan from World Bank, The Guardian, Apr. 27, 2009, available at

[11] Bradshear and Healy, supra note 9; BBC News, supra note 7.

[12] M. Chan, Director-General of WHO, Opening Statement for a Global Telephone News Conference, Apr. 25, 2009, at

[13] H. Branswell, Swine Flu an "€œEmergency of International Concern,"€ WHO Says, Global & Mail, Apr. 25, 2009, at

[14] U.S. Centers for Disease Control and Prevention, supra note 6.

[15] K. Bradshear and J. Healy, U.S. Declares Public Health Emergency Over Swine Flu, N.Y. Times, Apr. 26, 2009, available at

[16] See, e.g., D. G. McNeil, Jr., Flu Outbreak Raises Set of Questions, N.Y. Times, Apr. 26, 2009, available at

[17] Under Article 21(a) of the WHO Constitution, the World Health Assembly has the authority to adopt regulations "€œdesigned to prevent the international spread of disease"€ Under Article 22 of the WHO Constitution, any such regulations enter into force for all WHO member states that have not opted out of such regulations within a specified period of time. No WHO member states opted out of the IHR 2005.

[18] See G. S. Schatz, International Health Regulations: New Mandate for Scientific Cooperation, ASIL Insights, Aug. 2, 2005, at

[19] For a comprehensive overview of the IHR 2005, see David P. Fidler, From International Sanitary Conventions to Global Health Security: The New International Health Regulations, 4 Chinese J. Int'l L. 458 (2005).

[20] The swine flu outbreak is not the first major test of the IHR 2005 because WHO attempted, without success, to apply the IHR 2005 to Indonesia's refusal to share samples of avian influenza A (H5N1) with WHO. On this controversy and the attempted application of the IHR 2005, see David P. Fidler, Influenza Virus Samples, International Law, and Global Health Diplomacy, 14(1) Emerging Infectious Diseases 88 (2008). However, although the controversy concerning virus sharing continued after the IHR 2005 entered into force, the problem began before the IHR 2005 was legally binding on WHO member states. The swine flu outbreak is, therefore, the first test of the IHR 2005 from a disease threat emerging after the IHR 2005 entered into force.

[21] WHO, Statement by the WHO Director-General on Swine Influenza, Apr. 25, 2009, at
[hereinafter WHO Statement].

[22] The WHO Director-General selects the members of the Emergency Committee from the IHR Roster of Experts created under Article 47 of the IHR 2005.

[23] WHO Statement, supra note 21. This decision drew criticism from some experts. See Branswell, supra note 13 (quoting leading public health expert Michael Osterholm as arguing that the decision not to move to Phase 4 "€œsurely flies in the face of all the science that we have"€).

[24] WHO Statement, supra note 21.

[25] K. Bradhsear, Hong Kong, Minding SARS, Announces Tough Measures in Response to Swine Flu, N.Y. Times, Apr. 26, 2009, available at

[26] Hot Arrivals from Mexico Face Swine Flu Scrutiny, Japan Times, Apr. 26, 2009, available at

[27] BBC News, supra note 7; F. Jordans, Swine Flu Fears Prompt Quarantine Plans, Pork Bans, Associated Press, Apr. 26, 2009, available at

[28] David P. Fidler, SARS and International Law, ASIL Insights, Apr. 2003, at http://www/

[29] See, e.g., M. Stevenson, Mexico Swine Flu Deaths Spur Global Epidemic Fears, Associated Press, Apr. 24, 2009, available at ("€œMexico's government had maintained until late Thursday [April 23, 2009] that there was nothing unusual about the flu cases, although this year's flu season had been worse and longer than past years. The sudden turnaround by public health officials angered many Mexicans"€).

[30] Chan, supra note 12.

[31] U.S. Centers for Disease Control and Prevention, Key Facts About Swine Influenza (Swine Flu), at

[32] Jordans, supra note 27 (€œGovernments including China, Russia and Taiwan began planning to put anyone with symptoms of the deadly virus under quarantine€).

[33] These disciplines represent the application of the Siracusa Principles on the Limitation and Derogation of Provisions in the International Covenant on Civil and Political Rights, U.N. Doc. E/CN.4/1984/4 (Sep. 28, 1984), to the context of infectious disease control.

[34] See World Bank, Averting a Human Crisis During the Global Downturn - Policy Options from the World Bank's Human Development Network, Apr. 24, 2009, at