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Vitamin C for COVID-19: real-time meta analysis of 42 studies
Covid Analysis, May 17, 2022, DRAFT
https://c19vitaminc.com/meta.html
0 0.5 1 1.5+ All studies 18% 42 39,120 Improvement, Studies, Patients Relative Risk Mortality 25% 27 19,087 Ventilation 18% 4 470 ICU admission 15% 5 654 Hospitalization 14% 8 3,079 Recovery 23% 5 571 Cases -8% 4 15,830 Viral clearance 10% 2 130 RCTs 20% 12 1,003 RCT mortality 17% 7 588 Peer-reviewed 20% 36 35,616 High dose IV 21% 16 1,726 Symptomatic 24% 38 23,290 Prophylaxis -3% 8 19,347 Early 43% 3 445 Late 25% 31 19,328 Vitamin C for COVID-19 c19vitaminc.com May 2022 Favorsvitamin C Favorscontrol after exclusions
Statistically significant improvements are seen for mortality, ICU admission, progression, and recovery. 14 studies from 14 independent teams in 7 different countries show statistically significant improvements in isolation (7 for the most serious outcome).
Meta analysis using the most serious outcome reported shows 18% [8‑27%] improvement. Results are similar for Randomized Controlled Trials, similar after exclusions, and similar for peer-reviewed studies. Clinical outcomes suggest benefit while viral and case outcomes do not, consistent with an intervention that aids recovery but is not antiviral. Early treatment is more effective than late treatment.
0 0.5 1 1.5+ All studies 18% 42 39,120 Improvement, Studies, Patients Relative Risk Mortality 25% 27 19,087 Ventilation 18% 4 470 ICU admission 15% 5 654 Hospitalization 14% 8 3,079 Recovery 23% 5 571 Cases -8% 4 15,830 Viral clearance 10% 2 130 RCTs 20% 12 1,003 RCT mortality 17% 7 588 Peer-reviewed 20% 36 35,616 High dose IV 21% 16 1,726 Symptomatic 24% 38 23,290 Prophylaxis -3% 8 19,347 Early 43% 3 445 Late 25% 31 19,328 Vitamin C for COVID-19 c19vitaminc.com May 2022 Favorsvitamin C Favorscontrol after exclusions
The treatment regimen varies widely across studies and may be high-dose IV vitamin C.
While many treatments have some level of efficacy, they do not replace vaccines and other measures to avoid infection. Only 2% of vitamin C studies show zero events in the treatment arm. Multiple treatments are typically used in combination, and other treatments are significantly more effective.
No treatment, vaccine, or intervention is 100% available and effective for all variants. All practical, effective, and safe means should be used. Denying the efficacy of treatments increases mortality, morbidity, collateral damage, and endemic risk.
All data to reproduce this paper and sources are in the appendix.
Highlights
Vitamin C reduces risk for COVID-19 with very high confidence for mortality, progression, recovery, and in pooled analysis, high confidence for ICU admission, and low confidence for hospitalization.
We show traditional outcome specific analyses and combined evidence from all studies, incorporating treatment delay, a primary confounding factor in COVID-19 studies.
Real-time updates and corrections, transparent analysis with all results in the same format, consistent protocol for 41 treatments.
