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All Studies   Meta Analysis    Recent:   
0 0.5 1 1.5 2+ Mortality -29% Improvement Relative Risk ICU admission 94% Discharge 78% Quercetin  Onal et al.  LATE TREATMENT  RCT Is late treatment with quercetin + bromelain and vitamin C beneficial for COVID-19? RCT 429 patients in Turkey (May - July 2020) Higher mortality (p=0.57) and lower ICU admission (p=0.39), not sig. Onal et al., Turk. J. Biol.-529, January 2021 Favors quercetin Favors control

Treatment of COVID-19 patients with quercetin: a prospective, single center, randomized, controlled trial

Onal et al., Turk. J. Biol., 45:518-529 (date from preprint), NCT04377789
Jan 2021  
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Quercetin for COVID-19
24th treatment shown to reduce risk in July 2021
*, now known with p = 0.0031 from 11 studies.
No treatment is 100% effective. Protocols combine complementary and synergistic treatments. * >10% efficacy in meta analysis with ≥3 clinical studies.
3,800+ studies for 60+ treatments.
RCT 447 moderate-to-severe hospitalized patients in Turkey, 52 treated with quercetin, bromelain, and vitamin C, showing no statistically significant difference in clinical outcomes. NCT04377789 (history).
This is the 2nd of 10 COVID-19 RCTs for quercetin, which collectively show efficacy with p=0.0049.
This is the 2nd of 11 COVID-19 controlled studies for quercetin, which collectively show efficacy with p=0.0031.
risk of death, 29.3% higher, RR 1.29, p = 0.57, treatment 1 of 49 (2.0%), control 6 of 380 (1.6%).
risk of ICU admission, 94.0% lower, RR 0.06, p = 0.39, treatment 0 of 49 (0.0%), control 14 of 380 (3.7%), NNT 27, relative risk is not 0 because of continuity correction due to zero events (with reciprocal of the contrasting arm).
risk of no hospital discharge, 77.8% lower, RR 0.22, p = 0.10, treatment 1 of 49 (2.0%), control 35 of 380 (9.2%), NNT 14.
Effect extraction follows pre-specified rules prioritizing more serious outcomes. Submit updates
Onal et al., 19 Jan 2021, Randomized Controlled Trial, Turkey, peer-reviewed, 10 authors, study period 7 May, 2020 - 8 July, 2020, this trial uses multiple treatments in the treatment arm (combined with bromelain and vitamin C) - results of individual treatments may vary, trial NCT04377789 (history).
This PaperQuercetinAll
Treatment of COVID-19 patients with quercetin: a prospective, single center, randomized, controlled trial
Hasan Önal, Bengü Arslan, Nurcan Üçüncü Ergun, Şeyma Topuz, Seda Yilmaz Semerci, Mehmet Eren Kurnaz, Yulet Miray Molu, Mehmet Abdussamet Bozkurt, Nurettin Süner, Ali Kocataş
TURKISH JOURNAL OF BIOLOGY, doi:10.3906/biy-2104-16
Introduction Scientific research continues on new preventive and therapeutic strategies against severe acute respiratory syndrome Coronavirus-2 (SARS-CoV-2). So far, there is no proven curative treatment for the novel coronavirus disease 2019 (COVID-19), and while vaccination is continuing worldwide, "wild" protocols based on "ancient" anti-inflammatory and anti-viral drugs are being offered. A valid and alternative therapeutic approach needs to be developed. Affecting the nasopharyngeal cells first, SARS-CoV-2 can target different tissues such as lung, vascular endothelium, kidney and nervous system at various degrees, and it can cause severe illness and death (Russo et al., 2017; Spagnuolo et al., 2018) . With the advantage of the lack of systemic toxicity, flavonoids, including quercetin are proven to potentialize the effects of routine drugs against coronavirus (Ferrer et al., 2008) . Flavonoids owe their antioxidant, anti-inflammatory and anti-viral properties against a wide range of DNA and RNA viruses, to their pleiotropic molecular structure that acts by targeting variable cells on multiple pathways
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Late treatment
is less effective
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