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Vitamin C COVID-19 studies. The treatment regimen varies widely across studies and may be high-dose IV vitamin C. Recent:
Vitamin C has been officially adopted for early treatment in all or part of 3 countries. Submit updates/corrections.
Sep 20
Early, Late, PrEP, PEP Covid Analysis (Preprint) (meta analysis)
Vitamin C for COVID-19: real-time meta analysis of 52 studies
Details   • Statistically significant improvements are seen for mortality, ICU admission, hospitalization, and recovery. 17 studies from 17 independent teams in 11 different countries show statistically significant improvements in isolation (11 for..
Sep 2
Review Foshati et al., Food Science & Nutrition, doi:10.1002/fsn3.3034 Antioxidants and clinical outcomes of patients with coronavirus disease 2019: A systematic review of observational and interventional studies
Details   Systematic review showing that vitamin C, vitamin D, selenium, and zinc can improve COVID-19 clinical outcomes.
Aug 30
Late Kumar et al., Journal of Family Medicine and Primary Care, doi:10.4103/jfmpc.jfmpc_2437_21
death, ↓23.1%, p=0.60
Efficacy of intravenous vitamin C in management of moderate and severe COVID-19: A double blind randomized placebo controlled trial
Details   RCT 60 ICU patients in India, showing no significant difference in outcomes with vitamin C. Mortality was lower in the vitamin C arm despite having more severe cases at baseline (87% vs. 67%). 1 gram intravenous vitamin C 8 hourly for fou..
Aug 16
PrEPPEP Loucera et al., medRxiv, doi:10.1101/2022.08.14.22278751 (Preprint)
death, ↓28.3%, p=0.002
Real-world evidence with a retrospective cohort of 15,968 Andalusian COVID-19 hospitalized patients suggests 21 new effective treatments and one drug that increases death risk
Details   Retrospective 15,968 COVID-19 hospitalized patients in Spain, showing lower mortality with existing use of several medications including metformin, HCQ, aspirin, vitamin D, vitamin C, and budesonide.
Aug 15
Levels Sinnberg et al., Antioxidants, doi:10.3390/antiox11081580
death, ↓41.9%, p=0.38
Vitamin C Deficiency in Blood Samples of COVID-19 Patients
Details   Analysis of 74 COVID-19 patients and 8 controls in Germany, showing low vitamin C levels associated with mortality. There was no significant difference for vitamin A, D, or E levels. Very few group details are provided, for example the ag..
Aug 8
Meta Bhowmik et al., Health Science Reports, doi:10.1002/hsr2.762 (meta analysis)
death, ↓46.0%, p<0.0001
Impact of high-dose vitamin C on the mortality, severity, and duration of hospital stay in COVID-19 patients: A meta-analysis
Details   Meta analysis of 15 studies with 2,125 COVID-19 patients showing significantly lower mortality with high-dose vitamin C.
Jul 27
Late Fogleman et al., The Journal of the American Board of Family Medicine, doi:10.3122/jabfm.2022.04.210529
no recov., ↓4.4%, p=0.83
A Pilot of a Randomized Control Trial of Melatonin and Vitamin C for Mild-to-Moderate COVID-19
Details   Early terminated low-risk patient RCT with 32 low-dose vitamin C, 32 melatonin, and 34 placebo patients, showing faster resolution of symptoms with melatonin in spline regression analysis, and no significant difference for vitamin C. All ..
Jul 19
Late Izzo et al., Pharmacological Research, doi:10.1016/j.phrs.2022.106360
no recov., ↓41.4%, p<0.0001
Combining L-Arginine with Vitamin C Improves Long-COVID Symptoms: The Nationwide Multicenter LINCOLN Study
Details   Long COVID trial comparing L-arginine + vitamin C with multivitamin treatment (vitamin B1, B2, B6, B12, nicotinamide, folic acid, pantothenic acid), showing significant improvement in symptoms with L-arginine + vitamin C treatment.
Jul 15
Animal Zuo et al., bioRxiv, doi:10.1101/2022.07.14.499651 (Preprint)
animal study
Vitamin C is an efficient natural product for prevention of SARS-CoV-2 infection by targeting ACE2 in both cell and in vivo mouse models
Details   In Vitro and mouse study showing vitamin C inhibits SARS-CoV-2. Vitamin C lowered ACE2 protein levels in a dose-dependent manner at a concentration of 1-10mM in both cell and humanized ACE2 mouse models.
Jun 16
Early Ortore et al., International Journal of Translational Medicine, doi:10.3390/ijtm2020022 Evaluation of the Clinical Effects of an Antiviral, Immunostimulant and Antioxidant Phytotherapy in Patients Suffering from COVID-19 Infection: An Observational Pilot Study
Details   Retrospective case series of 240 patients in Italy in 2020, up to 96 years old, showing no mortality and 1.6% hospitalization with early treatment including vitamin C, quercetin, and green tea and red wine polyphenols. The formulation was..
Jun 7
Early Usanma Koban et al., Bratislava Medical Journal, doi:10.4149/BLL_2022_082
viral+, ↓33.0%, p=0.73
The factors affecting the prolonged PCR positivity in COVID-19 patients
Details   Retrospective 126 patients in Turkey, showing no significant difference in PCR+ at day 14 with vitamin C treatment.
