Let’s start by reviewing an important distinction that is relevant to viral infections. As discussed in How is Swine Flu Spread, infection occurs when the virus goes into the body and gets past your immune system. So there are two stages: 1. A person is exposed to the virus, and 2. The virus evades the immune response and gets inside the cell where it starts to reproduce itself.

Most doctors and public health authorities worry about the first one of those. We have much more scientific information about germs than we do about how to enhance host immune responses. That’s because it has been easier and more fashionable to study germs than to study immune resistance to germs. So a lot of energy goes into the discussion of reducing exposure to the virus.

While it is very important to reduce viral exposure, science also supports the importance of enhancing host resistance to disease. The fact is that someone with a well-functioning immune system is less susceptible to infection if exposure occurs. Science has demonstrated some of the variables that can diminish or immune function. Factors that are known to impair immune function and can be expected to increase susceptibility to swine flu include:

• Chronic psychological stress
• Poor sleep
• Poor nutrition
• Sedentary lifestyle
• Alcoholism
• Tobacco smoking

Fortunately, there are things that can be done to counter these immune-diminishing factors. For more detailed suggestions about improving your resistance to germs, read boost your immunity.