Theme 1 - Infection by HIV or the life cycle of HIV
Diagram.1 HIV virus attacking a cell
Theme 2 - Making an antibody
Theme 3 - Fighting an infection
Theme 4 - I got flu !
Diagram 3. The Flu Virus
After the briefing I am drawn to both theme 2 or 3, but I believe that all the themes have the potential to make a great animations with the right style and aimed at targeting the right audience. I think that further research into the subject will help me narrow my choices down.