Summary of COVID-19 quercetin studies
1. Gérain et al., NASAFYTOL® supplementation in adults hospitalized with COVID-19 infection: results from an exploratory open-label randomized controlled trial
49 patient quercetin late treatment RCT: 91% lower combined mortality/ICU admission (p=0.02), 89% lower ventilation (p=0.05), 89% lower ICU admission (p=0.05), and 73% higher hospital discharge (p=0.07).RCT 49 hospitalized COVID-19 patients, 25 treated with curcumin and quercetin, shower lower mortality/ICU admission and improved recovery with treatment. All patients received vitamin D. 336mg curcumin, 520mg quercetin, and 18μg vitamin D3 daily for 14 days. The control arm received 20μg vitamin D3 daily. The baseline differences in fever favors the treatment group while the difference in vaccination favors the control group. Figure 1 indicates that 8 patients (2 in Nasafytol, 6 in Fultium) discontinued the supplement or withdrew. However, Section 3 explicitly states, 'All patients included in the FAS population were compliant with the protocol; the PP population was therefore the same as the FAS population.' Unexplained missing data in the day 7 outcome evaluation: Table 2 reports an N=22 for the Nasafytol group for the Day 7 score change. With an original N=25 and 2 withdrawals noted in Figure 1, the evaluated N should be 23. The absence of the 3rd patient is not explained. The..
Jun 2023, Frontiers in Nutrition, https://www.frontiersin.org/articles/10.3389/fnut.2023.1137407/full, https://c19p.org/gerain
2. Rondanelli et al., Promising Effects of 3-Month Period of Quercetin Phytosome® Supplementation in the Prevention of Symptomatic COVID-19 Disease in Healthcare Workers: A Pilot Study
120 patient quercetin prophylaxis RCT: 93% fewer symptomatic cases (p=0.04).RCT 120 healthcare workers, 60 treated with quercetin phytosome, showing lower risk of cases with treatment. Quercetin phytosome 250mg twice a day. Section 2.1 states: 'A maximal follow-up period was determined to be at 3 months.' However, Section 3 (Results) and Figure 4 report data and Kaplan-Meier survival curves extending to 5 months. The authors declare no conflict of interest, however several authors list their affiliation as 'Research and Development Unit, Indena SpA'. Indena SpA is the manufacturer and patent holder of the specific Quercetin Phytosome delivery system tested in this trial. Section 2.1 defines the primary endpoint as 'The termination of the participant's use of the quercetin supplement earlier than 3 months or having an active coronavirus infection' (a prevention endpoint). However, Section 3 states 'The primary endpoint was time to clinical improvement up to day 17 of the infection' (a treatment efficacy endpoint). The text in Section 3 states 'A hazard ratio..
Jan 2022, Life, https://www.mdpi.com/2075-1729/12/1/66/htm, https://c19p.org/rondanelli
3. Tylishchak et al., Effectiveness of the quercetin use in patients with COVID-19 with concomitant type 2 diabetes mellitus
60 patient quercetin late treatment RCT: 15% shorter hospitalization (p<0.0001).RCT 60 hospitalized COVID-19 patients with type 2 diabetes showing quercetin treatment decreased levels of inflammatory markers (interleukin-6, CRP, ferritin), reduced length of hospital stay, and improved capillaroscopy measures compared to standard care. Quercetin was administered at 0.5g intravenously once daily for 10 days. The authors hypothesize the benefits may be due to the anti-inflammatory, antioxidant and endothelium-protective effects of quercetin, Authors explicitly used independent groups Chi-square (Pearson's) and independent groups Student's t-tests to evaluate paired before-and-after data within the exact same groups (e.g., saturation before vs after, χ² for edema before vs after). Table 3 reports values as M±m. The reported t-test values in the text indicate 'm' was treated as the Standard Error of the Mean (SEM). However, the SEM values for the Main Group baseline parameters are very large (e.g., arterial capillary diameter 8.31 ± 1.93). For a sample size of 30, an..
Dec 2024, Wiadomości Lekarskie, https://www.wiadomoscilekarskie.pl/Effectiveness-of-the-quercetin-use-in-patients-with-COVID-19-with-concomitant-type,191875,0,2.html, https://c19p.org/tylishchak
4. Shohan et al., The therapeutic efficacy of quercetin in combination with antiviral drugs in hospitalized COVID-19 patients: A randomized controlled trial
60 patient quercetin late treatment RCT: 86% lower mortality (p=0.24) and 32% faster recovery (p=0.04).Small RCT with 60 severe hospitalized patients in Iran, 30 treated with quercetin, showing shorter time until discharge. All patients received remdesivir or favipiravir, and vitamin C, vitamin D, famotidine, zinc, dexamethasone, and magnesium (depending on serum levels). Quercetin 1000mg daily for 7 days. Table 1 shows the duration of symptoms before randomization was 9.43 days in the Control group and 7.77 days in the quercetin group (P=0.043). Table 1 also shows that fever at baseline was present in 50% of the control group but 80% of the quercetin group (P=0.015). The study was unblinded, and one of the primary endpoints that achieved significance was 'time to discharge'. Hospital discharge is a subjective clinical decision.
