The % of people who test positive is increasing steadily. It's now up to about 1/3. This could be for any number of reasons for example: you present with serious flu like symptoms, you get tested, you have the flu. This will now be dropping as the flu season comes to an end so a larger % of people with flue like symptoms will actually have COVID. Not because of the rise in covid but because of the fall in Flu.
The only reliable proxy is confirmed covid deaths as this number is related to the number of new cases at some point in the past. However, exactly what point is not known as there is conflicting data about incubation periods and in the future more than now it will also be related to the quality of care that can be given.
There are still plenty of papers being released about this from the same sources as previous stats and they are updating the models as the data set gets bigger.
For anyone who gets concerned when they see large increases is daily case numbers, remember the number of cases reported each day depends on the number of tests done. As the number of tests increases in the coming days the figures may look alarming but you need to take them for what they are.
The reason the US numbers have risen so rapidly in the last few days isn't because suddenly everyone is catching it, it's because suddenly everyone is being tested.