You don't have to be a rocket scientist to wash your hands correctly, right?

Wet, lather, rinse. For good measure, sing the "Happy Birthday" song while you're scrubbing to make sure you washed for the full 20 seconds the Centers for Disease Control and Prevention (CDC) recommends. Simple.

But a new study published in the journal Infection Control & Hospital Epidemiology pits the CDC method against the World Health Organization's more detailed technique. Researchers found the WHO's six-step process to be superior at reducing bacteria on hands than the CDC's popular, but relatively skimpy, three-step routine.

After observing doctors and nurses washing up at a teaching hospital, researchers tallied the bacterial count remaining on the health care workers' hands. The WHO's way of washing reduced bacteria from 3.28 to 2.58 (colony forming units per milliliter) while the CDC's hand-washing procedure cut bacteria from 3.08 to 2.88. But the WHO's more complicated method, not surprisingly, took more time to complete: 42.50 seconds versus 35 seconds.

"Hand hygiene is regarded as the most important intervention to reduce health care-associated infections, but there is limited evidence on which technique is most effective,” said lead author Jacqui Reilly, Ph.D., professor of infection prevention and control at Glasgow Caledonian University in Scotland. “This study provides a foundation for effective best practices to implement on the front lines of health care.”

Well, maybe doctors and nurses might need a little Hand Washing 101 if the WHO method is going to be the new standard. Researchers noted study participants didn't always follow all half dozen of the WHO hand-washing steps.

“One of the interesting incidental findings was that compliance with the six-step technique was lacking," said Reilly. "Only 65 percent of providers completed the entire hand hygiene process despite participants having instructions on the technique in front of them and having their technique observed. This warrants further investigation for this particular technique and how compliance rates can be improved."

Although not directly involved with this study, Dr. Philip M. Tierno has been an advocate for serious hand washing for quite some time.

"The CDC merely brings the person to the concept of when to wash your hands and to use alcoholic gel when soap and water is not available. And then stops their advice," says Tierno, professor of microbiology and pathology at NYU School of Medicine and NYU Langone Medical Center. "Whereas [this] carries the ball to completion and is therefore more thorough. And it is not at all excessive. It is simply more complete. Hand washing is the simple most important thing a person can do for their health and is within every body's ability."

The WHO technique is the same one Tierno suggests in his 2000 book, "The Secret Life of Germs."

CDC versus WHO hand washing

bathroom hand-washing sign Just a gentle reminder to lather up and rinse. Hopefully no one needed it. (Photo: Holly Vegter/Shutterstock)

Want to compare the two hand-washing techniques? Here's how the two organizations break them down.

How the CDC says you should wash your hands:

  • Wet your hands with clean, running water (warm or cold), turn off the tap and apply soap.
  • Lather your hands by rubbing them together with the soap. Be sure to lather the backs of your hands, between your fingers and under your nails.
  • Scrub your hands for at least 20 seconds. Need a timer? Hum the "Happy Birthday" song from beginning to end twice.
  • Rinse your hands well under clean, running water.
  • Dry your hands using a clean towel or air dry them.

How the WHO says you should wash your hands:

WHO handwashing technique You better settle in at the sink if you plan on washing your hands the WHO way. (Photo: World Health Organization)

The scoop on drying

bathroom air hand dryer Are bathroom super-fast air dryers as hygienic as they seem? (Photo: Tomwsulcer/Wikimedia Commons)

If you think hand hygiene is all about washing, don't get caught drying your hands on your pants. Hand-washing wars have recently focused on the drying part, too.

There's an assumption that hand dryers are more hygienic than paper towels. But a recent study published in the Journal of Microbiology compared three methods of hand drying: paper towels, warm air dryers and jet air dryers (those super-fast machines that whip the water off your hands in seconds). Researchers found jet air dryers spread 60 times more germs than warm air dryers and 1,300 times more germs than paper towels.

For the study, participants put on gloves then washed their hands in a harmless virus called MS2. They then dried their hands with one of the three methods. The researchers collected samples from surfaces and the air and found jet air dryer blasted the virus farthest — up to 9 feet across the bathroom, compared to the standard dryers, which sent them less than 3 feet, according to the Huffington Post. The paper towels spread the viruses only 10 inches.

Dyson, manufacturer of the jet air dryer, argued that the study didn't reflect a real-world scenario because the participants' hands were covered with many more germs than they would be normally, and paper towels have germs from other users, even if they have fewer airborne germs.

“[The research] has been conducted under artificial conditions, using unrealistically high levels of virus contamination on unwashed, gloved hands,” Dyson said in a statement to The Huffington Post.

Mary Jo DiLonardo Mary Jo writes about everything from health to parenting — and anything that helps explain why her dog does what he does.