I'm curious about that 60% figure. The SF Chronicle article attributes it to the CDC but doesn't include a citation. In web searches on the topic I've found a far lower figure published in such places as the NY Times and Our World In Data. Those sites give a figure of 86 million cases in the US. That's 26% of our 330 million population. I surmise that the 60% figure is an estimate based on the fact that an increasing number of Covid cases go unreported nowadays.