Dec 2021, European J. Pharmacology, https://www.sciencedirect.com/science/article/pii/S0014299921007718, https://c19p.org/shohan
5. Di Pierro et al., Possible Therapeutic Effects of Adjuvant Quercetin Supplementation Against Early-Stage COVID-19 Infection: A Prospective, Randomized, Controlled, and Open-Label Study
152 patient quercetin early treatment RCT: 86% lower mortality (p=0.25), 94% lower ICU admission (p=0.006), and 68% lower hospitalization (p=0.003).RCT 152 outpatients in Pakistan, 76 treated with quercetin phytosome, showing lower mortality, ICU admission, and hospitalization with treatment. Potential data issues include: Table 5 hospitalization frequency mismatch: Table 5 reports 7 hospitalized patients for the SC group. The mean length of stay (5.14) matches 36 days across 7 patients. However, the explicit frequency counts below list 15 patients with a total of 90 days. Similarly, Table 5 reports 4 hospitalized patients for the QP group, however the frequency column explicitly lists 3 patients at 1 day and 4 patients at 2 days (summing to 7 patients). This may be a typographical error with several values matching Table 2. Baseline age matching: the age distribution across 7 distinct brackets is very close between the control and treatment groups (maximum difference of 2 patients in any bracket). This level of balance is unusual for a 1:1 simple randomization of 152 patients. Large unadjusted baseline comorbidity imbalance:..
Jun 2021, Int. J. General Medicine, https://www.dovepress.com/possible-therapeutic-effects-of-adjuvant-quercetin-supplementation-aga-peer-reviewed-fulltext-article-IJGM#, https://c19p.org/dipierro
6. Di Pierro et al., Quercetin as a possible complementary agent for early-stage COVID-19: Concluding results of a randomized clinical trial
100 patient quercetin early treatment RCT: 37% improved recovery (p=0.007) and 58% improved viral clearance (p<0.0001).RCT 100 outpatients in Pakistan, 50 treated with quercetin phytosome, showing faster viral clearance and improved recovery with treatment. Patients in the treatment group were significantly younger (41 vs. 54). Authors report performing a covariance analysis but do not provide any data. Table 1 reports the standard deviation for age as exactly 2.03 in both the control group and the quercetin group, which is possible but relatively unlikely. The text states the overall mean age was 47.6 +/- 15.7 years. However, mathematically pooling two groups of n=50 with means of 54.1 and 41.1 and standard deviations of 2.03 yields a combined standard deviation of approximately 6.83, not 15.7. The text states the modal age group was between 30-40 years, comprising 23% of total cases. However, given the reported means and assuming a normal distribution, virtually 0% of the patients would fall into the 30-40 age bracket. It is likely that one or both of the 2.03 standard deviations is a typo..
Jan 2023, Frontiers in Pharmacology, https://www.frontiersin.org/articles/10.3389/fphar.2022.1096853/full, https://c19p.org/dipierro5
50 patient quercetin early treatment RCT: 33% improved recovery (p=0.15) and 50% improved viral clearance (p=0.009).
RCT 50 COVID+ outpatients in Pakistan, 25 treated with curcumin, quercetin, and vitamin D, showing significantly faster viral clearance, significantly improved CRP, and faster resolution of acute symptoms (p=0.154). 168mg curcumin, 260mg quercetin and 360IU cholecalciferol.
Apr 2022, Frontiers in Pharmacology, https://www.frontiersin.org/articles/10.3389/fphar.2022.898062/full, https://c19p.org/khan4q
8. Zupanets et al., Quercetin effectiveness in patients with COVID-19 associated pneumonia
200 patient quercetin late treatment RCT: 29% improved recovery (p=0.5).RCT 200 patients in Ukraine, 99 treated with IV quercetin/polyvinylirolidone followed by oral quercetin/pectin, showing improved recovery with treatment. The paper states 'authors have no conflict of interest to declare.' However, author M. F. Pasichnyk is listed in the affiliations block as the 'General Director of PJSC SIC Borshchahivskiy CPP'. This entity is the Ukrainian pharmaceutical company that manufactures and holds the patents/trademarks for the proprietary intravenous and oral quercetin formulations (Corvitin/Quertin) evaluated in this study. The study was unblinded (open-label). The treatment group received daily intravenous infusions for 10 days, while the control group only received 'basic therapy' without a placebo IV. Because primary measures of efficacy included subjective symptoms like 'general weakness evaluated by VAS' and 'cough,' the lack of blinding and uneven care administration introduces potential bias. The study lacks a CONSORT flow diagram. Mathematical..
Aug 2021, Zaporozhye Med. J., http://zmj.zsmu.edu.ua/article/view/231714, https://c19p.org/zupanets
9. Din Ujjan et al., The possible therapeutic role of curcumin and quercetin in the early-stage of COVID-19—Results from a pragmatic randomized clinical trial
50 patient quercetin early treatment RCT: 29% improved recovery (p=0.11) and 91% improved viral clearance (p=0.05).Small RCT with 50 outpatients, 25 treated with curcumin, quercetin, and vitamin D, showing improved recovery and viral clearance with treatment. 168mg curcumin, 260mg, 360IU vitamin D3 daily for 14 days. Unadjusted baseline differences: the treatment arm had significantly more comorbidities, but the control arm had significantly more myalgia and asthenia, suggesting poor randomization and potential selection bias. In Table 1, the control arm value for '>=5 symptoms' is listed as '15 (60.05)', where 60.05 is a typo for 60.0%.
Jan 2023, Frontiers in Nutrition, https://www.frontiersin.org/articles/10.3389/fnut.2022.1023997/full, https://c19p.org/dinujjanq