Britain is following the US and Europe in making the most of the limited supply of monkeypox vaccine by administering smaller doses of the vaccine, health officials said on Monday.
Three NHS sites are set to start a pilot trial of the so-called fractional dosing approach, which involves using a vial of the vaccine to deliver up to five separate doses, rather than a single one, by injecting a smaller in between. layers of the skin (intradermal injection).
The Nordic Bavarian 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 intradermally or subcutaneously, with two doses given a month apart.
Those who received the intradermal injection received one-fifth of the subcutaneous dose, but produced similar levels of antibodies to 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 stretching out scarce supplies.
Since early May, more than 40,000 confirmed cases of monkeypox, including a handful of deaths, have been reported in more than 80 countries and regions where the virus is not endemic. As of August 15, there were nearly 3,100 confirmed cases in the UK.
The UK has ordered 150,000 doses of the vaccine, a UK Health Safety Agency (UKHSA) spokesman told Reuters in early August.
Some 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 being reserved for those close contacts who are at the highest risk of serious illness, the UKHSA added on Monday.