You’ve heard it before: the best defense against the flu and other viruses is to wash your hands frequently and properly. But a new study reveals many of us aren’t washing the right way.

Researchers from Baltimore’s Sinai Hospital found 74 percent of Americans using a public restroom without soap or towels would just rinse their hands with water and let them air dry.

Dr John Cmar, an expert on infectious diseases says that is pointless. "Washing with water alone does not get rid of microbes – the action of working up a lather with soap, and then rinsing it off, is what washes them away. Plus, by touching the sink faucet – one of the dirtiest things in a restroom – these people could be adding even more germs to their hands," he says.

The study also found that people are washing their hands more often because of concern about the H1N1 "swine flu" virus. Nearly 8 out of 10 adults surveyed claim to wash their hands more frequently or thoroughly to avoid getting sick.

In addition to washing your hands, nutritional supplements containing vitamin C, vitamin D, zinc, echinacea and probiotics have also been shown to help boost immunity to avoid the flu and other viruses.