Where's the science behind the CDC's six-foot rule?

They overestimated the role of contaminated surfaces. Some Americans are still wiping down their groceries before bringing them inside. One consequence is that we were slow to recognize the extent of asymptomatic spread. The effort dedicated to scrubbing surfaces wasn’t spent improving air ventilation and filtration, which would have had a greater effect. On the other hand, because of the assumption that Covid spread primarily through droplets and not through smaller aerosols, we underestimated the protective role of wearing high-quality masks.

Experts were trying to protect Americans, and we can’t blame them for being wrong in the absence of good information. The question is whether there is an effective process for establishing these measures and re-evaluating them as new information emerges. Science isn’t a set of unchanging truths handed down by a government agency…

Moreover, the CDC isn’t always clear on when the science is unsettled. This makes it harder for the American public to identify which recommendations are more open to discretion. The agency also doesn’t always identify the underlying science of its recommendations. We don’t know the exact basis for its initial view to stay 6 feet apart.