Vitamin D has been used to treat infections before the advent of effective antibiotics. Treatment included exposure to sunlight which was thought to directly kill the infection. Cod liver oil, a rich source of vitamin D has also been employed as a increased protection from infections.
People who have low vitamin D levels may have a higher chance of developing influenza. Influenza epidemics occur in the winter, and vitamin D levels are lower in the winter as well. Since influenza is seasonal, it is thought that vitamin D might be a factor that can affect your chances of getting the flu.
This year 10 times the number of Influenza cases reported compared to the 2013-2014 flu season last year.
Only one in ten children, aged six to 15 years, taking the sunshine vitamin in a clinical trial came down with flu. 50 Percent Reduction In Flu Infections Using Vitamin D
Healthy vitamin D blood levels are between 70 and 90 ng/ml, levels obtained by fewer than 5% of Americans.
The available evidence is of poor quality and provides no guidance regarding the safety, efficacy or effectiveness of influenza vaccines for people aged 65 years or older.
