Exploring the origins, and difficulties, of the 6-foot rule
It may have been the most bizarre card game in history.
Groups of men — some sick with the common cold, some healthy — sat around card tables for 12 hours, playing poker. The healthy men wore specially designed arm braces or plastic “collars” that allowed them to handle the cards and chips but made it impossible for them to touch their faces. The sick men were unencumbered and could freely touch the cards, the chips, or their own runny noses. The men were seated about 4.5 feet from one another.
The gonzo poker game was organized by researchers at the University of Wisconsin Medical School for a 1987 study that sought to measure how viral pathogens pass among people via different routes of transmission. Since the healthy men couldn’t touch their faces, the only way they could get sick was by breathing in airborne virus particles expelled by their unwell poker buddies.
Once this first part of experiment was over, the presumably cold virus–infested playing cards and chips that the sick men had handled were immediately transferred to a new lab room, where a fresh batch of healthy volunteers was waiting. These men played poker with the cards and chips for 12 hours and were directed to touch their faces every 15 minutes.
So who got sick? Among the healthy men in the first part of the experiment — the ones who couldn’t touch their faces but were sitting close to ill people — more than half ended up coming down with the common cold. Among the men who had to play with the germ-ridden cards, none got sick. “These results point to aerosol transmission as the most important mechanism of natural spread,” the study authors wrote.
That study is one of several older research efforts that — coupled with more recent work — have helped the Centers for Disease Control and Prevention (CDC) create guidelines designed to stop the spread of viruses and other pathogens. Those guidelines form the foundation of the government’s current SARS-CoV-2 recommendations, including its advice to stay at least six feet away from other people.
Three feet is the “area of defined risk” for health care workers exposed to patients who may carry an infectious disease.
“These studies looked at how likely it was that someone infected would communicate [that infection] to others in a shared environment, and then how far apart people were who became infected,” says Julie Fischer, PhD, an adjunct professor of microbiology and immunology at the Georgetown University Center for Global Health Science and Security. The results of these sorts of experiments are not always perfectly consistent, and most of the data is not specific to SARS-CoV-2. But Fischer says that the CDC’s guidelines are based on the best evidence to date and are designed to afford the public the greatest level of protection.
But guidelines are not laws. And some organizations that are planning to reopen this fall — in…