Expert says supplies of mpox vaccine unlikely to suffice

Emergent BioSolutions, one of only three companies with a vaccine for mpox, has agreed to donate 50,000 doses of its shot for use in the current outbreak concentrated in central Africa, but an expert has warned supplies are unlikely to meet demand.

The US biotech has pledged the doses of its ACAM2000 vaccine through Direct Relief, a humanitarian organisation, for use in the Democratic Republic of the Congo (DRC) – the epicentre of the outbreak – along with neighbouring countries Burundi, Kenya, Rwanda, and Uganda.

The company said the decision was in response to the WHO's announcement that a surge in mpox cases in central Africa – and first cases in Sweden and the Philippines – constitutes a public health emergency of international concern (PHEIC).

The WHO's decision shortly after the Africa Centers for Disease Control and Prevention (Africa CDC) also declared a public health emergency, after case numbers reached 17,000, including more than 500 deaths.

Emergent's vaccine is under regulatory review for mpox (formerly known as monkeypox) in the US and is already approved by the FDA for smallpox, which is in the same Orthopox virus family.

The company's donation follows a pledge of 40,000 doses from Danish drugmaker Bavarian Nordic, whose Jynneos/Imvanex/Imvamune is approved in the US, Europe, and Canada, while the European Commission will supply another 215,000 doses of the Bavarian Nordic shot from the EU stockpile. However, an infectious disease expert cited by Emergent in its statement said this is a fraction of what is needed.

"Africa CDC estimated they will need 10 million doses to control the epidemic in the continent," said Dr Raina McIntyre, head of the biosecurity programme at the University of New South Wales' Kirby Institute in Sydney, Australia.

"It is unlikely there will be enough supply of third-generation vaccines to control the epidemic in Africa, given demand in other countries," she added.

Following the case of mpox in Sweden, contracted during a stay in an African country where mpox is endemic, there have already been calls for travellers to consider vaccination before visiting the region, raising concerns about the availability of vaccines for Africa.

Emergent and Bavarian Nordic have both said they are ready and willing to scale up production to meet the volume of doses required by the Africa CDC, but the lengthy nature of vaccine manufacturing means that they will need orders to be submitted quickly.

The US company said it has submitted an Expression of Interest to the WHO, proposing that ACAM2000 be added as an agency's Emergency Use Listing (EUL), a risk-based procedure for allowing access to unlicensed medicines in response to health emergencies.

"Currently, we have […] product already in inventory, with the ability to increase supply by approximately 40 million doses, if and potentially when needed," said Emergent's chief executive, Joe Papa.

"The increasing outbreaks of mpox around the world should raise concerns and spur ongoing efforts to produce and stockpile vaccines and treatments to address all Orthopox viruses, including mpox and smallpox," he added.