The Common Cold Helps Protect Against COVID-19

Rhinoviruses have been shown to protect against influenza, can they also help with SARS-COV-2?

A recent study conducted by investigators from Yale University’s School of Medicine has discovered that the rhinovirus, the most common cause of the common cold, can help to protect against the SARS-CoV-2 virus and combat COVID-19.

Results from the study were published in the Journal of Experimental Medicine.

"There appears to be a viral sweet spot at the beginning of COVID-19, during which the virus replicates exponentially before it triggers a strong defense response," Ellen Foxman, senior author on the study and an assistant professor of laboratory medicine and immunobiology at the Yale School of Medicine said. "But it all depends upon the timing."

The team behind the study has done previous work which showed that common cold viruses may protect against influenza, so they set out to study whether they could also help with COVID-19.

For this study, the team infected lab grown tissue from human airways with the SARS-CoV-2 virus and then exposed them to a rhinovirus.

Findings from the study showed that the viral load in the infected tissue doubled roughly every 6 hours, but replication of the virus stopped completely in the tissue that was exposed to the rhinovirus.

Additionally, the investigators studied nasal swab samples from COVID-19 infected patients and saw that there was rapid growth of the virus in the first few days before the immune systems defenses began to kick in, just as they saw in the lab.

“These results, and our findings in longitudinal patient samples, support the concept that airway innate immunity is dynamic, with innate immune defense rapidly changing in response to current and recent viral infections,” the authors wrote. “Our findings also demonstrate that ISG-mediated defenses can profoundly curtail SARS-CoV-2 replication under certain conditions and compel further studies of the role of heterologous innate immunity in protecting against SARS-CoV-2 and other respiratory viruses.