Previfenon® as Chemoprophylaxis of COVID-19 in Health Workers (HERD)
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ClinicalTrials.gov Identifier: NCT04446065 |
Recruitment Status :
Not yet recruiting
First Posted : June 24, 2020
Last Update Posted : September 9, 2020
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Condition or disease | Intervention/treatment | Phase |
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COVID-19 SARS-CoV2 | Drug: Previfenon® Drug: Placebo | Phase 2 Phase 3 |

Study Type : | Interventional (Clinical Trial) |
Estimated Enrollment : | 524 participants |
Allocation: | Randomized |
Intervention Model: | Parallel Assignment |
Intervention Model Description: | The study will use 2 parallel groups in each center to compare the effects of an oral formulation of EGCG (Previfenon®, patent pending) with those of placebo (starch) in the prevention of respiratory disease caused by SARS-CoV-2 (COVID-19) in health care workers directly exposed to clinical care, daily contact, or traffic of individuals with suspected for COVID-19 during the epidemic outbreak. |
Masking: | Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor) |
Primary Purpose: | Prevention |
Official Title: | A Multicenter, Double-blind, Randomized, Placebo-controlled Clinical Trial to Protect Health Workers Against COVID-19 by Using Previfenon® as Chemoprophylaxis During a SARS-CoV-2 Outbreak. The HERD Study |
Estimated Study Start Date : | September 30, 2020 |
Estimated Primary Completion Date : | September 30, 2021 |
Estimated Study Completion Date : | October 30, 2021 |

Arm | Intervention/treatment |
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Experimental: Previfenon®
Participants will receive coded non-transparent bottles of Previfenon®, each containing 90 EGCG capsules (250 mg per capsule plus excipients) The total EGCG dose per patient will be 750 mg/day (3 capsules) for 40 consecutive days as minimum or a maximum variable time between 60 to 70 days. It will be divided into three daily intakes of one capsule of Previfenon® every 8 hours.
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Drug: Previfenon®
Every capsule of Previfenon® (patent pending) provides 250 mg EGCG ≥ 98% purity with a carefully selected set of excipients to improve flowability, stabilize EGCG against early auto-oxidation, and increase its hepatoprotective activity with prolonged use.
Other Name: Epigallocatechin-3-Gallate, EGCG |
Placebo Comparator: Placebo
Participants will receive coded non-transparent bottles of placebo, each containing 90 starch capsules (250 mg plus excipients) under the same dosage, frequency and duration that Previfenon@ arm.
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Drug: Placebo
Participants will receive placebo starch capsules (250 mg plus excipients) identical in appearance and taste to Previfenon® capsules in a double-blind manner.
Other Name: Starch |
- Event of clinical acute respiratory disease with a diagnosis of COVID-19 confirmed with rtPCR [ Time Frame: The date for censoring a case will be defined as that date when the rtPCR test results positive minus 4 days, with the aim to calculate the time free of clinically defined COVID-19 infection over 40 to 70 days of intervention ]A positive case or event of COVID-19 is defined as a patient with acute respiratory illness presenting fever (37.8º C); at least one of the following symptoms: odynophagia, cough, myalgia, or dyspnea; and a specific positive rtPCR test for SARS-CoV-2.
- Rate of positive cases for IgM and IgG anti-SARS-CoV-2 [ Time Frame: Positive cases in each two-week examination and to the end of the study over 40 to 70 days of intervention ]Rate of positive cases for IgM and IgG anti-SARS-CoV-2 measured by immunochromatographic test in treatment and placebo group at the end of the study
- Composite outcome considering symptomatic and asymptomatic cases with positive rtPCR test [ Time Frame: Positive cases in each two-weeks examination and to the end of the study over 40 to 70 days of intervention ]Rate of asymptomatic cases defined as a positive rtPCR for SARS-CoV-2 viral RNA but with no symptoms of COVID-19 in treatment and placebo group at the end of the study, and a composite outcome considering symptomatic and asymptomatic cases (i.e. all cases with positive rtPCR test)
- Hospitalization due to any acute respiratory infection [ Time Frame: Positive cases in each two-week examination visit and to the end of the study over 40 to 70 days of intervention ]Rate of hospitalizations due to any acute respiratory infection at the end of the study
- Event of upper and lower airway respiratory infection [ Time Frame: Positive cases in each two-week examination and to the end of the study over 40 to 70 days of intervention ]Global frequency of events of upper and lower airway respiratory infections
- Exploratory outcome: Frequency and intensity of selected symptoms for COVID-19 [ Time Frame: Different VAS scores calculated each two-week examination visit over 40 to 70 days of intervention ]Registry of Visual Analogue Scale (VAS) in the log diary of every healthcare worker for the following selected symptoms: cough, muscle pain (myalgia); difficulty breathing (dyspnea); loss of smell (anosmia); loss of taste (ageusia); pain when swallowing (odynophagia, sore throat); and finally headache
- Primary safety outcome: event of major hepatic harm [ Time Frame: Cases accounted by liver profile lab test in each two-week examination visit over 40 to 70 days of intervention. ]Elevation of liver enzymes over 5 times the normal value
- Event of liver enzymes over 3 times the normal value [ Time Frame: Cases accounted by liver profile lab test in each two-week examination visit over 40 to 70 days of intervention ]Elevation of liver enzymes over 5 times the normal value
- Frequency of adverse events [ Time Frame: Records of self-reported adverse effects on log dairy accounted in each examination visit over 40 to 70 days of intervention ]Any adverse event reported over the intervention period