May 30
Early Kumar et al., Cureus, doi:10.7759/cureus.25467
no recov., ↓89.2%, p=0.05
Efficacy and Safety of Aspirin, Promethazine, and Micronutrients for Rapid Clinical Recovery in Mild to Moderate COVID-19 Patients: A Randomized Controlled Clinical Trial
Details   RCT 260 patients in India, 130 treated with aspirin, promethazine, vitamin C, D, B3, zinc, and selenium, showing faster recovery with treatment. There was no hospitalization, ICU admission, or supplemental oxygen requirements in either gr..
May 27
PrEPPEP Galmés et al., Nutrients, doi:10.3390/nu14112254 Suboptimal Consumption of Relevant Immune System Micronutrients Is Associated with a Worse Impact of COVID-19 in Spanish Populations
Details   Ecological study in Spain, showing lower intake of vitamin D, A, B9, and zinc in regions with the highest COVID-19 incidence and mortality. Vitamin D intake was associated with lower prevalence, incidence, and a combined incidence+mortali..
May 19
Late Hellou et al., Journal of Cellular and Molecular Medicine, doi:10.1111/jcmm.17337
NEWS2, ↓76.7%, p=0.04
Effect of ArtemiC in patients with COVID-19: A Phase II prospective study
Details   RCT 50 hospitalized patients in Israel, 33 treated with curcumin, vitamin C, artemisinin, and frankincense oral spray, showing improved recovery with treatment.
May 18
Late Yildirim et al., Research Square, doi:10.21203/ (Preprint) Mortality Predictors Of Pre-variant SARS-CoV-2 Infected ARDS Patients Receiving Favipiravir and Tocilizumab
Details   Retrospective 60 ICU patients in Turkey treated with tocilizumab and favipiravir, reporting that there was a higher rate of vitamin C treatment in surviving patients (35% vs 10%; p = 0.03), however the results in the table do not match. T..
May 13
Late Zangeneh et al., Obesity Medicine, doi:10.1016/j.obmed.2022.100420
death, ↓4.0%, p=0.86
Survival analysis based on body mass index in patients with Covid-19 admitted to the intensive care unit of Amir Al-Momenin Hospital in Arak – 2021
Details   Retrospective 193 ICU patients in Iran, showing no significant difference with vitamin C treatment.
Apr 20
In Silico Pandya et al., Informatics in Medicine Unlocked, doi:10.1016/j.imu.2022.100951
In Silico
Unravelling Vitamin B12 as a potential inhibitor against SARS-CoV-2: A computational approach
Details   In Silico study showing significant interaction with SARS-CoV-2 targets for multiple vitamins.
Mar 29
Late Hess et al., Internal and Emergency Medicine, doi:10.1007/s11739-022-02954-6
death, ↓20.0%, p=0.54
High-dose intravenous vitamin C decreases rates of mechanical ventilation and cardiac arrest in severe COVID-19
Details   Retrospective 100 severe condition hospitalized patients in the USA, 25 treated with high dose IV vitamin C, showing lower mechanical ventilation and cardiac arrest, and increased length of survival with treatment. 3g IV vitamin C every ..
Mar 19
Late Coppock et al., Life, doi:10.3390/life12030453
progression, ↓5.0%, p=0.64
Pharmacologic Ascorbic Acid as Early Therapy for Hospitalized Patients with COVID-19: A Randomized Clinical Trial
Details   RCT with 66 very late stage (8 days from symptom onset) hospitalized patients, 44 treated with vitamin C and 22 control patients, showing no significant differences with treatment.
Mar 11
Late Salehi et al., Research Square, doi:10.21203/ (Preprint)
death, ↓10.1%, p=0.56
Risk factors of death in mechanically ventilated COVID-19 patients: a retrospective multi-center study
Details   Retrospective 125 mechanically ventilated ICU patients in Iran, showing no significant difference with vitamin C treatment in unadjusted results.
Feb 28
PrEPPEP Shehab et al., Tropical Journal of Pharmaceutical Research, doi:10.4314/tjpr.v21i2.13
severe case, ↓4.3%, p=1.00
Immune-boosting effect of natural remedies and supplements on progress of, and recovery from COVID-19 infection
Details   Retrospective survey-based analysis of 349 COVID-19 patients, showing no significant difference with vitamin C prophylaxis in unadjusted analysis. REC/UG/2020/03.
Feb 28
PrEPPEP Nimer et al., Bosnian Journal of Basic Medical Sciences, doi:10.17305/bjbms.2021.7009
hosp., ↓24.7%, p=0.08
The impact of vitamin and mineral supplements usage prior to COVID-19 infection on disease severity and hospitalization
Details   Retrospective survey based analysis of 2,148 COVID-19 recovered patients in Jordan, showing lower risk of severity and hospitalization with vitamin C prophylaxis, without statistical significance.
Feb 26
In Vitro Hajdrik et al., Foods, doi:10.3390/foods11050694 (In Vitro)
In Vitro
In Vitro Determination of Inhibitory Effects of Humic Substances Complexing Zn and Se on SARS-CoV-2 Virus Replication
Details   In Vitro study of a humic substance containing vitamin C, selemium ions, and zinc ions, showing 50% SARS-CoV-2 inhibition at picomolar concentrations.
Feb 24
Review Kory et al., Journal of Clinical Medicine Research, doi:10.14740/jocmr4658 (Review)
“MATH+” Multi-Modal Hospital Treatment Protocol for COVID-19 Infection: Clinical and Scientific Rationale
Details   Review of the data supporting the MATH+ hospital treatment protocol for COVID-19.