A
0 0.25 0.5 0.75 1 1.25 1.5 1.75 2+ Thomas (RCT) -204% 3.04 [0.13-72.9] death 1/48 0/50 Improvement, RR [CI] Treatment Control Zhao (PSM) 72% 0.28 [0.08-0.93] progression 4/55 12/55 Ried (RCT) 31% 0.69 [0.54-0.89] no recov. 69/162 46/75 Tau​2 = 0.21, I​2 = 43.0%, p = 0.15 Early treatment 43% 0.57 [0.27-1.23] 74/265 58/180 43% improvement Krishnan 31% 0.69 [0.47-0.92] death 40/79 52/73 Improvement, RR [CI] Treatment Control Zhang (RCT) 50% 0.50 [0.20-1.50] death 6/27 11/29 ICU patients Yüksel (ICU) 19% 0.81 [0.66-0.99] death 31/42 40/44 ICU patients Patel 29% 0.71 [0.43-1.14] death 22/96 26/80 Kumari (RCT) 36% 0.64 [0.26-1.55] death 7/75 11/75 Darban (RCT) 33% 0.67 [0.14-3.17] progression 2/10 3/10 ICU patients CT​1 JamaliMo.. (RCT) 0% 1.00 [0.22-4.56] death 3/30 3/30 Gao 86% 0.14 [0.03-0.72] death 1/46 5/30 Hamidi-A.. (RCT) 44% 0.56 [0.20-1.51] death 5/40 9/40 CT​1 Al Sulaiman (PSM) 15% 0.85 [0.61-1.12] death 46/142 59/142 Mulhem -32% 1.32 [1.07-1.62] death 157/794 359/2,425 Gadhiya -1% 1.01 [0.48-1.91] death 19/55 36/226 Hakamifard (RCT) 46% 0.54 [0.14-2.08] ICU 3/38 5/34 CT​1 Elhadi (ICU) -12% 1.12 [0.96-1.31] death 175/277 106/188 ICU patients Suna 21% 0.79 [0.44-1.41] death 17/153 24/170 Pourhoseingholi 13% 0.87 [0.63-1.19] death 54/199 285/2,269 Li (ICU) -11% 1.11 [0.79-1.54] death 7/8 19/24 ICU patients Vishnuram 54% 0.46 [0.24-0.86] death 164/8,634 10/241 Özgünay (ICU) 9% 0.91 [0.63-1.30] death 17/32 75/128 ICU patients Tan 25% 0.75 [0.10-2.98] death/int. 1/46 14/115 CT​1 Zheng (PSM) -157% 2.57 [0.39-16.8] death 12/70 7/327 Simsek 44% 0.56 [0.23-1.35] death 6/58 15/81 Shousha 94% 0.06 [0.01-0.37] death 22/340 31/207 Tehrani (RCT) 87% 0.13 [0.01-2.25] death 0/18 4/26 Majidi (DB RCT) 14% 0.86 [0.74-1.01] death 26/31 67/69 ICU patients Baguma -48% 1.48 [0.41-4.70] death 385 (n) 96 (n) Yang (RCT) 15% 0.85 [0.68-1.06] recov. time 10 (n) 10 (n) LD​2 Gavrielatou (ICU) 58% 0.42 [0.12-1.48] death 2/10 49/103 ICU patients Salehi (ICU) 10% 0.90 [0.65-1.25] death 22/40 52/85 ICU patients Coppock (RCT) 5% 0.95 [0.16-7.84] progression 4/44 2/22 Hess (IPW) 20% 0.80 [0.40-1.60] death 10/25 37/75 Tau​2 = 0.15, I​2 = 81.8%, p = 0.0019 Late treatment 25% 0.75 [0.63-0.90] 881/11,854 1,416/7,474 25% improvement Behera 18% 0.82 [0.45-1.57] cases case control Improvement, RR [CI] Treatment Control Louca 0% 1.00 [0.97-1.04] cases Mahto -26% 1.26 [0.63-2.28] IgG+ 34/140 59/549 Holt -3% 1.03 [0.77-1.39] cases 49/1,580 397/13,647 Abdulateef 19% 0.81 [0.37-1.78] hosp. 8/132 22/295 Mohseni -44% 1.44 [1.22-1.71] cases 34/43 307/560 Nimer 25% 0.75 [0.54-1.04] hosp. 52/651 167/1,497 Shehab 4% 0.96 [0.46-1.99] severe case 14/139 12/114 Tau​2 = 0.03, I​2 = 70.2%, p = 0.74 Prophylaxis -3% 1.03 [0.87-1.22] 191/2,685 964/16,662 -3% improvement All studies 18% 0.82 [0.73-0.92] 1,146/14,804 2,438/24,316 18% improvement 42 vitamin C COVID-19 studies c19vitaminc.com May 2022 Tau​2 = 0.07, I​2 = 80.7%, p = 0.00096 Effect extraction pre-specified(most serious outcome, see appendix) 1 CT: study uses combined treatment2 LD: comparison with low dose treatment Favors vitamin C Favors control
Figure 1. A. Random effects meta-analysis. This plot shows pooled effects, discussion can be found in the heterogeneity section, and results for specific outcomes can be found in the individual outcome analyses. Effect extraction is pre-specified, using the most serious outcome reported. For details of effect extraction see the appendix. B. Scatter plot showing the distribution of effects reported in studies. C. History of all reported effects (chronological within treatment stages).
