Are We Hurtling or Hurdling Towards Herd Immunity for COVID-19?

Vaccines against COVID-19 were developed in record-smashing time, and now that the rollout has begun, attention is returning to herd immunity, in a real rather than hypothetical sense.

 

Herd immunity refers to the protection against an infectious disease that arises when a critical mass of individuals in a population becomes immune. The pathogen can't find welcoming bodies, and the epidemic dies out. Once herd immunity is attained, mitigation measures can be relaxed. But if society opens too soon, a second and even third wave of disease can ensue – as we've seen.

 

A vaccine, engineered to evoke a strong and diverse antibody response, is more likely to build herd immunity than is natural infection.

 

Establishing herd immunity against COVID-19 requires that a whole bunch of ducks align. The variables include:

 

To continue reading, go to my DNA Science blog, where this post first appeared.