By Kevin Esvelt

In an essay published in Scientific American, Carolyn Neuhaus and I have called for immediate and intensive research into the possibility that exposure to one of the coronaviruses that cause the common cold could decrease the severity of Covid-19, and could be leveraged to expand what’s been called “pre-existing” immunity to the disease by deliberate transmission of common cold coronaviruses.

We wrote in that article: “Today, we know that recent exposure to common cold coronaviruses confers T cell cross-reactivity against components of SARS-CoV-2, and that people with stronger T cell responses tend to experience fewer COVID-19 symptoms. However, we lack direct evidence that recent shCoV exposure can reduce disease severity.”

As our article may raise questions not easily addressed within the ~1000-word limit, we put together a few clarifying answers for those who may be interested.