Introduction
We analyze all significant studies concerning the use of vitamin C for COVID-19. Search methods, inclusion criteria, effect extraction criteria (more serious outcomes have priority), all individual study data, PRISMA answers, and statistical methods are detailed in Appendix 1. We present random effects meta-analysis results for all studies, for studies within each treatment stage, for individual outcomes, for peer-reviewed studies, for Randomized Controlled Trials (RCTs), and after exclusions.
Figure 2 shows stages of possible treatment for COVID-19. Prophylaxis refers to regularly taking medication before becoming sick, in order to prevent or minimize infection. Early Treatment refers to treatment immediately or soon after symptoms appear, while Late Treatment refers to more delayed treatment.
Figure 2. Treatment stages.
Preclinical Research
3 In Silico studies support the efficacy of vitamin C [Kumar, Malla, Pandya].
An In Vitro study supports the efficacy of vitamin C [Goc].
Preclinical research is an important part of the development of treatments, however results may be very different in clinical trials. Preclinical results are not used in this paper.
Results
Figure 3 shows a visual overview of the results, with details in Table 1 and Table 2. Figure 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, and 15 show forest plots for a random effects meta-analysis of all studies with pooled effects, mortality results, ventilation, ICU admission, hospitalization, progression, recovery, cases, viral clearance, high dose IV studies, peer reviewed studies, and non-symptomatic vs. symptomatic results.
0 0.5 1 1.5+ ALL STUDIES MORTALITY VENTILATION ICU ADMISSION HOSPITALIZATION RECOVERY CASES VIRAL CLEARANCE RANDOMIZED CONTROLLED TRIALS RCT MORTALITY PEER-REVIEWED HIGH DOSE IV After Exclusions ALL STUDIES All Prophylaxis Early Late Vitamin C for COVID-19 C19VITAMINC.COM MAY 2022
Figure 3. Overview of results.
Treatment timeNumber of studies reporting positive effects Total number of studiesPercentage of studies reporting positive effects Random effects meta-analysis results
Early treatment 2 3 66.7% 43% improvement
RR 0.57 [0.27‑1.23]
p = 0.15
Late treatment 24 31 77.4% 25% improvement
RR 0.75 [0.63‑0.90]
p = 0.0019
Prophylaxis 4 8 50.0% -3% improvement
RR 1.03 [0.87‑1.22]
p = 0.74
All studies 30 42 71.4% 18% improvement
RR 0.82 [0.73‑0.92]
p = 0.00096
Table 1. Results by treatment stage.
Studies Early treatment Late treatment Prophylaxis PatientsAuthors
All studies 4243% [-23‑73%]25% [10‑37%]-3% [-22‑13%] 39,120 477
With exclusions 2730% [10‑46%]39% [20‑54%]5% [-13‑20%] 8,471 325
Peer-reviewed 3643% [-23‑73%]30% [12‑45%]-3% [-22‑13%] 35,616 397
Randomized Controlled TrialsRCTs 1230% [10‑46%]17% [6‑27%] 1,003 142
Table 2. Results by treatment stage for all studies and with different exclusions.
