FluPRINT Study: Characterisation of the Immune and Transcriptional Response to LAIV

In 2013 the UK government introduced the nasal flu spray vaccine (Fluenz Tetra®) for use in children from 24 months to less than 18 years of age. This is a licensed vaccine that is safe, effective and like the injectable vaccine, needs to be given yearly. There is evidence that the nasal spray flu vaccine can offer better protection for children than the injectable flu vaccine but it is not yet fully understood why this is so. When the immune system responds to an infection or a vaccine, specific 'immune response' genes are activated or 'switched on'. This process is called gene expression and different types of immune responses cause the activation of different genes.This study is looking at how specific parts of the immune system like B and T cells respond to the nasal spray vaccine and how and what genes are activated by the vaccine. B cells make antibodies, a part of our immune system that helps to protect against invaders such as viruses or bacteria. The next time our bodies are exposed to the same invader, our B cells make antibodies that can recognise and stop the invader going on to cause an infection. Our T cells can help B cells to make antibodies and also help to direct the body to attack the invader instead of causing harm to healthy cells.