Fun and Informative!
A very well-made movie that also teaches its viewers about how those nasty viruses affect our system! I thoroughly enjoyed this presentation, no doubt you earned high marks at school and here on the Portal in such a short order. Too often, users submit class projects on Newgrounds (often art class) and tend to fall short of their mark - very few have reached the caliber of this film, much less, scientifically-minded movies. For accomplishing that feat, you must be commended, and I recommend that you keep making Flash, as several simple and effective animation techniques were demonstrated in this movie.
The only things that I have to complain about are that the animations in the film were a bit lacking. The effects of blood cells turning in the stream was very well-done, but I think that it could have looked much better (drawing and animating the cell frame-by-frame, for example). Because you kept your explanation sweet and simple, I have no doubt that everyone who saw the film understood it almost entirely as well.
I really think the choice of music helped out your submission, fitting into the scenes very well and giving a sort of mysterious vibe that is akin to the virus' themselves. One more thing that would have made it better is to include a bit more information about the types of virion that affect people and other information about their characteristics (DNA/RNA sequences, how to prevent their spread, etc.).