Feb 11
Late Gavrielatou et al., Frontiers in Medicine, doi:10.3389/fmed.2022.814587
death, ↓58.0%, p=0.11
Effect of Vitamin C on Clinical Outcomes of Critically Ill Patients With COVID-19: An Observational Study and Subsequent Meta-Analysis
Details   Retrospective 113 consecutive mechanically ventilated COVID+ ICU patients in Greece, 10 receiving high dose IV vitamin C, showing lower mortality with treatment, without statistical significance (p=0.11). The associated meta analysis incl..
Jan 29
PrEPPEP Mohajeri et al., Mediterranean Journal of Nutrition and Metabolism, doi:10.3233/MNM-211521 The difference in the dietary inflammatory index, functional food, and antioxidants intake between COVID -19 patients and healthy persons
Details   Retrospective dietary survey analysis of 500 COVID-19 patients and 500 healthy matched controls in Iran, showing dietary inflammatory index associated with increased risk of COVID-19. IR.ARUMS.REC.1400.008.
Jan 29
PrEPPEP Mohajeri et al., Mediterranean Journal of Nutrition and Metabolism, doi:10.3233/MNM-211521 The difference in the dietary inflammatory index, functional food, and antioxidants intake between COVID -19 patients and healthy persons
Details   Retrospective dietary survey analysis of 500 COVID-19 patients and 500 healthy matched controls in Iran, showing that COVID-19 patients had lower daily consumption of vitamin C, vitamin D, vitamin E, zinc, and selenium. IR.ARUMS.REC.1400...
Jan 21
In Vitro Goc et al., European Journal of Microbiology and Immunology, doi:10.1556/1886.2021.00022 (In Vitro)
In Vitro
Inhibitory effects of specific combination of natural compounds against SARS-CoV-2 and its Alpha, Beta, Gamma, Delta, Kappa, and Mu variants
Details   In Vitro study testing combinations of plant extracts and micronutrients with several variants of SARS-CoV-2. A combination of vitamin C, N-acetylcysteine, curcumin, quercetin, resveratrol, theaflavin, naringenin, baicalin, and broccoli e..
Jan 15
Late Yang et al., Am. J. Transl. Res., 14:1
recov. time, ↓15.4%, p=0.15
Traditional Chinese medicine together with high-dose vitamin C improves the therapeutic effect of western medicine against COVID-19
Details   Prospective study of 60 patients in China with three arms: SOC, SOC+TCM, and SOC+TCM+high dose vitamin C, showing successively faster recovery with the addition of TCM and the addition of high dose vitamin C. TCM included low dose vitamin..
Jan 13
Late Tu et al., Infectious Diseases & Immunity, doi:10.1097/ID9.0000000000000037
death, ↓83.0%, p<0.0001
Risk Factors for Severity and Mortality in Adult Patients Confirmed with COVID-19 in Sierra Leone: A Retrospective Study
Details   Retrospective 180 hospitalized COVID-19 patients in Sierra Leone, showing lower mortality with vitamin C treatment in unadjusted results.
Dec 28
Late Baguma et al., Research Square, doi:10.21203/ (Preprint)
death, ↑48.5%, p=0.54
Characteristics of the COVID-19 patients treated at Gulu Regional Referral Hospital, Northern Uganda: A cross-sectional study
Details   Retrospective COVID+ hospitalized patients in Uganda, 385 patients receiving vitamin C treatment, showing higher mortality with treatment, without statistical significance.
Dec 15
Late Majidi et al., Frontiers in Immunology, doi:10.3389/fimmu.2021.717816
death, ↓13.6%, p=0.03
The Effect of Vitamin C on Pathological Parameters and Survival Duration of Critically Ill Coronavirus Disease 2019 Patients: A Randomized Clinical Trial
Details   RCT 100 ICU patients in Iran, 31 treated with vitamin C, showing lower mortality with treatment. IRCT20151226025699N5.
Dec 14
Ex Vivo Amssayef et al., Cardiovascular & Hematological Disorders-Drug Targets, doi:10.2174/1871529X21666211214153308 (Ex Vivo)
Ex Vivo
Vitamin C inhibits Angiotensin-Converting Enzyme-2 in Isolated Rat Aortic Ring
Details   Ex Vivo study showing vitamin C inhibiting vascular ACE2.
Nov 25
Early Ried et al., Cureus, doi:10.7759/cureus.19902
no recov., ↓30.6%, p=0.008
Therapies to Prevent Progression of COVID-19, Including Hydroxychloroquine, Azithromycin, Zinc, and Vitamin D3 With or Without Intravenous Vitamin C: An International, Multicenter, Randomized Trial
Details   RCT 237 patients in Turkey, 162 treated with IV vitamin C in addition to HCQ/AZ/zinc/vitamin D used for all patients, showing significantly faster recovery with the addition of IV vitamin C. 97% of patients were vitamin D deficient, and l..
Nov 14
Late Beigmohammadi et al., Trials, doi:10.1186/s13063-021-05795-4
death, ↓88.9%, p=0.11
The effect of supplementation with vitamins A, B, C, D, and E on disease severity and inflammatory responses in patients with COVID-19: a randomized clinical trial
Details   Small RCT 60 ICU patients in Iran, 30 treated with vitamins A, B, C, D, and E, showing significant improvement in SOFA score and several inflammatory markers at day 7 with treatment. 5,000 IU vitamin A daily, 600,000 IU vitamin D once, 30..
