European countries could stretch out their limited stocks of the monkeypox vaccine by changing the way the shot is administered as a temporary measure, the European Medicines Agency (EMA) said on Friday.

The agency’s advice is in line with the approach endorsed by U.S. regulators who have backed using one vial of the vaccine 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 (subcutaneous injection).

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.

More than 40,000 confirmed cases of monkeypox – including a handful of deaths – in over 80 countries where the virus is not endemic have been reported since early May.

The World Health Organization has declared the outbreak a global health emergency. Supplies of the vaccine, made by Bavarian Nordic BAVA.CO, are scarce.

Several countries are stretching out the available doses, with unknown outcomes, to make the most of existing supplies.

Britain, Canada, and Germany are administering one dose per person instead of two, which allows them to inoculate more people even if they each may receive less or less durable protection.