“Herd Immunity” and Response to COVID-19

Regarding the six members of Trump’s campaign team who recently tested positive for COVID-19, a reader remarks, “That’s six steps closer to herd immunity.”

I feel compelled to clarify this.

Herd immunity is protection from infectious disease that occurs when a large percentage of a population has become immune to that infection, whether through vaccination or previous infections, which provides protection for individuals who are not immune.

In the case of COVID-19, we face two challenges.  We have no vaccine, and we aren’t sure what percentage of disease survivors will actually develop immunity.  Scientists estimate that, in the case of the United States, herd immunity will require that ~70% of the population, more that 200 million of our 330 million people, will need to get infected.

If that sounds feasible, let’s examine it for a moment.  Our current number of infections is 2.3 million, so this will require a 8696% increase.  Given that many of our hospital systems are stressed now, one can only imagine what effect would be produced by multiplying the case load by 86.96; needless to say, it would completely collapse our healthcare infrastructure, and drive up the mortality rate by a factor no one can predict.

Some believe that the United States should not have shut down all non-essential parts of its economy and simply dealt with the enormity of the suffering and death (doing this, the U.S. would have been the only country on Earth to take that tack).  Interestingly, scientists tell us that this would have resulted in about 60 million infections, which is 26 times what we’re currently experiencing, but still, less than one-third of the 200 million cases required for herd immunity.