Nov 8
Late Tehrani et al., Urology Journal, doi:10.22037/uj.v18i.6863
death, ↓87.1%, p=0.13
An investigation into the Effects of Intravenous Vitamin C on Pulmonary CT Findings and Clinical Outcomes of Patients with COVID 19 Pneumonia A Randomized Clinical Trial
Details   RCT 54 late stage patients, 18 treated with IV vitamin C (2g every 6h for 5 days), showing significant relative improvements in oxygen saturation and respiratory rate.
Oct 28
Late Shousha et al., World Journal of Gastroenterology, doi:10.3748/wjg.v27.i40.6951
death, ↓94.2%, p=0.003
Hepatic and gastrointestinal disturbances in Egyptian patients infected with coronavirus disease 2019: A multicentre cohort study
Details   Retrospective 547 hospitalized COVID+ patients in Egypt, showing lower mortality with vitamin C treatment. Treatment was applied according to the official guidelines, indicating that vitamin C was co-administered with HCQ. Actual treatmen..
Oct 25
Late Leal-Martínez et al., International Journal of Environmental Research and Public Health, doi:10.3390/ijerph19031172 (date from earlier preprint)
death, ↓85.7%, p=0.03
Effect of a Nutritional Support System to Increase Survival and Reduce Mortality in Patients with COVID-19 in Stage III and Comorbidities: A Blinded Randomized Controlled Clinical Trial
Details   80 patient RCT with 40 patients treated with a comprehensive regimen of nutritional support, showing significantly lower mortality with treatment. Treatment contained cholecalciferol, vitamin C, zinc, spirulina maxima, folic acid, glutami..
Oct 20
PrEPPEP Deschasaux-Tanguy et al., European Journal of Public Health, doi:10.1093/eurpub/ckab165.243 Nutritional risk factors for SARS-CoV-2 infection: prospective study from the NutriNet-Santé cohort
Details   Analysis of 7,766 adults in France, showing higher intakes of vitamin C, folates, vitamin K, dietary fibre, and fruit and vegetables associated with a lower seroprevalence of anti-SARS-CoV-2 antibodies.
Sep 27
Late Simsek et al., Annals of Medical Research, doi:10.5455/annalsmedres.2020.10.1043
death, ↓44.1%, p=0.18
Effects of high dose vitamin C administration in Covid-19 patients
Details   Retrospective 139 hospitalized patients in Turkey, 58 treated with high dose vitamin C, showing improved kidney functioning with treatment. Mortality was lower with treatment, but not reaching statistical significance with the small sampl..
Sep 22
Late Zheng et al., Open Medicine, doi:10.1515/med-2021-0361
death, ↑157.0%, p=0.33
No significant benefit of moderate-dose vitamin C on severe COVID-19 cases
Details   Retrospective 397 severe COVID-19 patients in China, showing worse outcomes with vitamin C treatment, without statistical significance. IV vitamin C 2-4g/day. Subject to confounding by indication and immortal time bias. Exclusion criteria..
Sep 7
Late Xia et al., Aging, doi:10.18632/aging.203503 High-dose vitamin C ameliorates cardiac injury in COVID-19 pandemic: a retrospective cohort study
Details   Retrospective 113 severe and critical patients in China with cardiac injury, 51 treated with high dose vitamin C, showing treatment associated with improvement of myocardial injury.
Aug 17
Late Capone et al., Cureus, doi:10.7759/cureus.9809 Characterization of Critically Ill COVID-19 Patients at a Brooklyn Safety-Net Hospital
Details   Retrospective 102 ICU patients in the USA, 73 receiving vitamin C and zinc, showing a negative correlation of treatment with mortality, but not reaching statistical significance (p = 0.31).
Aug 4
PrEPPEP Mohseni et al., Nutrition & Food Science, doi:10.1108/NFS-11-2020-0421
cases, ↑44.2%, p=0.002
Do body mass index (BMI) and history of nutritional supplementation play a role in the severity of COVID-19? A retrospective study
Details   Retrospective 603 patients in Iran, 34 taking vitamin C supplements, showing increased risk of COVID-19 cases in unadjusted results. IR.SHOUSHTAR.REC.1399.015.
Jul 26
Late Tan et al., QJM, doi:10.1093/qjmed/hcab184
death/int., ↓24.5%, p=0.74
Efficacy of diammonium glycyrrhizinate combined with vitamin C for treating hospitalized COVID-19 patients: a retrospective, observational stud
Details   PSM retrospective 207 hospitalized patients in China, 46 treated with diammonium glycyrrhizinate and vitamin C, showing lower risk of ARDS with treatment.
Jul 9
Early Rabail et al., Food Science & Nutrition, doi:10.1002/fsn3.2458 Nutritional and lifestyle changes required for minimizing the recovery period in home quarantined COVID-19 patients of Punjab, Pakistan
Details   Survey of 80 recovered COVID-19 patients in Pakistan, showing faster recovery with vitamin C, vitamin D, and zinc supplementation.
Jul 6
PrEPPEP Margolin et al., Journal of Evidence-Based Integrative Medicine, doi:10.1177/2515690X211026193
cases, ↓94.4%, p=0.003
20-Week Study of Clinical Outcomes of Over-the-Counter COVID-19 Prophylaxis and Treatment
Details   Retrospective 113 outpatients, 53 (patient choice) treated with zinc, quercetin, vitamin C/D/E, l-lysine, and quina, showing lower cases with treatment. Results are subject to selection bias and limited information on the groups is provid..
