EU backs fractional dosing for monkeypox vaccine

The EU drugs watchdog has backed the implementation of a new monkeypox vaccine strategy that involves administering smaller doses, a move aimed at stretching limited supplies as cases continue to rise globally.

The European Medicines Agency authorised the approach, commonly referred to as fractional dosing, as a temporary measure on Friday. And UK authorities are also giving the approach final consideration, according to people familiar with the matter.

The only available monkeypox vaccine, Bavarian Nordic’s Imvanex, is “only authorised for injection under the skin,” the EMA said. But when given just below the top layer of the skin, a smaller dose of the vaccine can be used.

“Given the currently limited supply of the vaccine, this means that more people can be vaccinated,” it said.

The approach is aimed at helping European health systems to stretch supplies up to fivefold, according to people with knowledge of the matter. One of them said the recommendation was more likely to allow four doses to be extracted.

Fractional dosing has been criticised by Bavarian Nordic, the Denmark-based manufacturer of the vaccine, and some public health experts after the US approved a similar strategy earlier this month. The criticism relates to there being limited data on the efficacy of smaller doses in protecting against monkeypox, although the approach has been used successfully for other vaccines.

The World Health Organization declared the monkeypox outbreak a public health emergency of international concern last month. More than 40,000 cases have been recorded globally since May, according to research group Our World in Data.

The Financial Times reported last week that the UK was close to running out of vaccine supplies and that it was set to not receive any further supplies until late September. The shortage is also severe in Europe, with people crossing borders to get vaccinated because doses are often not available.

Claire Dewsnap, who heads the British Association for Sexual Health and HIV, said it was hoped fractional dosing would be approved in the UK in the next few days.

“I understand it is with ministers now. We’re all really hoping this will be possible,” she said.

There has been discontent inside the UKHSA and among campaign groups about how the agency initially underestimated the number of those eligible for vaccination, according to people with knowledge of the matter.

The UK’s vaccination strategy is “kept under continuous review to ensure doses of the smallpox vaccine are reaching as many people at high risk of exposure as possible”, the UKHSA’s head of immunisation, Mary Ramsay, said in response to questions.

“If there are any changes, they will be announced as and when decisions are taken,” she said, adding that global supplies were limited and that the agency had “acted early to procure the maximum possible number of doses available from the sole global manufacturer”.

Fractional dosing is used for other vaccinations because it enables supplies to be lengthened and has been shown to be as effective as other routes of administration.

Bavarian Nordic said late on Thursday that it had struck a deal to expand production with US company Grand River Aseptic Manufacturing amid surging demand.