Nose response may determine whether a cold makes you sick

A lab study found that how nasal cells respond to rhinovirus — especially how quickly they produce interferon — helps determine whether an infection causes symptoms. Rapid interferon activity limited infection to under 1% of cells, while delayed responses were linked to wider infection, inflammation and more mucus.

Researchers published a study in Cell Press Blue that examined how nasal cells react to rhinovirus, the virus most often causing the common cold. The team grew nasal tissue in the lab to observe cellular and molecular changes after exposure. They identified two broad outcomes: a rapid interferon response that limits viral entry and spread, and a delayed or disrupted response that allows the virus to replicate and triggers inflammation. Those differing responses help explain why only about half of rhinovirus exposures produce symptoms. Key findings: - When interferon is produced quickly, fewer than 1% of nasal cells become infected and the virus is largely contained. - Experimental disruption of the interferon response allowed the virus to spread and replicate more widely in the tissue. - A slower or ineffective interferon response was associated with inflammation, extra mucus production, and infections affecting 30% or more of cells. - Prior recent viral infection appears to keep antiviral responses active in some cases, which can make the interferon response faster. - Cooler temperatures around nasal and lung cells and inhaled pollutants or cigarette smoke were reported as factors that can weaken or alter the interferon response and lead to a more inflammatory outcome. Summary: The study indicates that timing and strength of the nasal interferon response influence whether a rhinovirus exposure remains limited or becomes symptomatic, providing a clearer view of why people vary in cold severity. Undetermined at this time.