Echinacea Purpurea For the Long-Term Prevention of Viral Respiratory Tract Infections During Covid-19 Pandemic: A Randomized, Open, Controlled, Exploratory Clinical Study

  1. Emil Kolev
  2. Lilyana Mircheva
  3. Michael R. Edwards
  4. Sebastian L. Johnston
  5. Krassimir Kalinov
  6. Rainer Stange
  7. Giuseppe Gancitano
  8. Wim Vanden Berghe
  9. Samo Kreft

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Abstract

SARS-CoV-2 vaccination is effective in preventing severe Covid-19, but efficacy in reducing viral load and transmission wanes over time. In addition, the emergence of novel SARS-CoV-2 variants increases the threat of uncontrolled dissemination and additional antiviral therapies are urgently needed for effective containment. In previous in vitro studies Echinacea purpurea demonstrated strong antiviral activity against enveloped viruses, including SARS-CoV-2. In this study, we examined the potential of Echinacea purpurea in preventing and treating respiratory tract infections (RTIs) and in particular, SARS-CoV-2 infections. 120 healthy volunteers (m,f, 18—75 years) were randomly assigned to Echinacea prevention or control group without any intervention. After a run-in week, participants went through 3 prevention cycles of 2, 2 and 1 month with daily 2,400 mg Echinacea purpurea extract (Echinaforce ® , EF). The prevention cycles were interrupted by breaks of 1 week. Acute respiratory symptoms were treated with 4,000 mg EF for up to 10 days, and their severity assessed via a diary. Naso/oropharyngeal swabs and venous blood samples were routinely collected every month and during acute illnesses for detection and identification of respiratory viruses, including SARS-CoV-2 via RT-qPCR and serology. Summarized over all phases of prevention, 21 and 29 samples tested positive for any virus in the EF and control group, of which 5 and 14 samples tested SARS-CoV-2 positive (RR = 0.37, Chi-square test, p = 0.03). Overall, 10 and 14 symptomatic episodes occurred, of which 5 and 8 were Covid-19 (RR = 0.70, Chi-square test, p > 0.05). EF treatment when applied during acute episodes significantly reduced the overall virus load by at least 2.12 log 10 or approx. 99% ( t -test, p < 0.05), the time to virus clearance by 8.0 days for all viruses (Wilcoxon test, p = 0.02) and by 4.8 days for SARS-CoV-2 ( p > 0.05) in comparison to control. Finally, EF treatment significantly reduced fever days (1 day vs 11 days, Chi-square test, p = 0.003) but not the overall symptom severity. There were fewer Covid-19 related hospitalizations in the EF treatment group ( N = 0 vs N = 2). EF exhibited antiviral effects and reduced the risk of viral RTIs, including SARS-CoV-2. By substantially reducing virus loads in infected subjects, EF offers a supportive addition to existing mandated treatments like vaccinations. Future confirmatory studies are warranted.

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  1. Version published to 10.3389/fphar.2022.856410
  2. ScreenIT

    SciScore for 10.1101/2021.12.10.21267582: (What is this?)

    Please note, not all rigor criteria are appropriate for all manuscripts.

    Table 1: Rigor

    EthicsConsent: Subjects provided written consent prior to their participation and assignment to either the Echinacea or control group.
    IRB: It was approved by the local ethical review board (Ethics Committee at Diagnostics and Consultation Center Convex Ltd, Sofia, registration nr: 116/26.10.2020) and registered on clinicaltrials.gov (identifier: NCT05002179).
    Sex as a biological variablenot detected.
    RandomizationStudy Design and Participants: This randomized, parallel, open, no-treatment controlled, exploratory study was carried out in Bulgaria from 30th of November 2020 (first patient first visit) to 29th of May 2021 (last patient last visit) at one study centre (Diagnostics and Consultation Center Convex EOOD, Sofia).
    Blindingnot detected.
    Power AnalysisSample size calculation & statistics: This study principally used descriptive biometric approaches to estimate effect sizes.

    Table 2: Resources

    No key resources detected.

    Results from OddPub: We did not detect open data. We also did not detect open code. Researchers are encouraged to share open data when possible (see Nature blog).

    Results from LimitationRecognizer: We detected the following sentences addressing limitations in the study:
    As mentioned, this study has limitations, first it used descriptive statistical methods, was small in size and secondly it did not use placebo for control and was not blinded. Nevertheless, the design was still considered valid to provide essential evidence for the preventive use of Echinacea during the COVID-19 pandemic for the following reasons: a first parameter was defined as incidence of (viral) RTIs, for which sample size calculation found sufficient statistical power of >80% for 120 included subjects. The lack of blinding/placebo might be considered a methodological weakness, but it can be assumed that the placebo effect/knowledge of therapy have only limited effects on detection of viral pathogens in NP/OP samples and blood serum. We therefore think that the study design was suitable to address the research question on antiviral effects of Echinaforce in vivo.

    Results from TrialIdentifier: We found the following clinical trial numbers in your paper:

    IdentifierStatusTitle
    NCT05002179CompletedEchinaforce Study to Investigate Explorative Pharmacology an…

    Results from Barzooka: We did not find any issues relating to the usage of bar graphs.

    Results from JetFighter: We did not find any issues relating to colormaps.

    Results from rtransparent:
    • Thank you for including a conflict of interest statement. Authors are encouraged to include this statement when submitting to a journal.
    • Thank you for including a funding statement. Authors are encouraged to include this statement when submitting to a journal.
    • Thank you for including a protocol registration statement.

    Results from scite Reference Check: We found no unreliable references.

    About SciScore

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  3. Version published to 10.1101/2021.12.10.21267582v1 on medRxiv