The World Health Organization (WHO) has declared mpox (formerly known as monkeypox) to be a public health emergency of international concern, prompting a scramble for vaccines and diagnostics to curb the spread.
In Europe, a single imported case of mpox clade Ib – a severe form of the disease – has been reported in the Stockholm region of Sweden. More cases in Europe are likely, say experts, particularly if outbreaks continue in the Democratic Republic of Congo (DRC).
- By late August 2024, there had been 15,600 mpox cases and more than 500 deaths in DRC
- Mpox is caused by a virus similar to smallpox and cowpox
- It causes blisters on the skin which fill with fluid
- The virus is spread through close personal contact
- Vaccines developed to fight smallpox are effective against mpox
Vaccine production is being scaled up and countries are discussing how to use emergency stockpiles in the short-term. The European Commission says it will procure and donate 175,000 doses of mpox vaccine to be distributed by the African CDC, with the manufacturer donating a further 40,000. It is also working to expand access to diagnostic kids and lab capacity in the region with a €3.5 million expected in early autumn.
However, there are currently no mpox vaccines available in the DRC, according to the New York Times. DRC health minister, Samuel Roger Kamba, said his government first requested vaccines two years ago, but the country is still waiting.
Some observers say the WHO’s system for approving vaccines is slowing down the process. The Organization said it did not have enough data to green light the vaccines, adding that its expert group will meet again in mid-September to consider the latest data. After that, it may be in a position to support their use, which would unblock the flow of vaccines to DRC.
Read more: Is there a monkeypox vaccine?
So, the vaccines may be on the way, but the next question will be how to use them. Professor David Heymann, an infectious diseases expert at London School of Tropical Health & Medicine, says more scientific data is required to inform the vaccination effort. ‘Studies are needed in the DRC where mpox outbreaks are occurring,’ he told Vaccines Today. ‘There are outstanding questions about the epidemiology of the circulating mpox virus, about its natural history and how it affects children and people with HIV, and whether it may be asymptomatic in some individuals – we don’t currently know enough to develop a sound strategy.’
Vaccinating the entire population will not be an option as vaccines will be in short supply and not everyone is a suitable candidate. There are several possible approaches, notably ‘ring vaccination’ – a preventable measure which involves identifying and vaccinating those who may be at direct risk of exposure to an infected individual. Another possibility is to roll out highly targeted vaccination programmes for communities at risk.
Whether one of these approaches – or another strategy entirely – is best suited to the current outbreak is not yet clear. Prof Heymann says the DRC authorities should be leading a coordinated effort to answer these crucial questions.
‘DRC has the scientists and the capability to do this, but needs long-term investment rather than a short-term approach to getting the vaccine into the country,’ he says. ‘None of these [shortcomings] should stop the use of vaccines, but it means we are in a situation where there’s not enough studies to say which vaccination approach is most appropriate.’
Has complacency left the door open to mpox outbreaks?
Prof Heymann and colleagues complained in a Lancet article last year that mpox has been neglected by the global health community for decades. Not only has this left parts of Africa vulnerable to outbreaks, it raises the prospect of a global uptick in cases. And, as the virus is now spreading from person-to-person, the chances of a mutation naturally increases. The big fear is that the mpox virus will fill a ‘niche’ left by the eradication of smallpox unless resources are directed at understanding and stemming current outbreaks.
Understanding of mpox has developed over several decades, but momentum has flagged before a 2022 outbreak captured global attention. That outbreak was driven by clade IIb which is mainly spread through sexual contact. Epidemics were recorded among men who have sex with men (MSM) in multiple countries.
Prof Heymann, who worked on smallpox eradication in the 1970s and spent thirteen years in Africa investigating mpox outbreaks, says evidence of long chains of human transmission – where the virus had been passed from person to person rather than from animal to human – was recorded in the 1990s in DRC. Then in the 2000s, it became clear that those not vaccinated against smallpox (mostly younger people) were at highest risk of mpox.
Scientific interest and public health concern about mpox faded in the intervening years, falling down the long list of priority issues. The availability of a modern vaccine owes more to US defence policy than to coordinated preparedness efforts by global health authorities.
Older generations of smallpox vaccines were not suitable for people with HIV – a community apparently at higher risk of mpox infection. The US Biomedical Advanced Research & Development Authority invested in the development of a vaccine against smallpox (which is also protective against mpox) as a means of countering any threat of bioterrorism involving smallpox. Several industrialised countries are believed to have stockpiles of this vaccine.
Does Europe have enough mpox vaccines?
The European Health Emergency Response Authority (HERA) has negotiated two contracts which enable EU (and European Economy Area) countries access to mpox vaccines. Fourteen countries have signed up the joint contract for Imvanex (a vaccine); thirteen for Tecovirimat (a medicine).
While HERA negotiates and establishes a framework contract, the quantities of vaccine used is a matter for national governments to decide based on their own needs. The current contract for Imvanex runs until November 2024, but deliveries can take place until May 2025. The Tecovirimat arrangement is for the supply of over 100,000 treatment courses of the medicine. It is valid until May 2025.
Both contracts allow for the possibility of donations of the vaccine within and outside the EU to target outbreaks of the disease. The donation agreement signed on 14 August 2024 will see a total of 215,420 mpox vaccines donated to African countries in need.
HERA and the European Civil Protection & Humanitarian Aid Operations (ECHO) are co-managing a stockpile known as rescEU – which contains mpox vaccines and medicines – that can be used as a last resort should a European country be overwhelmed by a major outbreak.
In a statement to Vaccines Today, the European Commission said the experience of expanding vaccine production capacity during the COVID-19 pandemic have helped to prepare for future outbreaks of other infectious diseases, including mpox.
Based on the experience gained during the COVID-19 pandemic, HERA, the [European] Commission services and the Task Force on Industrial scale-up of COVID-19 vaccine production stand ready to respond to any request for assistance and support the scale up the production of vaccines, therapeutics, or any other relevant medical countermeasure needed whenever there is an emergency situation.
WHO experts meet to assess mpox outbreaks
At a meeting earlier this month, a WHO Emergency Committee noted that Clade I mpox had a 10% mortality rate when it was studied by WHO experts in the 1980s, with most deaths occurring in children. This virus is now endemic in DRC. Available data point to a case fatality rate of 3.6%. Clade Ib is a new strain which began spreading in the eastern part of DRC in late 2023.
The WHO Meeting encouraged national immunisation technical advisory groups in affected areas to prepare from the introduction of mpox vaccine, including risk communication and community engagement work to build trust and address stigma.
The meeting concluded that there was currently no cause for implementing travel-related health measures specific for mpox, such as entry or exit screening, or requirements for testing or vaccination.
