EU backs changing monkeypox vaccine injection method to boost supply

European countries could stretch out limited supplies of the monkeypox vaccine by administering smaller doses of the shot, the European Medicines Agency (EMA) said on Friday.

The agency’s advice is in line with the so-called fractional dosing approach endorsed by U.S. regulators in which one vial of the vaccine can be used to administer up to five separate doses – instead of a single dose – by injecting a smaller amount in between layers of the skin (intradermal injection).

The vaccine – called Jynneos, Imvanex and Imvamune, depending on geography – was designed to be injected into a layer of fat beneath the skin, known as a subcutaneous injection.

As a temporary measure, national authorities may decide to use the vaccine as an intradermal injection at a lower dose to protect at-risk individuals during the current monkeypox outbreak while supply of the vaccine remains limited, the EMA said.

The recommendation is based on a study involving about 500 adults, which compared the performance of the vaccine given either intradermally or subcutaneously, as two doses given about a month apart.