Treatment of Covid-19 Ambulatory Patients with A Medicinal Preparation of Echinacea Purpurea: The Ecco-2 Investigator-Initiated, Randomised, Double Blind, Controlled Trial
Authors: Pérez Albiac José Luis 
Published: February 2025

Background: The COVID-19 pandemic has affected millions throughout the entire world, causing an unprecedented disruption of the daily lives of many more millions. While vaccines have proven to be a powerful prophylactic tool co contain the spread of the disease, treatment options are very limited. Echinacea phytotherapy is known to be efficacious in the treatment of mild respiratory viral infections, therefore we and others hypothesized that it might be helpful in the treatment of ambulatory COVID-19.

Purpose: To evaluate the clinical efficacy and safety of a medicinal preparation of cryo-milled root of Echinacea purpurea added to the standard-of-care (SOC) treatment in ambulatory COVID-19 patients with mild clinical symptoms, with a respiratory profile.

Methods: We designed and conducted a prospective, double-blind, multicentre, randomized, controlled clinical trial involving four hospitals in Spain, from July 2021 to June 2022. Participants were ambulatory adults with COVID-19 infection, assessed by a positive PCR or antigen test, with mild symptoms of a respiratory profile. Patients were given Echinacea Arkopharma, hard caplets containing 250 mg of Echinacea purpurea (L.) Moench, 1.5 g/day (2 caplets every 8 hours, i.e., 6 g/day, 7 days) added to standard care (vide infra). Participants were followed for 28 additional days. The primary outcome of effectiveness (OE) was OE1: number of days with fever (body temperature ≥ 37ºC at any moment of the day). The secondary outcomes were OE2: days with subjective dyspnea, OE3: days with unsaturation (≤ 96%), OE4: days with disease, OE5: percentage of hospitalizations, OE6: length of hospitalization (days), OE7: days of sick leave, OE8: percentage to visits to emergency room, OE9: percentage of admissions to intensive care units, OE10: percentage of deaths, OE11: subjective perception by the recruiting physician of the treatment usefulness to improve the evolution of the disease, OE12: subjective perception by the patient of the treatment usefulness to improve the evolution of the disease. The secondary outcomes of safety (OS) were OS1: incidence of respiratory adverse effects, OS2: incidence of palpitations (> 110x'), OS3: incidence of transaminase elevations (AST level ≥ 3x the normal range limit), OS4: incidence of headaches, OS5: incidence of digestive adverse effects, OS6: incidence of insomnia and nervousness. For all cases, OS1 to OS6, percentage of dropouts for that specific reason.

Results: The target recruitment number, 230, was not achieved. Rather, 99 eligible patients could be recruited (age 35.50 ± 11.9 years; 51.5 % female). They were randomised to SOC + treatment (n=50) and SOC + placebo group (n=49). There were no statistically significant differences between the treatment and placebo groups in the main variables studied, however, it should be noted that an important limitation of the study is the fact that we could not reach our recruitment target by far. Incidence of serious AEs was nil. Mild AE consisting of diarrhea were seen in 2 cases, and 1 effort- induced tachycardization, although there is no statistical evidence supporting that they were caused by the treatment.

Conclusion: Echinacea, added to the SOC treatment for mild COVID-19, was safe and well tolerated but had no major impact on clinical outcomes. Some effectiveness trends suggest that further studies with full recruitment are warranted to definitively assess its efficacy in moderately affected COVID-19 patients.