Herd immunity is the resistance to the spread of a contagious disease within a population that results if a sufficiently high proportion of individuals are immune to the disease, especially through vaccination.
The prospects for a vaccine are, according to New Scientist, 21 March 2020, p45, ‘. . . the fastest we have ever cranked out a vaccine in response to an outbreak was with Ebola – and that took five years . . .‘
The other way is to allow 50-80% of the population to become infected quickly so that survivors will be in an immune herd. The strategy has ethical objections that it practices eugenics, aiming to improve the genetic quality of a human population. Some consider it is more ethical and politically viable to suppress the pandemic with economic and social restrictions that wreck the economy.
An article in aljazeera asks: Which countries have allowed the elderly and the sick to die in numbers, as an alternative to widespread economic damage caused by more stringent suppression measures?
Countries have responded differently, as is evident from this table.
|Deaths per million|
It remains to be seen if stringent suppression has merely delayed deaths until later, with more and longer lasting economic damage. A short sharp economic shock from epidemic virulence could possibly be less damaging overall, except for people who are without medical treatment. Countries that adopt a balance between medical and economic constraints may be best placed to countenance the uncertainties.
A possible philosophy is to keep hospital beds treating as many COVID-19 cases as possible.
Data: https://www.worldometers.info/ April 16th, 2020