Jul 4
Late Özgünay et al., The European Research Journal, doi:10.18621/eurj.938778
death, ↓9.3%, p=0.69
The use of vitamin C in the intensive care unit during the COVID-19 pandemic
Details   Retrospective 160 ICU patients, 32 with raised neutrophil/lymphocyte ratio treated with vitamin C, showing no significant differences.
Jun 30
Late Vishnuram et al., Indian Journal of Basic and Applied Medical Research, doi:10.36848/IJBAMR/2020/29215.55599
death, ↓54.2%, p=0.03
Role of high dose oral liposomal vitamin C in reducing mortality in patients with COVID-19
Details   Retrospective 8,634 hospitalized patients in India, showing lower mortality with high-dose vitamin C in unadjusted results. No group details are provided, the text and table appear to show different results, and some numbers do not match.
Jun 8
Late Li et al., Journal of Pharmacy Practice, doi:10.1177/08971900211015052
death, ↑10.5%, p=1.00
Use of Intravenous Vitamin C in Critically Ill Patients With COVID-19 Infection
Details   PSM retrospective 8 ICU patients treated with vitamin C and 24 matched controls, showing no significant difference. Authors note that "it is possible for the delayed timing of IV vitamin C to have blunted the beneficial effects as th..
Jun 1
Review May et al., British Journal of Pharmacology, doi:10.1111/bph.15579 (Review)
Therapeutic potential of megadose vitamin C to reverse organ dysfunction in sepsis and COVID-19
Details   Review of data supporting the use of megadose vitamin C as a treatment for sepsis and COVID-19.
May 26
Late Pourhoseingholi et al., Research Square, doi:10.21203/ (Preprint)
death, ↓13.0%, p=0.38
Case Characteristics, Clinical Data, And Outcomes of Hospitalized COVID-19 Patients In Qom Province, Iran: A Prospective Cohort Study
Details   Prospective study of 2,468 hospitalized COVID-19 patients in Iran, showing no significant difference with vitamin C treatment. IR.MUQ.REC.1399.013.
May 11
PrEPPEP Aldwihi et al., International Journal of Environmental Research and Public Health, doi:10.3390/ijerph18105086
hosp., ↓36.3%, p=0.006
Patients’ Behavior Regarding Dietary or Herbal Supplements before and during COVID-19 in Saudi Arabia
Details   Retrospective survey-based analysis of 738 COVID-19 patients in Saudi Arabia, showing lower hospitalization with vitamin C, turmeric, zinc, and nigella sativa, and higher hospitalization with vitamin D. For vitamin D, most patients contin..
May 11
Late Suna et al., Med. Clin. (Barc.), doi:10.1016/j.medcli.2021.04.010
death, ↓21.3%, p=0.52
Effect of high-dose intravenous vitamin C on prognosis in patients with SARS-CoV-2 pneumonia
Details   Retrospective 323 hospitalized patients, 153 treated with vitamin C, showing no significant differences. Patients in each group were in different time periods, with the vitamin C group first. Time based confounding is possible due to impr..
May 3
In Silico Malla et al., bioRxiv, doi:10.1101/2021.05.02.442358 (Preprint)
In Silico
Vitamin C inhibits SARS coronavirus-2 main protease essential for viral replication
Details   In Vitro study showing that vitamin C inhibits SARS-CoV-2 3CLpro. Authors note that the different clinical results may be explained in part by the widely varying dosages used, and they conclude that vitamin C and/or derivatives may become..
Apr 30
Late Elhadi et al., PLOS ONE, doi:10.1371/journal.pone.0251085
death, ↑12.0%, p=0.15
Epidemiology, outcomes, and utilization of intensive care unit resources for critically ill COVID-19 patients in Libya: A prospective multi-center cohort study
Details   Prospective study of 465 COVID-19 ICU patients in Libya showing no significant differences with treatment.
Apr 22
Early Zhao et al., Frontiers in Pharmacology, doi:10.3389/fphar.2021.638556
progression, ↓72.0%, p=0.03
High Dose Intravenous Vitamin C for Preventing The Disease Aggravation of Moderate COVID-19 Pneumonia. A Retrospective Propensity Matched Before-After Study
Details   PSM retrospective 110 patients, 55 treated with high-dose IV vitamin C, showing lower progression to severe disease with treatment. Patients in each group were in different time periods, time based confounding is likely due to SOC improvi..
Apr 14
Late Hakamifard et al., Immunopathologia Persa, doi:10.34172/ipp.2021.xx
ICU, ↓46.3%, p=0.46
The effect of vitamin E and vitamin C in patients with COVID-19 pneumonia; a randomized controlled clinical trial
Details   RCT with 38 patients treated with vitamin C and vitamin E, and 34 control patients, showing lower ICU admission with treatment, but not statistically significant.
Apr 8
PrEPPEP Abdulateef et al., Open Medicine, doi:10.1515/med-2021-0273
hosp., ↓18.7%, p=0.69
COVID-19 severity in relation to sociodemographics and vitamin D use
Details   Survey of 428 recovered COVID-19 patients in Iraq, showing fewer hospital visits for patients on prophylactic vitamin C or D. Hospitalization was lower for those on vitamin C, D, or zinc, without statistical significance.
