Rt Covid-19 — How Quickly Coronavirus is Spreading in the American States

This site tracks R_t, the value that measures how many people the average infected person infects, in each of the American states.

An R_t greater than one (depicted as red in this interactive chart) means the virus is spreading to more people. A value less than 1 means it’s on track to die out.

Note that we still don’t know the the extent to which people who’ve had the virus may be vulnerable to re-infection.

We’re all watching the science play out in real time, where targets and interpretations and best practices are shifting. This isn’t like the science you may remember from middle school, where all the answers are already in the teacher’s guide.

Stay home, stay away from each other, wash your hands, and wear your masks whenever social distancing is not possible.

These are up-to-date values for R_t, a key measure of how fast the virus is growing. It’s the average number of people who become infected by an infectious person. If R_t is above 1.0, the virus will spread quickly. When R_t is below 1.0, the virus will stop spreading. —Rt Covid-19