It was only a few years ago in a February that news was coming from the airlines that dangerous contaminants, viruses and bacteria were causing havoc around the world. It is now February again so the Center for Disease Control is looking to prevent the flu by increasing awareness.
Flight crews have colds, the kids that get on board the airline have germs, then you add the close quarters and you have the perfect little petri dish. However, airlines are now becoming more responsible with High Efficiency Particulate Air filters. Also known as HEPA, these filters are used to keep out the smallest of germs and particulates. The system in airplanes works just as a HEPA vacuum would, in that the recirculated air is sucked through aHEPA filter and the clean air is returned.
This type of filtration system on airlines is being used as a first line of defense against viruses and bacteria that can spread quickly across the world. Disease such as the Bird Flu or SARS were most dangerous because of airline travel allowing for it to spread quickly. With further precautions, the risk of a worldwide health pandemic or epidemic can be reduced greatly.