Why even herd immunity may not prove to be the best bet against Covid-19

Herd immunity, as a general concept, could mean a more dangerous virus for some areas and population subgroups

The question of herd immunity — specifically, whether some cities and regions are acquiring it sooner than expected and thus have higher than expected protection against Covid-19 — has been attracting more attention lately. Even if this hypothesis is true, however, it still leaves the world with some truly significant challenges and mandates a continuing vigorous fight against the pandemic.

The evidence for herd immunity can be seen in Sweden, for example, where the case and death rate have plummeted, even though the Swedes still don’t wear masks or engage in extreme social distancing. In London, the bars, movie theaters and