Is There a Way to Avoid the Flu?

Why is it that many people come down with the flu in winter months but flu is rare in the summer? Why then do new flu strains such as the recent swine flu epidemic affect people even in the summer months? Why is it that the flu shot is often less effect for the elderly? Could it be that there is some factor or factors that allow our immune systems to recognize viruses that are similar but not identical to previously encountered viruses? If this is so, then, if the body had adequate levels of these factors, we would be able to ward off flu infections that were related to previously encountered strains though we would still succumb to new strains such as swine flu. Also, some flu viruses are more closely related to previous viruses than others. If such factors exist, being extremely deficient in these factors could make us susceptible to even closely related flu strains. Flu viruses tend to undergo genetic drift so that the viruses circulating are not genetically identical to the ones that the flu vaccines protect us against so that if we were sufficiently deficient in these factors, the flu shot would not work for us. Many people postulate a link between vitamin D levels and resistance to flu but some research has found problems with this theory. Could it be that while vitamin D is part of the answer there is another missing factor? I believe that factor is calcium. Normally, blood calcium levels are directly affected by vitamin D levels, but if one has hypoparathyroidism and inadequate calcium intake, it is possible to have high vitamin D levels and low calcium levels. Could it be that calcium and vitamin D actually work together to protect against flu and that this is why the research on vitamin D levels is ambiguous? Could it be that having ones vitamin D level and calcium level tested periodically and taking supplements as necessary to insure that both are on the high end of the normal range rather than the low end of the normal range or below normal could protect one against most flu viruses? (Please note that above normal vitamin D levels and above normal calcium levels are both known to cause serious health problems and supplementation that raises either of these levels above normal could be dangerous to ones health. Also, this paper does not constitute medical advice. One should seek the medical advice of a physician before beginning any supplementation of vitamin D or calcium as there are medical conditions for which such supplementation is contraindicated.)