Apr 8
Late Gadhiya et al., BMJ Open, doi:10.1136/bmjopen-2020-042549
death, ↑0.7%, p=0.98
Clinical characteristics of hospitalised patients with COVID-19 and the impact on mortality: a single-network, retrospective cohort study from Pennsylvania state
Details   Retrospective 283 patients in the USA showing higher mortality with all treatments (not statistically significant). Confounding by indication is likely. In the supplementary appendix, authors note that the treatments were usually given fo..
Apr 7
Late Mulhem et al., BMJ Open, doi:10.1136/bmjopen-2020-042042
death, ↑32.2%, p=0.01
3219 hospitalised patients with COVID-19 in Southeast Michigan: a retrospective case cohort study
Details   Retrospective database analysis of 3,219 hospitalized patients in the USA. Very different results in the time period analysis (Table S2), and results significantly different to other studies for the same medications (e.g., heparin OR 3.06..
Apr 2
Late Al Sulaiman et al., Research Square, doi:10.21203/ (Preprint)
death, ↓14.9%, p=0.27
Ascorbic Acid as an Adjunctive Therapy in Critically Ill Patients with COVID-19: A Multicenter Propensity Score Matched Study
Details   Retrospective 158 critically ill patients receiving vitamin C and propensity matched controls, showing mortality OR 0.77 [0.48-1.23], and statistically significantly lower thrombosis, OR 0.42 [0.18-0.94]. 1000mg of vitamin C was given dai..
Mar 30
PrEPPEP Holt et al., Thorax, doi:10.1136/thoraxjnl-2021-217487
cases, ↑2.9%, p=0.86
Risk factors for developing COVID-19: a population-based longitudinal study (COVIDENCE UK)
Details   Prospective survey-based study with 15,227 people in the UK, showing lower risk of COVID-19 cases with vitamin A, vitamin D, zinc, selenium, probiotics, and inhaled corticosteroids; and higher risk with metformin and vitamin C. Statistica..
Mar 8
Late Hamidi-Alamdari et al., Clinical and Translational Investigation, doi:10.24875/RIC.21000028
death, ↓44.4%, p=0.38
Methylene blue for treatment of hospitalized COVID-19 patients: a randomized, controlled, open-label clinical trial, phase 2
Details   RCT 80 hospitalized patients with severe COVID-19, 40 treated with methylene blue + vitamin C + N-acetylcysteine, showing lower mortality, shorter hospitalization, and significantly improved SpO2 and respiratory distress with treatment. N..
Mar 2
Early Hemilä et al., Research Square, doi:10.21203/ (Preprint) (meta analysis)
Vitamin C may increase the recovery rate of outpatient cases of SARS-CoV-2 infection by 70%: reanalysis of the COVID A to Z Randomized Clinical Trial
Details   Reanalysis of Thomas et al. showing that vitamin C increased the recovery rate by 70%, p = 0.025.
Feb 26
Late Gao et al., Aging, doi:10.18632/aging.202557
death, ↓86.0%, p=0.04
The efficiency and safety of high-dose vitamin C in patients with COVID-19: a retrospective cohort study
Details   Retrospective 76 COVID-19 patients, 46 treated with intravenous high-dose vitamin C, showing lower mortality and improved oxygen requirements with treatment. Dosage was 6g intravenous infusion per 12hr on the first day, and 6g once for th..
Feb 15
PrEPPEP Mahto et al., American Journal of Blood Research, 11:1
IgG+, ↑25.9%, p=0.49
Seroprevalence of IgG against SARS-CoV-2 and its determinants among healthcare workers of a COVID-19 dedicated hospital of India
Details   Retrospective 689 healthcare workers in India, showing no significant difference in IgG positivity with vitamin C prophylaxis.
Feb 12
Early Thomas et al., JAMA Network Open, doi:10.1001/jamanetworkopen.2021.0369
death, ↑204.2%, p=0.49
Effect of High-Dose Zinc and Ascorbic Acid Supplementation vs Usual Care on Symptom Length and Reduction Among Ambulatory Patients With SARS-CoV-2 Infection: The COVID A to Z Randomized Clinical Trial
Details   Small 214 low-risk outpatient RCT showing non-statistically significant faster recovery with zinc and with vitamin C. NCT04342728. A secondary analysis concludes that vitamin C increases recovery rate by 71% (p = 0.036) . See also .
Feb 9
PrEPPEP Hancock et al., SSRN, doi:10.2139/ssrn.3779211 (Preprint) Case Cluster of RT-PCR COVID-19 Positive Patients with an Unexpected Benign Clinical Course With Vitamin D, Melatonin, Vitamin C, and Viscum Album
Details   Case series of 24 COVID-19 patients (12 confirmed PCR+) treated with vitamin D, vitamin C, and melatonin, showing positive outcomes with no patient having worse than a mild case, including 7 high risk patients.
Feb 1
Levels Muhammad et al., SAGE Open Medicine, doi:10.1177/2050312121991246 Deficiency of antioxidants and increased oxidative stress in COVID-19 patients: A cross-sectional comparative study in Jigawa, Northwestern Nigeria
Details   Case control study with 50 symptomatic COVID-19 patients and 21 healthy controls in Nigeria, showing that COVID-19 patients had significantly lower levels of selenium and zinc, and vitamins A, C, and E. Control patients were younger than ..
