Background: Previous studies suggest that zinc salts may be effective in treating the common cold. Since rhinovirus infections occur primarily in the nasal cavity, an attempt to arrest the infection at the portal of entry seems logical.
Aim: To assess the ability of zinc nasal gel to shorten the duration and reduce the severity of the common cold in healthy adults.
Study design: Randomized, double blind, placebo-controlled study.
Methods: Of 1087 patients screened by telephone, 80 patients were enrolled, all presenting within 24-48 h of the onset of illness. They received one dose per nostril of a nasal gel spray containing either 33 mmol/l zincum gluconicum, or an identical placebo four times daily until their symptoms resolved, for a maximum of 10 days.
Results: Median duration of cold symptoms in the zinc group was significantly shorter than in the placebo group (median [IQR] 4.3 days [2.5-5.5] vs. 6 days [5-8.5], p=0.002). Nasal drainage, nasal congestion, hoarseness, and sore throat were the symptoms most affected. Significant reduction of total symptom scores started from the second day of the study. Adverse effects (mainly nasal stinging) were similar in both groups.
Discussion: Zincum gluconicum nasal gel shortens duration and reduces symptom severity of the common cold in healthy adults, when started within 24-48 h of the onset of illness.