London School of Hygiene & Tropical Medicine

The upsurge of mpox in the Democratic Republic of the Congo (DRC) and a growing number of countries in Africa constitutes a public health emergency of international concern (PHEIC), according to an announcement made by the World Health Organization (WHO).

Mpox is an infectious disease with similar but less severe symptoms to smallpox, including fever, swelling of the lymph nodes, pain and skin lesions. It is transmitted through lesion-to-skin contact, including contact during sexual activity and may be transmitted through respiratory droplets.

The new Clade I virus strain, referred to as Clade 1b, has been identified as having novel mutations and is estimated to have emerged around mid-September 2023. The virus has continued to circulate from human-to-human and more than 15,600 cases of infection have been reported since the beginning of 2024, including 537 deaths.

Reacting to the announcement, Michael Marks, Professor of Medicine at the London School of Hygiene & Tropical Medicine (LSHTM), said:

“Declaring a Public Health Emergency of International Concern (PHEIC) is used to highlight the critical importance of a response, to provide a mechanism for strategic co-ordination and to potentially unlock certain forms of funding which are only available in response to an ‘emergency’. 

“It’s clear that this is the largest outbreak of mpox reported from the region. It’s also the largest of the Clade 1 mpox virus, which has traditionally been associated with a higher case fatality rate than Clade 2, which caused the large global outbreak in 2022. 

“It’s generally felt that smallpox vaccination provides some protection against mpox. Smallpox vaccination stopped in DRC around the 1980s, so those who are around 40 years old and over may well have been vaccinated, providing them some protection. Children and younger adults would not have been vaccinated and are therefore at higher risk.

“The best available evidence supports a need for pre-exposure vaccination, where people at risk are vaccinated before they come into contact with a case. There is less strong evidence in support of post-exposure vaccination. 

“We need a large supply of vaccine so that we can vaccinate those most at risk – in the current outbreak that might be sex workers, children and adults living in areas with many cases. If we want a long term solution, we need to consider broader vaccination of the entire population in areas where mpox outbreaks occur to avoid the risk of future outbreaks also getting so large.

“We also need to distinguish between known cases and all cases. We know that not all cases are being detected among adults and children. Children are likely at higher risk of getting sick or having a severe illness and it is therefore not implausible that most cases in children get detected but a larger proportion of cases in adults, where symptoms may be more mild, are missed. We can only find out if reported case numbers are truly representative through better surveillance.

“Traditionally, outbreaks are viewed through the lens of global health security. If it isn’t impacting high income countries, even if an outbreak is very bad, there will likely be insufficient funding. If we looked at it through the perspective of health as a human right, we would already be providing vaccines and interventions to mpox-affected countries, not to prevent emergencies but because people deserve a right to healthcare. 

“It’s clear current mpox control strategies aren’t working and there is an urgent need for more resources including people, money and vaccines.”

Dorien Braam, Assistant Professor in Social Science at LSHTM and member of the UK-Public Health Rapid Support Team (UK-PHRST), said: 

“We don’t currently have enough data at community level to determine exact risks and vulnerabilities for transmission. However, we know that people with existing infections or underlying issues affecting the immune system are more vulnerable. Health inequalities through a lack of access to health services, medication or endemic diseases also make people vulnerable, including children, who constitute a majority of community-transmitted cases in some parts of DRC and Burundi.

“As one of the possible transmission routes is directly from animals to humans, we need to tackle this with a ‘One Health’ approach to monitor potential non-human animal hosts and reservoirs such as rodents and non-human primates. Collaboration across different sectors proved very effective during COVID-19, when veterinary services and laboratories supported surveillance and diagnostics. By engaging and supporting community animal health workers, who are embedded and closely connected in the communities they serve, gaps in surveillance and underreporting can be addressed. 

“To be effective, any interventions and public health messaging must be introduced with community engagement firmly built in. More in-depth social science approaches would also address knowledge gaps through assessing contextual risks and vulnerabilities, and developing a more participatory engagement with communities, who can play an important role in surveillance and as first responders, provided they are supported to do so.  

“Faced with a global shortage of mpox vaccines, international collaboration is also crucial, to address global health inequalities and promote the fair sharing of limited supplies.”

Jimmy Whitworth, Emeritus Professor of Epidemiology at LSHTM, said:

“The current epidemic of Clade 1b mpox in eastern Democratic Republic of Congo and neighbouring countries is very concerning, and it is to be welcomed that Africa Centres for Disease Control (Africa CDC) and the World Health Organization have declared this to be a public health emergency. 

“These declarations amount to a call for action and should lead to the prompt mobilisation of money and resources, and a co-ordinated international response to the epidemic. 

“The epicentre of the epidemic in South Kivu is undergoing a protracted humanitarian crisis and getting the necessary facilities in place for surveillance, diagnostic testing, contact tracing and case management, is going to be very challenging. 

“The amount of vaccine required has been estimated by Africa CDC to be 10 million doses. The cost and availability of vaccine is going to be a great challenge but it is really important that, unlike in the COVID-19 pandemic, there is global solidarity, that the vaccine reaches the people who need it most and that it is not stockpiled by rich countries. 

“This is a real challenge for the global health security community to demonstrate that they can work together for global public good and not for narrow national interests. Let us hope they take that opportunity, otherwise we risk this epidemic spreading across the African continent, and possibly beyond.”