https://www.scientificamerican.com/article/denser-cities-could-spare-climate-but-also-increase-virus-transmission/

Who pushes elevator buttons with a naked finger anymore or opens an Uber car door with a bare palm? Who doesn’t hold their breath when passing too close to someone on a crowded sidewalk?

These are among the unspoken rules governing daily life in America’s large cities as the COVID-19 virus spreads through dense urban areas, threatening to infect tens of millions of Americans.