WHO Declares Mpox Outbreak a Public Health Emergency of International Concern

Geneva, Switzerland · 23 July 2022 — World Health Organization Director-General Dr Tedros Adhanom Ghebreyesus declared the multi-country outbreak of mpox (then referred to as monkeypox) a Public Health Emergency of International Concern (PHEIC), the highest level of alert under the International Health Regulations (2005). The declaration came despite the IHR Emergency Committee failing to reach consensus, with members split nine against and six in favour.

Dr Tedros acknowledged the deadlock but determined that the outbreak met the criteria for a PHEIC, citing the rapid spread to new countries, the risk of further international transmission, and the need for a coordinated international response to trigger funding and facilitate equitable access to vaccines and treatments.

An Unprecedented Outbreak

Mpox is a viral zoonotic disease caused by the monkeypox virus, an orthopoxvirus. Prior to 2022, the disease had been largely confined to Central and West Africa, where it has been reported since 1970. The 2022 outbreak was unprecedented in its geographic spread, with transmission occurring in countries that had never previously reported cases.

The WHO Secretariat presented data showing that the highest numbers of cases were reported from the WHO European Region and the Region of the Americas. The majority of reported cases occurred among males who identified as gay, bisexual, and other men who have sex with men (MSM), in urban areas, clustered within social and sexual networks.

However, a significant rise in cases was also observed in West and Central African countries, with a different demographic profile — more women and children among cases — and no evidence of sexual transmission presented.

The Committee's Deliberations

The Emergency Committee, chaired by Dr Jean-Marie Okwo-Bele, convened on 21 July 2022. Of the 16 committee members, 15 participated, along with all 10 advisers. The committee was unable to reach consensus on whether the outbreak constituted a PHEIC.

Those in favour argued that the outbreak met all three PHEIC criteria: it was an extraordinary event, it constituted a public health risk through international spread, and it potentially required a coordinated international response. They cited the moral duty to deploy all available tools, the rising case trends, the risk of future waves, and the need to secure equitable access to vaccines and antivirals.

Those against argued that the global risk assessment remained unchanged, that cases were concentrated in a specific population with opportunities for targeted intervention, that disease severity was low, and that a PHEIC declaration could generate stigma and discrimination against affected communities, particularly in countries where homosexuality is criminalised.

Transmission Dynamics and Clinical Presentation

Mathematical models estimated the basic reproduction number (R0) to be above 1 in MSM populations and below 1 in other settings. Country-specific estimates included Spain at 1.8, the United Kingdom at 1.6, and Portugal at 1.4.

The clinical presentation outside Africa was generally a self-limited disease, often atypical compared to previously described outbreaks. Rash lesions were frequently localised to the genital, perineal/perianal, or peri-oral areas, often not spreading further, and appeared prior to the development of lymphadenopathy, fever, and malaise.

The mean incubation period was estimated at 7.6 to 9.2 days, based on surveillance data from the Netherlands, the United Kingdom, and the United States. The mean serial interval was estimated at 9.8 days.

Country Reports

Representatives of Spain, the United Kingdom, the United States, Canada, and Nigeria updated the committee on their epidemiological situations:

Temporary Recommendations

The Director-General issued a comprehensive set of Temporary Recommendations organised into four groups of countries:

• Group 1 (no cases or no detection for 21+ days): Establish coordination mechanisms, surveillance, and readiness.
• Group 2 (recently imported cases or active transmission): Implement coordinated response, community engagement, surveillance, clinical management, and research on medical countermeasures.
• Group 3 (known or suspected zoonotic transmission): Establish One Health coordination between public health, veterinary, and wildlife authorities.
• Group 4 (manufacturing capacity): Increase production and availability of diagnostics, vaccines, and therapeutics at reasonable cost.

All recommendations were to be implemented with full respect for human rights, inclusion, and the dignity of all individuals and communities.

Sources

• WHO statement, Second meeting of the IHR Emergency Committee regarding the multi-country outbreak of monkeypox, 23 July 2022 — who.int
• WHO health topic: Mpox — who.int
• Royal Society of Tropical Medicine and Hygiene — rstmh.org