World Health Organization Considers Mpox Emergency Declaration

Update: Mpox is now a Public Health Emergency of International Concern.

Less than two years after the World Health Organization (WHO) first declared a Public Health Emergency of International Concern (PHEIC) over mpox, it’s considering doing so again. To weigh the risks, WHO Director-General Tedros Adhanom Ghebreyesus has convened a committee of experts. Should it vote in favor of declaring a PHEIC, it will only be the eighth such declaration in WHO history.

Such a declaration is not guaranteed. The current outbreak is vastly different from the one that prompted the last declaration. Mpox cases have so far been confined to a few countries in Africa rather than spread across the globe. However, the current outbreak is also proving much deadlier. This is at least in part because the mpox strain driving the surge in cases, Clade I, is a different, more lethal version.

The WHO has declared several PHEICs in the last decade, including the COVID-19, Ebola, and Zika emergencies. Unlike those viruses, however, mpox’s genetic code is encoded in DNA. This trait makes it less prone to developing dangerous mutations. As a result, it has been viewed as a smaller global threat. Even so, it caused a PHEIC in 2022 when cases suddenly appeared in over 100 countries, resulting in over 200 deaths.

In theory, the latest outbreak shouldn’t be difficult to stop. Wealthy nations have built up large stockpiles of effective vaccines, especially after the 2022 outbreak. Additionally, mpox has long been endemic in parts of Africa, killing a handful of people each year but rarely causing large outbreaks—it simply isn’t highly contagious enough.

Confirmed cases of mpox in the DRC have surged in 2024. Source

However, that seems to be changing. First, mpox may have been suppressed by immunity to Smallpox, a similar but far deadlier virus that the world aggressively vaccinated against in the 20th century. Now that Smallpox is gone, that immunity is starting to wane. At the same time, regions where mpox is endemic are rapidly developing, bringing humans in closer contact with animals and one another. Sexual transmission also appears to be playing a bigger role in how mpox spreads. Perhaps due to these factors, the Clade I virus is now capable of sustained human-to-human transmission. Considering how its Clade II cousin caused a global outbreak after achieving this milestone, health officials are alarmed.

Africa's Situation

According to the African CDC, mpox infections increased by 78.5% from 2022 to 2023 and continue to rise this year. The worst-hit country by far is the Democratic Republic of Congo (DRC), which has struggled with surging Clade I cases since 2022. This year, nearly 500 mpox deaths have been reported in Africa, 97% of which occurred in the DRC.

The surge in deaths may be partly due to the emergence of a new Clade I subvariant designated Clade Ib. Cases first appeared at the end of 2023 among sex workers in a border mining town called Kamituga. The virus quickly infected many children via their mothers and spread beyond households. Because many infections have been in Southern Kivu, a region bordering multiple other countries, experts have long warned of cases spreading across Africa.

With many cases of mpox occurring in the border region of South Kivu, the risk of regional spread is high. Source

It appears that those warnings have finally come true: in the last week, Uganda confirmed two mpox cases in travelers from the DRC. Kenya also reported its first case of Clade I. Additionally, suspected cases have occurred in Rwanda and Burundi, which have never had mpox outbreaks but border the DRC. Outbreaks in the Republic of Congo and Central African Republic may also be related to the DRC's, but those links are less clear.

Should the WHO declare a PHEIC, it would hopefully direct international attention to the neglected disease, averting a second global outbreak. Most African countries currently lack access to mpox vaccines used by wealthy nations. Poor healthcare systems and limited diagnostic capabilities further complicate the situation. Much of this can be addressed by international involvement.

Already, the DRC has approved two vaccines, and 50,000 doses have been donated by the US, though they have yet to be delivered. Of course, vaccination alone wasn’t enough to contain the last global outbreak—changes in sexual behavior in gay communities appeared to play a much bigger role. Considering that many cases aren’t resulting from sexual transmission and conditions unique to the DRC, the current outbreak could be Africa’s most difficult to contain.

Global Situation

The last mpox PHEIC was declared when cases were already appearing in dozens of countries, catching authorities off guard. This time, with the WHO already on high alert, outbreaks should be detected more easily. However, there are complications. For example, the Clade Ib virus appears to have mutations that affect the reliability of tests, making it difficult to distinguish it from other mpox strains. Because mpox has been endemic globally rather than just in Africa since 2022, making such a distinction will be critical.

Even so, the risk appears to be lower than in 2022. Since sexual transmission is an important means of spread for the new virus, the same behavioral changes that stopped the last outbreak should still work. Many in high-risk communities such as men who have sex with men (MSM) have been vaccinated for mpox, which further reduces risk. Based on a recent modeling study, highly-vaccinated MSM communities in the United States are likely to experience less than 100 cases should an outbreak of Clade Ib occur. However, more vulnerable communities could still experience thousands of cases, and many such communities exist globally.

A modeling study shows how Clade I mpox could spread in different communities in the United States. Source

Ultimately, the declaration of a PHEIC, if it occurs, will serve as a critical call to action. Whether countries heed that call is another question. In the past, global solidarity has often crumbled in the face of new health threats. Economic interests, political tensions, and a lack of impact in wealthy countries can all undermine efforts.

Yet, there are reasons for optimism. The COVID-19 pandemic, despite its challenges, saw unprecedented scientific collaboration and information sharing. For this to happen with mpox, several key steps must be taken. Wealthy nations should prioritize the distribution of vaccines and medical supplies to the DRC and nearby countries rather than just stockpiling for when mpox reaches their shores. Transparency and information sharing will also be paramount, allowing scientists everywhere to collaborate on the outbreak.

As the world responds to mpox, the actions taken now will not only affect the trajectory of this outbreak but also set a precedent for future global health crises. Mpox should be of concern to all nations—but can they recognize it in time?