The US never fixed the core causes of its testing problem. So it’s now seeing the same kinds of issues pop up again. Covid-19 testing in the US improved dramatically over the first half of 2020, but things now appear to be breaking down once more as coronavirus cases rise and outstrip capacity — to the point that the mayor of a major American city can’t get testing quickly enough to potentially avoid spreading the virus. “We FINALLY received our test results taken 8 days before,” Atlanta Mayor Keisha Lance Bottoms tweeted on July 8. “One person in my house was positive then. By the time we tested again, 1 week later, 3 of us had COVID. If we had known sooner, we would have immediately quarantined. Perhaps the National Guard can help with testing too.” Anecdotally, I’ve heard of similar delays across the country — people waiting days or even weeks for their Covid-19 test results after standing in lines for hours to get tested. Labs have warned about problems: Quest Diagnostics, one of the biggest lab companies in the US, said wait times for test results are now averaging between four and six days for most people.“Basically, two things are happening,” Ashish Jha, faculty director of the Harvard Global Health Institute (HGHI), told me. “One is the outbreaks are getting much bigger, so the amount of testing we need to get our arms around the outbreak is going up. And second, what we did [before] was some tweaking on capacity issues to get ourselves up to 500,000 to 600,000 tests a day, but didn’t fundamentally address the supply chain problems.” He added, “This was supposed to be the job of the White House. … But they just never have prioritized really building up a robust testing infrastructure for the country.”