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Ages Eligible for Study: | 25 Years and older (Adult, Older Adult) |
Sexes Eligible for Study: | All |
Accepts Healthy Volunteers: | Yes |
Inclusion Criteria:
- Volunteer healthcare worker with any valid credential of the center
- 25 years old and over
- Not having been diagnosed with COVID-19
- A healthy individual as per investigator's judgment or stating stable non-transmissible chronic disease without hospitalization in the last year, without change of medications or addition of medications to treat chronic illnesses in the last 3 months.
- No pregnancy or breastfeeding
- Female subjects of childbearing potential using an effective family planning method or surgical sterilization or not sexually active during the study
- Do not drink more than 300 ml of tea a day
- Do not take supplements or products containing EGCG during the study
- Being able to set aside time each day to complete the study questionnaires
- Being able to read and understand the informed consent form before the study
Exclusion Criteria:
- Healthcare worker who does not have a valid credential from the center
- Under 25 years of age
- Having been diagnosed with a positive rtPCR for COVID-19
- History of febrile acute respiratory disease within the previous 12 weeks
- Volunteer with significant alteration from laboratory tests (standard biochemical profile and hemogram) at screening. A significant abnormality will be defined according investigator's medical judgment.
- Women during pregnancy or breastfeeding
- Female subjects of childbearing age who are sexually active during the study who do not use an effective method of family planning or do not have surgical sterilization
- Known allergy to green tea or EGCG
- Known starch allergy
- User of any medication or supplement containing EGCG
- Volunteer using immunosuppressive drugs
- Autoimmune disease (Lupus, Sjögren or another), liver disease
- Anemia requiring treatment
- Having a chronic infectious disease under treatment

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT04446065
Contact: Cristian Vargas, MD | +56412467242 | cvargas@melisainstitute.org | |
Contact: Miguel A Bravo, MPH | +56412467242 | mbravo@melisainstitute.org |
Study Director: | Elard S Koch, PhD | MELISA Institute Genomics & Proteomics Research SpA |
Responsible Party: | Elard Koch, PhD, Head of Reserach, MELISA Institute Genomics & Proteomics Research SpA |
ClinicalTrials.gov Identifier: | NCT04446065 |
Other Study ID Numbers: |
MEL109042020 |
First Posted: | June 24, 2020 Key Record Dates |
Last Update Posted: | September 9, 2020 |
Last Verified: | September 2020 |
Individual Participant Data (IPD) Sharing Statement: | |
Plan to Share IPD: | Yes |
Plan Description: | The results of this study will be published as open access article and all IPD that underlie results in a publication will be shared, preferentially as supplementary data set or available in a public repository. Any sensitive personal data/information will be not included. |
Supporting Materials: |
Study Protocol Statistical Analysis Plan (SAP) |
Studies a U.S. FDA-regulated Drug Product: | No |
Studies a U.S. FDA-regulated Device Product: | No |
clinical trial chemoprophylaxis coronavirus antiviral agents epigallocatechin-3-gallate |
COVID-19 Respiratory Tract Infections Infections Pneumonia, Viral Pneumonia Virus Diseases Coronavirus Infections Coronaviridae Infections Nidovirales Infections RNA Virus Infections Lung Diseases |
Respiratory Tract Diseases Epigallocatechin gallate Antioxidants Molecular Mechanisms of Pharmacological Action Protective Agents Physiological Effects of Drugs Antimutagenic Agents Anticarcinogenic Agents Antineoplastic Agents Neuroprotective Agents |