As Coronavirus disease 2019 (Covid-19) spreads across the globe, public health officials and scientists are working hard to warn people of the ways it apparently spreads. First, an infected person coughs or sneezes, passing virus droplets to people and things within a six-foot radius. Next, other people touch surfaces such as doorknobs, desks, and utensils where the virus may have fallen and then touch their faces. Thus, say the experts, we should cover our mouths when we cough or sneeze, frequently and thoroughly wash our hands, and disinfect surfaces.
That is all sound advice. What is not widely discussed, however, is another health hazard that is equally as dangerous: the handshake.
The handshake has a long history as a social ritual. It has been depicted in artwork from as early as the 9th century BCE. In a relief, Assyrian King Shalmaneser III stretches his hand out to a Babylonian ruler, seemingly to seal an alliance. In succeeding centuries, we see many more depictions in art and literature. The handshake was a symbol of peace in Greece, showing that neither individual was wielding a weapon.
In Medieval times, it was thought that knights would shake each other’s hands in order to shake loose any hidden weapons. Walter Burkert, a late professor of classics, aptly wrote: “An agreement can be expressed quickly and clearly in words but is only made effective by a ritual gesture: open, weaponless hands stretched out toward one another, grasping each other in a mutual handshake.”
Strikingly, many cultures have developed different ways of greeting one another. The Maori in New Zealand touch noses. Tibetans stick their tongues out. Male friends in the Democratic Republic of Congo touch foreheads. Ethiopian men touch shoulders. Bowing is the norm in many Asian cultures. Europeans kiss on the cheeks. Still, across much of the world today and especially in the United States, the handshake remains the most common form of greeting.
It’s also seen as a gesture of power and potential domination. We tell our children from an early age to greet others with a firm handshake while also looking them in the eye so as to be seen as confident and strong. This simple behavior happens in boardrooms, when international leaders broker agreements, and on the presidential debate stage.
But what, from a public health perspective, is a handshake? Two hands, both of which may have recently touched mouths, noses, eyes, or surfaces with unknown vectors of illness, coming together. If that sounds dangerous . . . it is!
Research from the University of Colorado has found that the average human hand carries 150 different species of bacteria. And in 2014, a study in the American Journal of Infectious Diseases showed that twice as much bacteria are transferred through a handshake as through a high five. A fist bump transmitted 90 percent less bacteria than a handshake, leading researchers to conclude that adopting such a greeting method would dramatically reduce the times people make each other sick.
Although some people have adopted the fist bump, this alternative greeting is still far from widespread. But now, poised on the brink of a potential outbreak of Covid-19 and still on the tail end of a strong flu season, we should rethink the handshake. Perhaps hospital administrators and the leaders of large gathering areas such as schools, places of worship, and community centers will take a simple stand against hand-shaking, since it holds the potential to dramatically reduce the spread of infectious disease.
As we confront the possibility of a pandemic, we must be prepared for dramatic changes in the way we live and the way we interact. We know from other cultures that there are many ways of greeting each other. We can create handshake-free zones, adopt the fist bump, or even invent new greetings. Long after this virus has come and gone, these simple strategies can help create a healthier future.
Dr. Katherine Gergen Barnett is the vice chair of Primary Care Innovation and Transformation and Residency director in the Department of Family Medicine at Boston Medical Center and Boston University Medical School.