Flu season is just around the corner. As winter approaches, the cold forces us into the warmth of our homes, where interactions with our fellow humans are magnified by increased close contact.
These conditions are ideal for the spread of the influenza virus, which is mainly spread by sneezes. A tear-inducing, room-resonating sneeze is a viral ejection of massive proportions.
It starts with a tickling feeling in the nose, grows with each vain attempt at repression of the inevitable, and ends with the violent expulsion of as many as 40,000 projectiles traveling up to 200 miles an hour. Each droplet expelled into the room can contain as many as 100 million flu viruses. The virus-laden water bombs are also released in much less dramatic fashion when someone with the flu talks or coughs. After expulsion from the infected body, the larger droplets fall to ground, while the smaller ones can remain airborne for days. Most flu viruses are spread when these droplets directly enter someone's mouth or nose. It is a common misconception that flu infections come from touching doorknobs, handrails, etc. -- infection from droplets that have landed on a surface is fairly rare.
During the summer, we spend more time outdoors, where we are less likely to breathe in virus-laden droplets. Consequently, outbreaks of the flu are generally limited to the winter season. They peak in about three weeks and take another three to dissipate. In the period between 1976 and 2006, annual flu-associated deaths in the United States ranged from a low of 3,000 to a high of 50,000 people. According to the Centers for Disease Control and Prevention, older people, young children, pregnant woman and people with asthma are particularly susceptible to flu viruses and are at greater risk for serious complications. The annual direct medical costs attributable to the flu in the U.S. average $10.4 billion annually, and the projected lost earnings due to illness and loss of life amount to $16.3 billion.