Feb 1
Late Zhao et al., Ann. Palliat. Med., doi:10.21037/apm-20-1387 Beneficial aspects of high dose intravenous vitamin C on patients with COVID-19 pneumonia in severe condition: a retrospective case series study
Details   Retrospective case study of 12 severe/critical COVID-19 patients finding that high dose IV vitamin C improved inflammatory response, immune and organ function. There was no control group.
Jan 27
Late Xing et al., Journal of Pharmaceutical and Biomedical Analysis, doi:10.1016/j.jpba.2021.113927 Vitamin C supplementation is necessary for patients with coronavirus disease: An ultra-high-performance liquid chromatography-tandem mass spectrometry finding
Details   Prospective study with 31 COVID-19 patients and 60 controls reporting on a new method to assess plasma vitamin C concentrations. Vitamin C was deficient (11.4µmol/l vs. 52µmol/l for healthy controls), and returned to a normal range (76µmo..
Jan 18
Review Hemilä et al., Frontiers in Medicine, doi:10.3389/fmed.2020.559811 (Review)
Vitamin C and COVID-19
Details   Review of the use of vitamin C for infections and the potential benefit for COVID-19.
Jan 9
Late JamaliMoghadamSiahkali et al., Research Square, doi:10.21203/ (Preprint)
death, 0.0%, p=1.00
Safety and Effectiveness of High-Dose Vitamin C in Patients with COVID-19; A Randomized Controlled open-label Clinical Trial
Details   Small late stage RCT for the addition of vitamin C to HCQ and lopinavir/ritonavir, with 30 treatment and 30 control patients, finding a significant reduction in temperature and a significant improvement in oxygenation after 3 days in the ..
Dec 23
Early Su et al., BioScience Trends, doi:10.5582/bst.2020.03340
progression, ↑135.3%, p=0.18
Efficacy of early hydroxychloroquine treatment in preventing COVID-19 pneumonia aggravation, the experience from Shanghai, China
Details   Retrospective 616 patients in China showing increased risk of disease progression for vitamin C treatment within five days.
Dec 16
Late Jang et al., Heart & Lung, doi:10.1016/j.hrtlng.2020.10.010
no recov., ↓51.4%, p=0.15
Clinical course of COVID-19 patients treated with ECMO: A multicenter study in Daegu, South Korea
Details   Retrospective 19 COVID-19 ECMO patients in South Korea, showing a higher rate of weaning from ECMO with vitamin C treatment, without statistical significance. Authors perform multivariate analysis but do not provide full results, only rep..
Dec 15
Late Darban et al., Journal of Cellular & Molecular Anesthesia, doi:10.22037/jcma.v6i2.32182
progression, ↓33.3%, p=1.00
Efficacy of High Dose Vitamin C, Melatonin and Zinc in Iranian Patients with Acute Respiratory Syndrome due to Coronavirus Infection: A Pilot Randomized Trial
Details   Small RCT in Iran with 20 ICU patients, 10 treated with high-dose vitamin C, melatonin, and zinc, not showing significant differences. IRCT20151228025732N52.
Dec 10
Late Rosenthal et al., JAMA Network Open, doi:10.1001/jamanetworkopen.2020.29058
death, ↓11.0%, p=0.005
Risk Factors Associated With In-Hospital Mortality in a US National Sample of Patients With COVID-19
Details   Retrospective database analysis of 64,781 hospitalized patients in the USA, showing lower mortality with vitamin C or vitamin D (authors do not distinguish between the two), and higher mortality with zinc and HCQ, statistically significan..
Dec 7
Review Holford et al., Nutrients, doi:10.3390/nu12123760 (Review)
Vitamin C—An Adjunctive Therapy for Respiratory Infection, Sepsis and COVID-19
Details   Review of vitamin C use for respiratory infections including COVID-19 and the mechanisms of action. Authors note that evidence to date indicates oral vitamin C (2–8 g/day) may reduce the incidence and duration of respiratory infections, a..
Nov 30
Late Kumari et al., Cureus 12(11): e11779, doi:10.7759/cureus.11779
death, ↓36.4%, p=0.45
The Role of Vitamin C as Adjuvant Therapy in COVID-19
Details   RCT 150 hospitalized patients in Pakistan showing 26% faster recovery, p < 0.0001. 36% lower mortality, not statistically significant due to the small number of events. Dosage was 50 mg/kg/day of intravenous vitamin C.
Nov 30
PrEPPEP Louca et al., BMJ Nutrition, Prevention & Health, doi:10.1136/bmjnph-2021-000250 (date from earlier preprint)
cases, 0.0%, p=1.00
Modest effects of dietary supplements during the COVID-19 pandemic: insights from 445 850 users of the COVID-19 Symptom Study app
Details   Survey analysis of dietary supplements showing no significant difference in PCR+ cases with vitamin C usage in the UK, however significant reductions were found in the US and Sweden. These results are for PCR+ cases only, they do not refl..
Nov 3
PrEPPEP Behera et al., PLoS ONE, doi:10.1371/journal.pone.0247163 (date from earlier preprint)
cases, ↓18.0%, p=0.58
Role of ivermectin in the prevention of SARS-CoV-2 infection among healthcare workers in India: A matched case-control study
Details   Retrospective matched case-control prophylaxis study for HCQ, ivermectin, and vitamin C with 372 healthcare workers, showing lower COVID-19 incidence for all treatments, with statistical significance reached for ivermectin. HCQ OR 0.56, p..
