Coronavirus

COVID-19 cases have surged in the majority of states in the USA over the last two weeks.   Many governors claim that the surge in cases is mostly due to expanded testing.   A detailed look at the data shows that while some of the increase in case counts is due to expanded testing the majority is not.   The number of tests performed increased throughout April and May in the USA to near 600,000 tests per day, but have not been able to keep up with the surge in newly confirmed cases in June as states reopened too quickly, and individuals failed to follow masking and social distancing guidelines.   The graph below shows that for the largest 3 states, California (CA), Texas (TX), and Florida (FL), the percent of Polymerase Chain Reaction (PCR) tests returning positive results (plotted as 7-day moving averages) have increased in CA to 6%, and surged to historic and alarmingly high levels near 16% in TX and FL.   More importantly, the number of hospital admissions have risen dramatica

COVID-19 case count has been increasing significantly in California in June (see figure below), but compared to some of the other hot states like Florida, Texas, and Arizona, its growth has roughly matched the growth in testing capacity and its positivity rate (percent of test results returning positive) has stayed below 7% unlike FL, TX, and AZ whose positivity rates are more than double this.   While hospitalizations have also increased in CA it has not approached full capacity as they have in TX.   Most importantly its death count has declined through May, and even with the recent outbreaks in June it has remained steady rather than surge along with cases. Death counts usually lag confirmed case counts by 1-2 weeks but we remain optimistic that CA death counts will only increase modestly this summer.   The reasons are fivefold: 1.       Expanded testing has turned up milder and asymptomatic cases which while still contagious do not usually result in deaths. 2.       Expa

New York, New Jersey, and Connecticut have just moved to restrict travel from hot zones around the country.   The states that had the worst Spring outbreak (and whose residents were quarantined by Florida and others) are now requiring Florida and other states’ residents to quarantine for 14 days.   As they might say, “turnabout is fair play” .   A single figure of merit that is not arbitrary or capricious is not easy to agree on, but their definition for current hotness sounds reasonable: more than 10 confirmed COVID-19 cases per 100,000 residents based on a rolling 7-day average.   The table below lists the 8 official ignominious states plus California (CA) which qualified yesterday.   We also include the infection reproduction rate R, and the doubling time for each state as indicators of how fast infections are growing in each state.   The doubling time might also be used as a gating criteria since a state with low current hotness might have a very short doubling time and qualify fo