If you want to do everything you can to keep someone else's germs away from you, consider a less formal greeting like a fist bump.

According to a study published in the August issue of the American Journal of Infection Control, tapping knuckles transmits significantly fewer bacteria than either handshaking or high-fiving.

Maybe prominent fist-bumper U.S. President Barack Obama is on to something.

"Adoption of the fist bump as a greeting could substantially reduce the transmission of infectious diseases between individuals," said author David Whitworth of Aberystwyth University in Wales. He and student Sara Mela shook hands, fist bumped and high-fived each other dozens of times in the name of research. They wanted to study greetings because many previous studies have shown how germy ATMs, doorknobs or gas-pump handles can be, but few have looked at handshakes.

One of the people would put on a sterile glove and immerse it in a container full of germs. They would wait for the glove to dry and then greet the other person using one of the three methods. The other person would be wearing a sterile glove. They even tested for duration and intensity of contact. The researchers would then test the sterile glove for bacteria.

Handshaking transferred 10 times more germs than a fist bump. Handshakes also allowed twice as many bacteria to transfer as compared to high-fives and far fewer bacteria were transferred during a fist bump than a high-five. As you may guess, the longer the two hands were in contact and the stronger the grips, the more bacteria were transferred.

"It is unlikely that a no-contact greeting could supplant the handshake; however, for the sake of improving public health we encourage further adoption for the fist bump as a simple, free and more hygienic alternative to the handshake," said Whitworth.

In May, doctors at the University of California Los Angeles School of Medicine published an essay in the Journal of the American Medical Association website likening the health benefits of banning handshakes in health-care settings to banning smoking in public spaces.

However, the doctors are aware of the difficulties in changing custom.

"In an attempt to avoid contracting or spreading infection, many individuals have made their own efforts to avoid shaking hands in various settings but, in doing so, may face social, political, and even financial risks," they wrote.

According to Punchbowl, the handshake may date back to the 2nd century B.C. as a gesture of peace because people were showing that they weren't holding a weapon. Today it is an expression of goodwill, gratitude and congratulations. Trying to ban the handshake may be a nearly impossible task, but it has been done before in Canada.

The Catholic Archdiocese of Winnipeg banned handshaking between churchgoers in 2009 over concerns of spreading swine flu. Emile Loranger, the mayor of L'Ancienne-Lorette, which is just outside of Quebec City, also instituted a ban the same year over the same concerns.

Or Canadians could go even further, like Canadian comedian Howie Mandel, who prefers to tap elbows.

With files from The Associated Press