0 0.25 0.5 0.75 1 1.25 1.5 1.75 2+ Thomas (RCT) -204% 3.04 [0.13-72.9] death 1/48 0/50 Improvement, RR [CI] Treatment Control Zhao (PSM) 72% 0.28 [0.08-0.93] progression 4/55 12/55 Ried (RCT) 31% 0.69 [0.54-0.89] no recov. 69/162 46/75 Tau​2 = 0.21, I​2 = 43.0%, p = 0.15 Early treatment 43% 0.57 [0.27-1.23] 74/265 58/180 43% improvement Krishnan 31% 0.69 [0.47-0.92] death 40/79 52/73 Improvement, RR [CI] Treatment Control Zhang (RCT) 50% 0.50 [0.20-1.50] death 6/27 11/29 ICU patients Yüksel (ICU) 19% 0.81 [0.66-0.99] death 31/42 40/44 ICU patients Patel 29% 0.71 [0.43-1.14] death 22/96 26/80 Kumari (RCT) 36% 0.64 [0.26-1.55] death 7/75 11/75 Darban (RCT) 33% 0.67 [0.14-3.17] progression 2/10 3/10 ICU patients CT​1 JamaliMo.. (RCT) 0% 1.00 [0.22-4.56] death 3/30 3/30 Gao 86% 0.14 [0.03-0.72] death 1/46 5/30 Hamidi-A.. (RCT) 44% 0.56 [0.20-1.51] death 5/40 9/40 CT​1 Al Sulaiman (PSM) 15% 0.85 [0.61-1.12] death 46/142 59/142 Mulhem -32% 1.32 [1.07-1.62] death 157/794 359/2,425 Gadhiya -1% 1.01 [0.48-1.91] death 19/55 36/226 Hakamifard (RCT) 46% 0.54 [0.14-2.08] ICU 3/38 5/34 CT​1 Elhadi (ICU) -12% 1.12 [0.96-1.31] death 175/277 106/188 ICU patients Suna 21% 0.79 [0.44-1.41] death 17/153 24/170 Pourhoseingholi 13% 0.87 [0.63-1.19] death 54/199 285/2,269 Li (ICU) -11% 1.11 [0.79-1.54] death 7/8 19/24 ICU patients Vishnuram 54% 0.46 [0.24-0.86] death 164/8,634 10/241 Özgünay (ICU) 9% 0.91 [0.63-1.30] death 17/32 75/128 ICU patients Tan 25% 0.75 [0.10-2.98] death/int. 1/46 14/115 CT​1 Zheng (PSM) -157% 2.57 [0.39-16.8] death 12/70 7/327 Simsek 44% 0.56 [0.23-1.35] death 6/58 15/81 Shousha 94% 0.06 [0.01-0.37] death 22/340 31/207 Tehrani (RCT) 87% 0.13 [0.01-2.25] death 0/18 4/26 Majidi (DB RCT) 14% 0.86 [0.74-1.01] death 26/31 67/69 ICU patients Baguma -48% 1.48 [0.41-4.70] death 385 (n) 96 (n) Yang (RCT) 15% 0.85 [0.68-1.06] recov. time 10 (n) 10 (n) LD​2 Gavrielatou (ICU) 58% 0.42 [0.12-1.48] death 2/10 49/103 ICU patients Salehi (ICU) 10% 0.90 [0.65-1.25] death 22/40 52/85 ICU patients Coppock (RCT) 5% 0.95 [0.16-7.84] progression 4/44 2/22 Hess (IPW) 20% 0.80 [0.40-1.60] death 10/25 37/75 Tau​2 = 0.15, I​2 = 81.8%, p = 0.0019 Late treatment 25% 0.75 [0.63-0.90] 881/11,854 1,416/7,474 25% improvement Behera 18% 0.82 [0.45-1.57] cases case control Improvement, RR [CI] Treatment Control Louca 0% 1.00 [0.97-1.04] cases Mahto -26% 1.26 [0.63-2.28] IgG+ 34/140 59/549 Holt -3% 1.03 [0.77-1.39] cases 49/1,580 397/13,647 Abdulateef 19% 0.81 [0.37-1.78] hosp. 8/132 22/295 Mohseni -44% 1.44 [1.22-1.71] cases 34/43 307/560 Nimer 25% 0.75 [0.54-1.04] hosp. 52/651 167/1,497 Shehab 4% 0.96 [0.46-1.99] severe case 14/139 12/114 Tau​2 = 0.03, I​2 = 70.2%, p = 0.74 Prophylaxis -3% 1.03 [0.87-1.22] 191/2,685 964/16,662 -3% improvement All studies 18% 0.82 [0.73-0.92] 1,146/14,804 2,438/24,316 18% improvement 42 vitamin C COVID-19 studies c19vitaminc.com May 2022 Tau​2 = 0.07, I​2 = 80.7%, p = 0.00096 Effect extraction pre-specified(most serious outcome, see appendix) 1 CT: study uses combined treatment2 LD: comparison with low dose treatment Favors vitamin C Favors control
