New cases continue to increase in Hillsborough County as pattern shifts to younger/asymptomatic spread; other states also show concerning rise in case

The prevalence of positive tests is increasing in Hillsborough County. We had some significant increasing in total testing numbers at the beginning of May but not a substantial increase in testing volume recently. Initially, the prevalence dropped but over the last 3 weeks, the prevalence in Hillsborough County has steadily risen from about 2% to about 5%. This mirrors what we are seeing clinically as well.

Interestingly, echoing the recent WHO statements, we are now also seeing more asymptomatic spread. Initially, most of our cases looked different than NYC and areas that high numbers of asymptomatic cases. We know this because we did surveillance testing on thousands of hospital employees (very few had antibody) and also test everyone who is admitted to the hospital (very few of those asymptomatic patients were positive). However, now we are seeing asymptomatic spread as well - more younger patients, many with minimal symptoms.

There was a slope change on standardized day 77 of the outbreak in Hillsborough and Pinellas County (around June 2, 2020) and we are now seeing a significant increase in cases. This slope change corresponds to the trend noted above in which we have seen 12 straight days at or above the mean number of new cases and 7 straight days above 1 standard deviation higher than the mean.

Note that the light blue line (total cases) bends upward steeply around day 80 and the light purple trend line is heading upwards as well.

We have used the nearest-neighbor model in the past to utilize available data to predict where we are heading. Look at the purple George line - the line is heading straight towards Singapore and the slope is now essentially identical. At this point, the Georgia prevalence will be on par with Singapore in a few more days.