But a paper published on Tuesday in The BMJ (formerly The British Medical Journal) argues that the six-foot rule is an oversimplification descended from 19th-century science. Instead of single, fixed distancing rules, the authors propose graded guidelines to better reflect the many factors that determine how dangerous a given setting might be.

What does that mean in practical terms? The general scientific consensus, according to Andrew Joseph, Helen Branswell and Elizabeth Cooney of Stat, is that indoors is riskier than outdoors, large groups are riskier than small groups and prolonged contact is riskier than brief contact. Loud talking, heavy breathing, singing and screaming also raise the risk of viral spread.