NEW YORK, April 21 — You’ve probably been cleaning your hands all wrong. They must be filthy.

Scientists have found that a common technique for applying hand sanitizer, one that is even recommended by the Centres for Disease Control and Prevention, is inferior to an alternative method with twice as many steps.

The CDC way:

— Step 1: Apply the sanitizer to one palm.

— Step 2: Rub both palms together.

— Step 3: Rub product over your hands until dry.

In a study published in the journal of the Society for Healthcare Epidemiology of America, scientists in Scotland found that an alternative technique, recommended by the World Health Organisation, was significantly more effective in reducing the median bacteria count on participants’ hands.

It was also more time-consuming. The CDC method takes 35 seconds on average to complete; the alternative, 42.5 seconds.

You may notice that while the three-step instructions include applying the sanitizer and allowing your hands to dry, the six-step technique ignores both actions. (The diagrammed WHO method actually contains 11 intensive steps. The study only counted Steps 2 through 7.)

Here’s how you do it the (much more laborious) WHO way:

— Step 1: Rub palms together.

— Step 2: Rub each palm front to back over the back of the other hand, interlacing fingers.

— Step 3: Twist palms with fingers interlaced, and rub between fingers.

— Step 4: Interlock your fingers, (thumbs should be on opposite sides), and twist again, this time, backs of fingers against palms.

— Step 5: Clasp your left thumb in your right hand and move thumb in circular motion — then switch thumbs.

— Step 6: (Still with us?) Press your right fingers together and rub them in a circular motion on your left palm, then switch. You’re done!

Jacqui Reilly of the Glasgow Caledonian University, the lead author of the study, which focused on health care workers, stressed that the way the steps were counted emphasised the precision of the superior WHO technique.

“The difference between them is that the WHO guidance gives you six manoeuvres to do, instead of just saying, ‘Apply it all over your hands’,” she said.

Hand hygiene, she added, remained “the single most important intervention that you can do to prevent health care-associated infection but also to protect yourself and your family from infections and viruses”.

Certain antibacterial soaps may do more harm than good, experts say. Some have come under scrutiny for using chemicals like triclosan. The Food and Drug Administration has recommended using hand sanitizers that contain at least 60 per cent alcohol if soap and water is unavailable.

Reilly said that while her study focused only on alcohol-based hand sanitizer, the technique applied equally well to hand washing with soap and water.

According to the study, even the health care professionals who participated had trouble with all the steps. Nearly a third of them were unable to complete the entire process despite “having instructions on the technique in front of them and having their technique observed”. — The New York Times