By Kevin M. Esvelt and Carolyn P. Neuhaus

The ongoing tragedy of the COVID-19 pandemic afflicts every corner of the world. Vaccines may be our best hope for a safe return to workplaces, parties, stores and schools, but even if all leading vaccine candidates are protective, the British charity Oxfam estimates that nearly two thirds of the world’s population will not have access until at least 2022. We suggest a scalable alternative that may prevent morbidity and mortality from Covid-19 in the meantime: the common cold.

Many different studies have shown that infection with one of the seasonal human coronaviruses (shCoVs) responsible for common colds confers a cross-reactive T-cell immune response to SARS-CoV-2, and on September 17, the British Medical Journal published an editorial speculating that “preexisting immunity” to SARS-Cov-2 may result from T cell cross-reactivity.

Might common colds explain a great deal of preexisting immunity, and if so, could the responsible virus help save lives during the current pandemic?