Figure 4. Random effects meta-analysis for all studies with pooled effects. This plot shows pooled effects, discussion can be found in the heterogeneity section, and results for specific outcomes can be found in the individual outcome analyses. Effect extraction is pre-specified, using the most serious outcome reported. For details of effect extraction see the appendix.
0 0.25 0.5 0.75 1 1.25 1.5 1.75 2+ Thomas (RCT) -204% 3.04 [0.13-72.9] 1/48 0/50 Improvement, RR [CI] Treatment Control Tau​2 = 0.00, I​2 = 0.0%, p = 0.5 Early treatment -204% 3.04 [0.13-72.9] 1/48 0/50 -204% improvement Krishnan 31% 0.69 [0.47-0.92] 40/79 52/73 Improvement, RR [CI] Treatment Control Zhang (RCT) 50% 0.50 [0.20-1.50] 6/27 11/29 ICU patients Yüksel (ICU) 19% 0.81 [0.66-0.99] 31/42 40/44 ICU patients Patel 29% 0.71 [0.43-1.14] 22/96 26/80 Kumari (RCT) 36% 0.64 [0.26-1.55] 7/75 11/75 JamaliMo.. (RCT) 0% 1.00 [0.22-4.56] 3/30 3/30 Gao 86% 0.14 [0.03-0.72] 1/46 5/30 Hamidi-A.. (RCT) 44% 0.56 [0.20-1.51] 5/40 9/40 CT​1 Al Sulaiman (PSM) 15% 0.85 [0.61-1.12] 46/142 59/142 Mulhem -32% 1.32 [1.07-1.62] 157/794 359/2,425 Gadhiya -1% 1.01 [0.48-1.91] 19/55 36/226 Elhadi (ICU) -12% 1.12 [0.96-1.31] 175/277 106/188 ICU patients Suna 21% 0.79 [0.44-1.41] 17/153 24/170 Pourhoseingholi 13% 0.87 [0.63-1.19] 54/199 285/2,269 Li (ICU) -11% 1.11 [0.79-1.54] 7/8 19/24 ICU patients Vishnuram 54% 0.46 [0.24-0.86] 164/8,634 10/241 Özgünay (ICU) 9% 0.91 [0.63-1.30] 17/32 75/128 ICU patients Zheng (PSM) -157% 2.57 [0.39-16.8] 12/70 7/327 Simsek 44% 0.56 [0.23-1.35] 6/58 15/81 Shousha 94% 0.06 [0.01-0.37] 22/340 31/207 Tehrani (RCT) 87% 0.13 [0.01-2.25] 0/18 4/26 Majidi (DB RCT) 14% 0.86 [0.74-1.01] 26/31 67/69 ICU patients Baguma -48% 1.48 [0.41-4.70] 385 (n) 96 (n) Gavrielatou (ICU) 58% 0.42 [0.12-1.48] 2/10 49/103 ICU patients Salehi (ICU) 10% 0.90 [0.65-1.25] 22/40 52/85 ICU patients Hess (IPW) 20% 0.80 [0.40-1.60] 10/25 37/75 Tau​2 = 0.17, I​2 = 84.7%, p = 0.0038 Late treatment 26% 0.74 [0.61-0.91] 871/11,706 1,392/7,283 26% improvement All studies 25% 0.75 [0.61-0.91] 872/11,754 1,392/7,333 25% improvement 27 vitamin C COVID-19 mortality results c19vitaminc.com May 2022 Tau​2 = 0.17, I​2 = 84.2%, p = 0.0043 1 CT: study uses combined treatment Favors vitamin C Favors control
Figure 5. Random effects meta-analysis for mortality results.
