common cold

Four seasonal coronaviruses, OC43, 229E, NL63, and HKU1, cause common colds. See how they differ from SARS-CoV-2, why immunity fades, and why most infections stay mild.

Rhinovirus causes most common colds. How it enters nasal cells, why there are over 100 types, why no vaccine exists, and what the evidence says about remedies.