(NBC NEWS) -- Our society dictates that when meeting someone new, the polite thing to do is shake hands.
But new research suggests the common handshake is great -- if you want to make someone sick.
Infectious disease experts have a better -- and safer -- solution, one endorsed by both President Barack Obama and the Dalai Lama. The "fist bump" may be more hygienic than handshakes.
Infection prevention expert Dr. Mary Lou Manning says our hands are covered with bacteria. While most of it is perfectly safe, there are also potentially dangerous viruses like the flu.
"We're all just little Petri dishes walking around," Manning said. "For most patients, (handshakes) won't be a problem, but for some, it will, and you just never know who those patients might be."
Hands are notorious for passing along germs because we use them to touch everything, including our mouths and eyes. A new study finds the handshake transmits double the amount of bacteria a high five would. The fist bump transmits even fewer.
Still, some experts say a hands-off approach may be safest for patients.