Three NHS sites are to start a pilot trial of the so-called fractional dose approach, which involves using a vial of the vaccine to deliver up to five separate doses – rather than one dose – by injecting a smaller amount into the interlayers of the skin ( intradermal injection). The Bavarian Nordic vaccine – called Jynneos, Imvanex and Imvamune, depending on geography – was designed to be injected into a layer of fat under the skin, known as a subcutaneous injection. The approach is supported by a study of about 500 adults, which compared the performance of the vaccine given either intradermally or subcutaneously, with two doses given about a month apart. Those who received the intradermal injection received one-fifth of the subcutaneous dose, but produced similar levels of antibodies as those who received the original subcutaneous dose, according to a study published in 2015. In recent weeks, both US and EU regulators have backed the fractional-dosing approach to expanding scarce supplies. More than 40,000 confirmed cases of monkeypox — including a handful of deaths — in more than 80 countries and territories where the virus is not endemic have been reported since early May. By August 15, there were almost 3,100 confirmed cases in the UK. The UK has ordered 150,000 doses of the vaccine, a UK Health Agency (UKHSA) spokesman told Reuters earlier in August. About 50,000 doses have already arrived, while the rest are expected in September. Due to limited vaccine stock, the post-exposure vaccination offer is now reserved for those close contacts who are at the highest risk of serious illness, the UKHSA added on Monday.
