Hate to tell you, but those filters are actually quite useless, the pores are too big.
If you are serious about staying flu free, get medical grade biological filters, they're a bit more expensive, but they work. Although my pulmonologist thinks it's all going to be for nought, as he reckons we're all going to end up getting it anyway.
Just keep an eye out for the symptoms and get to a Doctor ASAP if you get a high fever.
In the meantime, chow down on onions, garlic and ginger, and your immune system should be able to deal with it pretty well. I know a couple of people who have tested positive, and had no more than a cough and mild temperature. The stronger your immune system, the better you'll handle it, and the faster you'll get over it.
