Does Vitamin D prevent H1N1

Living in sunny Thailand, I noticed that there is no "winter flu season" like we have in northern countries. How could that be? Are the people of tropical countries getting something that those of us in living in the north lack?

In a paper,  J. J. Cannell explains how vitamin D intake -- obtainable either by way of sunshine or dietary supplement -- explains 14 observations about influenza:

1. Why the flu predictably occurs in the months following the winter solstice, when vitamin D levels are at their lowest,

2. Why it disappears in the months following the summer solstice,

3. Why influenza is more common in the tropics during the rainy season,

4. Why the cold and rainy weather associated with El Nino Southern Oscillation (ENSO), which drives people indoors and lowers vitamin D blood levels, is associated with influenza,

5. Why the incidence of influenza is inversely correlated with outdoor temperatures,

6. Why children exposed to sunlight are less likely to get colds,

7. Why cod liver oil (which contains vitamin D) reduces the incidence of viral respiratory infections,

8. Why Russian scientists found that vitamin D-producing UVB lamps reduced colds and flu in schoolchildren and factory workers,

9. Why Russian scientists found that volunteers, deliberately infected with a weakened flu virus - first in the summer and then again in the winter - show significantly different clinical courses in the different seasons,

10. Why the elderly who live in countries with high vitamin D consumption, like Norway, are less likely to die in the winter,

11. Why children with vitamin D deficiency and rickets suffer from frequent respiratory infections,

12. Why an observant physician (Rehman), who gave high doses of vitamin D to children who were constantly sick from colds and the flu, found the treated children were suddenly free from infection,

13. Why the elderly are so much more likely to die from heart attacks in the winter rather than in the summer,

14. Why African Americans, with their low vitamin D blood levels, are more likely to die from influenza and pneumonia than Whites are.

The whole article is worth reading.   A relatively safe and possibly effective alternative getting a flu shot this winter is to take 4,000 MG of Vitamin D daily.   That's what I'm doing.