0 0.25 0.5 0.75 1 1.25 1.5 1.75 2+ Kumari (RCT) 20% 0.80 [0.40-1.59] 12/75 15/75 Improvement, RR [CI] Treatment Control JamaliMo.. (RCT) -25% 1.25 [0.37-4.21] 5/30 4/30 Özgünay (ICU) -1% 1.01 [0.79-1.29] 23/32 91/128 ICU patients Hess (IPW) 40% 0.60 [0.28-1.00] 18/25 54/75 Tau​2 = 0.07, I​2 = 61.4%, p = 0.27 Late treatment 18% 0.82 [0.57-1.16] 58/162 164/308 18% improvement All studies 18% 0.82 [0.57-1.16] 58/162 164/308 18% improvement 4 vitamin C COVID-19 mechanical ventilation results c19vitaminc.com May 2022 Tau​2 = 0.07, I​2 = 61.4%, p = 0.27 Favors vitamin C Favors control
Figure 6. Random effects meta-analysis for ventilation.
0 0.25 0.5 0.75 1 1.25 1.5 1.75 2+ Darban (RCT) 6% 0.94 [0.84-1.06] 10 (n) 10 (n) ICU patients CT​1 Improvement, RR [CI] Treatment Control Hakamifard (RCT) 46% 0.54 [0.14-2.08] 3/38 5/34 CT​1 Suna -2% 1.02 [0.46-2.24] 11/153 12/170 Simsek 10% 0.90 [0.55-1.46] 18/58 28/81 Hess (IPW) 27% 0.73 [0.41-1.04] 22/25 63/75 Tau​2 = 0.01, I​2 = 36.8%, p = 0.048 Late treatment 15% 0.85 [0.72-1.00] 54/284 108/370 15% improvement All studies 15% 0.85 [0.72-1.00] 54/284 108/370 15% improvement 5 vitamin C COVID-19 ICU results c19vitaminc.com May 2022 Tau​2 = 0.01, I​2 = 36.8%, p = 0.048 1 CT: study uses combined treatment Favors vitamin C Favors control
Figure 7. Random effects meta-analysis for ICU admission.
