Researchers at Japan’s Jikei University School of Medicine in Tokyo conducted the double blind, fully randomized study during the 2008-2009 winter season. All said, 354 children whom participated in the study were administered 1200 IUs of either vitamin D or placebo for a 3-month period. By the second month of the test, the research team began to notice some initial changes in the experimental group as compared to the control sample.

Conclusion of the study, as published in the American Journal of Clinical Nutrition: “This study suggests that vitamin D3 supplementation during the winter may reduce the incidence of influenza A, especially in specific subgroups of schoolchildren.”

Read the article on Global Healing Center

Debbie Bruck, says in her blog: "You are not protected against swine flu if you received a flu vaccine. NOTE: Many of the deaths that occurred in the great 1918 Flu pandemic can be attributed to the use of aspirin which lowers fever and prevents the body's immune system to fight against the virus by raising the temperature of the body. ... There are a few homeopathic approaches for the onset of flu. As soon as you notice those body aches and pains and you realize this isn't a regular cold, then take a dose of Oscillococcinum ... Influenzinum can be given as pro-active treatment, the same as oscillococcinum. "

Bente Ødegård says in her blog, "An article published in the Journal of the American Institute of Homeopathy in May 1921 (you can download it here) states that Dean W.A.Pearson of Philadelphia collected 26,795 cases of influenza treated by homeopathic physicians with only a mortality rate of 1.05%, while the average conventional medical approach had a mortality rate of 30%. During this time there were many Medical Doctors practicing homeopathic medicine throughout Europe and in America, much to the chagrin of non-homeopathic doctors and pharmacists. While conventional hospitals in the US had an 80-90% loss of life during the scarlet fever, Cholera and Flu epidemics around 1919, Homeopathic Hospitals had only a 2-5% loss."

Another interesting website about Homeopathy for flu is flusolution.net

Dr. Mercola recommends taking vitamine D to avoid flu. Vitamine D it's produced by our own body when it's exposed to sun. But there's also some food with high dose of vitamine D: sardines,  tuna, margarine, cheese, eggs, but the most important source of Vitamine D is Cod's liver oil!