Early intervention with a glycerol throat spray containing cold-adapted cod trypsin after self-diagnosis of the common cold: a randomised prospective, parallel group and single-blind methods trial (Glycerol-cod trypsin spray in common cold)

Lindberg, F.; Nelson, I.; Ranstam, J.; Riker, D. K.

Background: A glycerol throat spray containing cold-adapted cod trypsin (GCTS) deactivates common cold virus in vitro and decreases pharyngeal rhinovirus load after inoculation in humans. We relied on early self-diagnosis and evaluated two different scales to detect a treatment effect in naturally occurring common colds. Methods: Adults were enrolled in this randomised, prospective, parallel group, single-blind study to begin treatment six times daily at first sign of a common cold or were assigned to a non-treated group. Jackson's symptom scale and the 9-item Wisconsin Upper Respiratory Symptom Survey (WURSS)-21 quality of life (QoL) domain were recorded daily by subjects and area under the curve over 12 days (AUC1-12) calculated. Results: Treatment resulted in reduced symptoms with an AUC1-12 of 45.1 {+/-} 32.5 for Jackson scores compared to 53.8 {+/-} 35.7 in the controls (p=0.023). AUC1-12 for the 9-item WURSS-21 QoL domain was likewise improved, 113.6 {+/-} 107.7 and 152.7 {+/-} 126.3 (p=0.006), respectively. During the first four days fewer of the treated subjects (35.3%) used rescue medication than did the control group (50.4%, p=0.014). Conclusions: Reduction in common cold symptoms was seen with treatment with a glycerol throat spray containing cold-adapted cod trypsin. This effect was best detected with the 9-item WURSS-21 QoL domain.