Choose Your COVID-19 Variable

It has been 183 days of gathering COVID-19 statistics and Day 165 of my shelter in place caution.  On March 1, 2020 I began using World Health Organization data to track cases and deaths in the USA (62 cases and 0 deaths).  I switched to Worldometer Coronavirus on March 24th and started tracking local statistics in April.

Like a good statistician and forecaster, I kept track of my predictions of when hospital beds and/or ICU beds would hit capacity based on some swags about 15% of Cases Hospitalized, 5% ICU and an average of 7 days in hospital using the current daily compounded growth rates.

In the highest daily growth phase (30-35%) early March it was easy to predict without major reduction in growth rates the USA would run out of beds in early April. On April 2 the compound growth rate had dropped in half to 15% and was rapidly decreasing each day (from 15% to 2.3%) so that by May 13 a reasonable 1.5% daily growth rate seem stabilized.   Yet even with that growth rate I was predicting capacity of ICU bed availability by June 16. 

Where was my error?  It was the SWAG of 15% Hospitalization and 5% ICU along with average 7 days in either condition. 

Now with more data the hospitalization numbers are more revealing.   NY Times reported yesterday that USA hospitalization is hovering near the peak of 59,940 on April 15 (on that day the USA had 644,089 Positive Cases; 28,529 Cumulative Deaths; 48,701Recovered; 566,859 Active Cases; and a daily growth rate in positive cases ranging from 4-6%).  That is only 10.6% of the Active Cases.  Consequently my SWAG was double that (20% for both hospitalization and ICU).

Now with more revealing hospitalization numbers the average time in hospital of 7 days was grossly understated and is more likely 22 days depending on age (see Indiana Article - Average COVID-19 Hospital Stay Greater Than Three Weeks).

So  what am I predicting now?    Based on a 1.8% Daily Growth Rate in Positive COVID-19 cases and 10% Hospitalization of Active Cases (which decreases from 49% of Cases by 0.25% daily) - then....  we WILL NOT run out of Hospital Beds.  However ICU may be strained by early October (assuming 2% of the active cases require ICU). 

BTW -  A 1.8% growth rate is still dangerous!  With USA cases at 4.17 Million on 7/23/2020 and a 1.8% Daily growth unchecked the USA will have 66 million positive cases by Christmas.