Professor Fiona Lyons:

It is delivering the vaccine between the layers of the skin. If anyone has ever had a Mantoux test for tuberculosis in the past, they may remember. It is like a little bee sting. As we do not use Mantoux testing any more, the skills for doing intradermal administration are not as widespread within the health service as they were previously, because they are not used that often. The EMA advised that it would give us the opportunity, in the context of limited supply of vaccine, to administer vaccine to more people. We gained the possibility of administering vaccine to more people, as opposed to giving it under the skin. Subcutaneous administration involves a small needle under the skin, usually up in the arm. Intradermally is in the forearm, in the volar aspect of the forearm, in between the layers of the skin.