This is a fascinating interactive visualization of Covid-19 by state over time, created by Dan Goodspeed. The color of the bar indicates whether the state is “blue” or “red” (based on the Cook Partisan Voting Index). The length of each bar shows the number of Covid-19 cases per million people in each state. For example, a value of 10,000 means that 1% of the population of that state has contracted Covid-19 (10,000 divided by 1 million equals 0.01, which is 1%) .
Note how over time the states that have the highest percentage of infection shift from blue states to red states. Initially blue states bore the brunt of the pandemic because of their large urban populations and busy airports with flight connections to sources of Covid-19. Later, these early states took measures to combat the pandemic, but red states did not (even believing Donald Trump’s claims that the pandemic was a hoax and consequently refusing to wear masks or socially distance).
Goodspeed’s website has other visualizations, including for Covid-19 deaths.