Do More Testing — MAGA!

The US President was recently quoted as saying:

“If we did very little testing, we wouldn’t have the most cases.  So, in a way, by doing all of this testing, we make ourselves look bad” 

You have been poorly advised.  The infections are in the country whether we test or not.  Moreover, now that you have reopened the country, too quickly according to some crazy critics, everyone will get infected sooner rather than later.  The infection rate doesn’t really matter much when everyone is infected.  However, if you can test everyone that is infected you can lower the measured case fatality rate.  A lower fatality rate will make American look great again in the eyes of its own citizens and the world.

The US has a measured fatality rate of 6.0%, better than some countries in Europe but definitely worse than some of the countries lauded as best in class for managing their COVID-19 pandemics better than others: for example South Korea, Taiwan, Australia, and Germany.  Each of these countries has surpassed the US in at least one of two important testing metrics: percent testing positive and tests per capita.    

The most important thing is to test widely and efficiently until a country reaches a low enough positive result rate to feel confident that they have sampled the population well.  When only 1% to 2% of all test results return positive then they can feel confident that they have caught not just the most symptomatic cases but also most of the mildly symptomatic and asymptomatic cases in the population.  This gives countries like South Korea, Taiwan, and Australia confidence that if they can isolate all these patients and all those that they came into close contact with, they will have contained the pandemic.  Equally important it gives their citizens confidence to go out to work and shop — “only a couple percent of the population now test hot and only a couple percent of those will die — not so bad.”  Countries that have tested widely and efficiently all have a lower fatality rate than countries that haven’t (see figure below).  This is partly reflective of the fact that countries that have poor testing capacity can only test the most severely ill and most likely to die.  As they ramp up their testing capacity, they can then test and isolate asymptomatic but infectious cases as well and have a chance to stop the pandemic. 

Until we reach that level, an interim metric that measures how widely a country has tested its population is just the number of tests per capita.  For the US testing 8M people and 2.4% of the population seems like a lot but when 17% of those tests had returned positive, it means that we had only probed the tip of the iceberg.  On this metric the US barely makes it into the top 50 countries around the world, far behind the leader Iceland at 15.1% and behind Germany at 3.3% and Australia at 2.8%.  Germany continues to push testing because their tests returned 6% positive, cumulative to date. 

So, Mr. President, I guarantee you that if you tested more widely you can get positive results down to 1%.  Florida just approached 2.5% a couple of days ago.  When this is achieved on a nationwide cumulative to date basis, the US fatality rate will drop below Germany’s 4.3%. (Theirs will always remain higher than ours because their population is much older than ours, but we will never concede this minor point.) The real point is that you will have beaten your nemesis, Angela Merkel, and all the other big silly EU countries as well as China with their ridiculous 5.6% fatality rate — MAGA!