" There’s a curious correlation between these sunspot peaks and flu epidemics. In the twentieth century, six of the nine sunspot peaks occurred in tandem with massive flu outbreaks. In fact, the worst outbreaks of the century, killing millions in 1918 and 1919, followed a sunspot peak in 1917. This might just be coincidence, of course. Or it might not. Outbreaks and pandemics are thought to be caused by antigenic drift, when a mutation occurs in the DNA of a virus, or antigenic shift, when a virus acquires new genes from a related strain. When the antigenic drift or shift in a virus is significant enough, our bodies don’t recognize it and have no antibodies to fight it—and that spells trouble. It’s like a criminal on the run taking on a whole new identity so his pursuers can’t recognize him. What causes antigenic drift? Mutations, which can be caused by radiation. Which is what the sun spews forth in significantly greater than normal amounts every eleven years. "

― Sharon Moalem , Survival of the Sickest: A Medical Maverick Discovers Why We Need Disease