TL:DR. The spread of COVID-19 is not yet slowing down. The United States hit a ceiling of 100,000 total tests a day a week ago and new positive cases are not reflecting the actual spread of the virus. The percentage of tests that have come back positive has doubled since mid-March indicating testing facilities are prioritizing the obviously sick for testing.
From March 1st until about March 23rd, the rate of reported positive cases in the US increased by about 30%-33% every day then began to slow steadily and is now at around 14% increase in daily reported positive cases.
Why is this not good news? Until that point testing increased daily as well, by around 35% daily, until it slowed, on the 23rd. In fact daily testing has hit a ceiling for now and for the last week the United States has been conducting around 100,000 tests a day.
This in and of itself wouldn’t be troubling. If the spread is in fact slowing down then we would indeed expect the number of tests needed to keep up with new cases to follow suit, but we would also expect to see the percentage of positive tests vs total tests to stay roughly the same or decline overtime. If testing facilities are running out of tests and prioritizing testing people who are definitely sick and obviously symptomatic we would expect to see an increase in the percentage of positive tests vs total tests.
~10% of daily tests were positive mid March. That rate steadily increased and roughly ~20% of daily tests in the US are now positive.
We would also expect to see many more deaths as hospitals become increasingly overburdened. In the US it has been reported that three times as many people have died just in the last week of COVID-19 than have died in all the previous weeks combined.