Table of Contents
Influenza Research and Treatment
Volume 2011, Article ID 759051, 8 pages
Clinical Study

Efficacy and Safety of CVT-E002, a Proprietary Extract of Panax quinquefolius in the Prevention of Respiratory Infections in Influenza-Vaccinated Community-Dwelling Adults: A Multicenter, Randomized, Double-Blind, and Placebo-Controlled Trial

1UBC Gerontology and Diabetes Research, 186-828 West 10th Avenue, Vancouver, BC, Canada V5Z 1L8
2Department of Microbiology, Sunnybrook and Women's College Health Sciences Center, Toronto, QN, Canada M4N 3M5
3Clinical Trials Research Center, IWK Health Center, 5850/5980 University Avenue, Halifax, NS, Canada B3K 6R8
4Capital Health, Alberta Health Services, Suite 300, 10216-124 Street, Edmonton, AB, Canada T5N 4A3

Received 5 February 2011; Revised 16 May 2011; Accepted 19 May 2011

Academic Editor: Oleg P. Zhirnov

Copyright © 2011 Janet E. McElhaney et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


CVT-E002 (a proprietary extract) was found to be effective in the prevention of upper respiratory infections (URIs) in healthy adults, and institutionalized and community-dwelling seniors. A multicenter, randomized, double-blind, placebo-controlled trial was carried out to determine effects of CVT-E002 in the prevention of URIs in influenza-vaccinated community-dwelling adults. 783 community-dwelling adults were randomized to receive placebo, 400 mg or 800 mg treatment/d (1 : 1 : 1) for 6 months. Primary analysis on the incidence of laboratory-confirmed-clinical URIs (LCCUs), including influenza A and B, was performed on those receiving at least one dose. Secondary analysis was performed on study completers and included incidence, severity, and duration of URIs meeting a Jackson-based criteria and safety of CVT-E002. The incidence of LCCUs in the ITT group was 5.5%, 5.2%, and 4.6% in the placebo, 400 mg and 800 mg groups, respectively ( ). Jackson-confirmed URIs were significantly lower in the treated groups ( ). CVT-E002 supplementation reduced the severity and duration of Jackson-confirmed URIs. The results indicate that CVT-E002 can be safely used by similar groups and may prevent symptoms of URIs; larger sample size is warranted.