Exposure to the rhinovirus, the most frequent cause of the common cold, can protect against infection by the virus which causes COVID-19.
Exposure to the rhinovirus, the most frequent cause of the common cold, can protect against infection by the SARS-CoV-2 virus which causes COVID-19, as per a study at the Yale University, published in the Journal of Experimental Medicine. The common respiratory virus was found to jump-start the activity of interferon-stimulated genes, early-response molecules in the immune system which can halt the replication of the SARS-CoV-2 virus within airway tissues infected with the cold.
‘Exposure to the rhinovirus, the most frequent cause of the common cold, can protect against infection by the SARS-CoV-2 virus which causes COVID-19 by jump-starting the activity of interferon-stimulated genes. This highlights the importance of interferon treatment as a possible benefit early in infection, but not when given later.’
Hence triggering these defenses by treating patients with interferons (an immune system protein that is also available as a drug) early in the course of COVID-19 infection may help in preventing or treating the infection. On the contrary, previous studies suggest that high interferon levels at the later stages of COVID-19 correlated with worse disease outcomes via overactive immune responses.
Interferon-therapy for COVID-19
The team thereby studied this defense system early in the course of COVID-19 infection by infecting a lab-grown human airway tissue with SARS-CoV-2.
It and found that for the first three days, viral load in the tissue doubled about every six hours. However, replication of the COVID-19 virus was completely stopped in tissue that had been exposed to rhinovirus. On blocking these antiviral defenses, the SARS-CoV-2 could replicate in airway tissue previously exposed to rhinovirus.
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"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. There are hidden interactions between viruses that we don't quite understand, and these findings are a piece of the puzzle we are just now looking at," says Ellen Foxman, assistant professor of laboratory medicine and immunobiology at the Yale School of Medicine and senior author of the study.
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Source-Medindia