Oct 1
Late Patel et al., Chest Infections, doi:10.1016/j.chest.2020.08.322
death, ↓29.5%, p=0.18
The significance of oral ascorbic acid in patients with COVID-19
Details   Retrospective 176 hospitalized patients, 96 treated with oral vitamin C (from 500mg to 1500mg daily), showing lower mortality with treatment.
Sep 20
Late Yüksel et al., Intensive Care Medicine Experimental, 9:S1, 001458, doi:10.1186/s40635-021-00413-8 (Preprint)
death, ↓18.8%, p=0.04
Effects of high dose vitamin c on patient outcomes in ARDS patients admitted to intensive care with COVID-19; multi-center retrospective study
Details   PSM retrospective 86 ICU patients on mechanical ventilation in Turkey, showing lower mortality with high dose vitamin C treatment (≥200mg/kg for 4 days).
Sep 8
Levels Arvinte et al., Med. Drug Discov, doi:10.1016/j.medidd.2020.100064 Serum Levels of Vitamin C and Vitamin D in a Cohort of Critically Ill COVID-19 Patients of a North American Community Hospital Intensive Care Unit in May 2020: A Pilot Study
Details   Pilot study with 21 ICU patients finding low serum levels of vitamin C and vitamin D in most patients. Older age and low vitamin C level appeared to be co-dependent risk factors for mortality.
Sep 8
PrEPPEP Galmés et al., Nutrients, doi:10.3390/nu12092738 Current State of Evidence: Influence of Nutritional and Nutrigenetic Factors on Immunity in the COVID-19 Pandemic Framework
Details   Ecological study of European countries analyzing 10 vitamins and minerals endorsed by the European Food Safety Authority as having sufficient evidence for a causal relationship between intake and optimal immune system function: vitamins D..
Aug 26
Levels Chiscano-Camón et al., Critical Care, doi:10.1186/s13054-020-03249-y Vitamin C levels in patients with SARS-CoV-2-associated acute respiratory distress syndrome
Details   Small study of 18 COVID-19 ARDS patients showing that vitamin C levels were very low - 17 patients had undetectable levels and one had a low level (2.4 mg/L).
Aug 10
Late Zhang et al., Annals of Intensive Care, doi:10.1186/s13613-020-00792-3
death, ↓50.0%, p=0.20
Pilot Trial of High-dose vitamin C in critically ill COVID-19 patients (preprint 8/10/2020)
Details   Small RCT for high dose vitamin C for ICU patients showing reduced (but not statistically significant) mortality. Dosage was 12g of vitamin C/50ml every 12 hours for 7 days at a rate of 12ml/hour.
Aug 1
Late Hiedra et al., Expert Review of Anti-infective Therapy, doi:10.1080/14787210.2020.1794819 The use of IV vitamin C for patients with COVID-19: a case series
Details   Case study of 17 patients receiving IV vitamin C for COVID-19, finding a significant decrease in inflammatory markers, including ferritin and D-dimer, and a trend to decreasing FiO2 requirements, after vitamin C administration. There was ..
Jul 25
Review Feyaerts et al., Nutrition, doi:10.1016/j.nut.2020.110948 (Review)
Vitamin C as prophylaxis and adjunctive medical treatment for COVID-19?
Details   Review concluding that there is clear evidence that vitamin C in high doses can reduce interleukin-6 and endothelin-1 mediators. Authors suggest a relatively low dose as prophylaxis, and in cases of severe COVID-19, an (intravenous) high-..
Jul 20
Late Krishnan et al., J Clin Anesth., doi:10.1016/j.jclinane.2020.110005
death, ↓30.7%, p=0.04
Clinical comorbidities, characteristics, and outcomes of mechanically ventilated patients in the State of Michigan with SARS-CoV-2 pneumonia
Details   Retrospective 152 mechanically ventilated patients in the USA showing unadjusted lower mortality with vitamin C, vitamin D, HCQ, and zinc treatment, statistically significant only for vitamin C.
Jun 19
Review Biancatelli et al., Frontiers in Immunology, doi:10.3389/fimmu.2020.01451 (Review)
Quercetin and Vitamin C: An Experimental, Synergistic Therapy for the Prevention and Treatment of SARS-CoV-2 Related Disease (COVID-19)
Details   Review of the evidence for the use of vitamin C and quercetin both for prophylaxis in high-risk populations and for the treatment of COVID-19 patients.
May 27
In Silico Kumar et al., VirusDisease, doi:10.1007/s13337-020-00643-6 (date from earlier preprint)
In Silico
In silico virtual screening-based study of nutraceuticals predicts the therapeutic potentials of folic acid and its derivatives against COVID-19
Details   In Silico analysis finding that magnesium ascorbate, a form of Vitamin C, was found to be the top compound among 106 nutraceuticals for binding to Mpro of SARS-CoV-2.
Please send us corrections, updates, or comments. Vaccines and treatments are both valuable and complementary. All practical, effective, and safe means should be used. No treatment, vaccine, or intervention is 100% available and effective for all current and future variants. Denying the efficacy of any method increases mortality, morbidity, collateral damage, and the risk of endemic status. We do not provide medical advice. Before taking any medication, consult a qualified physician who can provide personalized advice and details of risks and benefits based on your medical history and situation. FLCCC and WCH provide treatment protocols.
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