CAN ACUPUNCTURE FIGHT THE FLU ?

According to The World Health Organization, acupuncture is effective in preventing cold and flu as well as shortening the duration of a flu/cold if it is contracted
But why?
Germs are everywhere. Viruses are everywhere. But most of us are not perpetually sick from them. The reason is because our bodies successfully fight the bacteria and viruses in order to keep us well. Problem occur when the body’s systems become too weak to kill the invading ailments
http://roxborough.patch.com/articles/acupuncture-for-flu