By Brian Hooker, Ph.D, P.E.

Study that found vaccines that don’t prevent viral transmission may accelerate evolution of more virulent strains could mean leading vaccine candidates may make COVID crisis worse.

When a virus infects a population of humans, only those viruses that have a living human host will survive. If a virus is so pathogenic that it kills the human it infected, it dies too.

Therefore, mortality of the host kills the most severe forms of any virus over time. Infection rates may go up, but mortality goes down.

In a 2015 study published in PLOS Biology, researchers hypothesized that vaccination can subvert this process by…