On 14 August 2024, the Director-General of the World Health Organization determined that the rise in mpox cases in the Democratic Republic of the Congo and a growing number of African countries constituted a Public Health Emergency of International Concern, the highest alert level under the International Health Regulations.
The decision followed advice from an independent expert committee and reflected two main developments: increasing cases in already affected areas and the spread of a new viral branch, clade Ib, into countries that had not previously reported mpox. Burundi, Kenya, Rwanda and Uganda all reported cases connected to the regional outbreak.
What mpox is and how it spreads
Mpox is a viral disease caused by an orthopoxvirus. It spreads mainly through close contact with an infected person and can cause a painful rash, fever and swollen lymph nodes. In some patients the disease can become severe.
The world had already experienced a large international mpox outbreak beginning in 2022. The 2024 emergency, however, had different geographic and epidemiological characteristics. The outbreak in the Democratic Republic of the Congo and the emergence of clade Ib raised concern that the virus could establish new transmission chains.
Why a PHEIC matters
An international health-emergency declaration does not automatically mean a disease has reached pandemic scale. It is a governance tool designed to focus global attention, coordinate responses and support temporary recommendations to countries.
Its practical value lies in the speed with which it can mobilise surveillance, financing, technical assistance and access to medical countermeasures. In infectious-disease outbreaks, a delay of weeks can substantially change the size of the response required.
The technology behind outbreak control
Modern epidemic management depends on an integrated technology stack. Diagnostic testing separates mpox from other conditions with similar symptoms. Genomic sequencing identifies clades and helps track transmission. Digital surveillance systems aggregate data across different regions.
These capabilities are unevenly distributed. Areas with fewer laboratories and weaker health systems may struggle to detect cases quickly, producing an incomplete epidemiological picture. Official case counts can therefore underestimate real circulation.
Vaccines and distribution
Vaccines originally developed against smallpox can provide protection against mpox, but global availability and the ability to deliver doses to the most affected areas are critical. A technology is not useful simply because it exists; it must reach the right place, be given to priority populations and fit within a coherent epidemiological strategy.
The same is true for tests and therapeutics. Health logistics, which often receive less attention than scientific breakthroughs, can determine whether an outbreak is contained or spreads more widely.
Public information matters too
Infectious-disease emergencies require accurate communication. Public-health authorities need to explain risk behaviours without stigmatising specific communities. Stigma can discourage people from seeking testing or care, making transmission harder to interrupt.
The 2022 outbreak had already shown that targeted messaging, accessible vaccination and community engagement could be important tools. The 2024 emergency again demonstrated the need to combine epidemiology, communication and technology.
A lesson in preparedness
Mpox is also a case study in how the world manages known pathogens that change scale or geography. Not every future emergency will be caused by an entirely new virus. A familiar pathogen can become harder to control when it reaches new populations, changes genetically, shifts transmission patterns or encounters unprepared health systems.
The August 2024 declaration therefore underscored that preparedness is not episodic. Laboratories, sequencing networks, stockpiles, trained staff and international cooperation need to exist before case numbers rise. That invisible infrastructure, more than the emergency declaration itself, determines the strength of the response.