0 0.25 0.5 0.75 1 1.25 1.5 1.75 2+ Thomas (RCT) 31% 0.69 [0.12-3.98] hosp. 2/48 3/50 Improvement, RR [CI] Treatment Control Tau​2 = 0.00, I​2 = 0.0%, p = 0.7 Early treatment 31% 0.69 [0.12-3.98] 2/48 3/50 31% improvement Kumari (RCT) 24% 0.76 [0.66-0.87] hosp. time 75 (n) 75 (n) Improvement, RR [CI] Treatment Control JamaliMo.. (RCT) -31% 1.31 [1.03-1.66] hosp. time 30 (n) 30 (n) Hamidi-A.. (RCT) 38% 0.62 [0.45-0.86] hosp. time 40 (n) 40 (n) CT​1 Hakamifard (RCT) 1% 0.99 [0.91-1.07] hosp. time 38 (n) 34 (n) CT​1 Tehrani (RCT) 18% 0.82 [0.60-1.13] hosp. time 18 (n) 26 (n) Tau​2 = 0.04, I​2 = 84.0%, p = 0.24 Late treatment 12% 0.88 [0.72-1.09] 0/201 0/205 12% improvement Abdulateef 19% 0.81 [0.37-1.78] hosp. 8/132 22/295 Improvement, RR [CI] Treatment Control Nimer 25% 0.75 [0.54-1.04] hosp. 52/651 167/1,497 Tau​2 = 0.00, I​2 = 0.0%, p = 0.053 Prophylaxis 24% 0.76 [0.58-1.00] 60/783 189/1,792 24% improvement All studies 14% 0.86 [0.73-1.02] 62/1,032 192/2,047 14% improvement 8 vitamin C COVID-19 hospitalization results c19vitaminc.com May 2022 Tau​2 = 0.03, I​2 = 74.1%, p = 0.091 1 CT: study uses combined treatment Favors vitamin C Favors control
Figure 8. Random effects meta-analysis for hospitalization.
0 0.25 0.5 0.75 1 1.25 1.5 1.75 2+ Zhao (PSM) 72% 0.28 [0.08-0.93] 4/55 12/55 Improvement, RR [CI] Treatment Control Tau​2 = 0.00, I​2 = 0.0%, p = 0.019 Early treatment 72% 0.28 [0.08-0.93] 4/55 12/55 72% improvement Darban (RCT) 33% 0.67 [0.14-3.17] 2/10 3/10 ICU patients CT​1 Improvement, RR [CI] Treatment Control Tan 73% 0.27 [0.09-0.61] 7/46 41/115 CT​1 Coppock (RCT) 5% 0.95 [0.16-7.84] 4/44 2/22 Tau​2 = 0.13, I​2 = 23.9%, p = 0.028 Late treatment 59% 0.41 [0.19-0.91] 13/100 46/147 59% improvement All studies 66% 0.34 [0.20-0.58] 17/155 58/202 66% improvement 4 vitamin C COVID-19 progression results c19vitaminc.com May 2022 Tau​2 = 0.00, I​2 = 0.0%, p < 0.0001 1 CT: study uses combined treatment Favors vitamin C Favors control
Figure 9. Random effects meta-analysis for progression.
0 0.25 0.5 0.75 1 1.25 1.5 1.75 2+ Thomas (RCT) 18% 0.82 [0.63-1.07] recov. time 48 (n) 50 (n) Improvement, RR [CI] Treatment Control Ried (RCT) 31% 0.69 [0.54-0.89] no recov. 69/162 46/75 Tau​2 = 0.00, I​2 = 0.0%, p = 0.0024 Early treatment 25% 0.75 [0.63-0.90] 69/210 46/125 25% improvement Kumari (RCT) 26% 0.74 [0.64-0.86] recov. time 75 (n) 75 (n) Improvement, RR [CI] Treatment Control Yang (RCT) 15% 0.85 [0.68-1.06] recov. time 10 (n) 10 (n) LD​1 Coppock (RCT) 22% 0.78 [0.61-0.98] no disch. 31/44 20/22 Tau​2 = 0.00, I​2 = 0.0%, p < 0.0001 Late treatment 23% 0.77 [0.69-0.86] 31/129 20/107 23% improvement All studies 23% 0.77 [0.70-0.84] 100/339 66/232 23% improvement 5 vitamin C COVID-19 recovery results c19vitaminc.com May 2022 Tau​2 = 0.00, I​2 = 0.0%, p < 0.0001 1 LD: comparison with low dose treatment Favors vitamin C Favors control
Figure 10. Random effects meta-analysis for recovery.
0 0.25 0.5 0.75 1 1.25 1.5 1.75 2+ Behera 18% 0.82 [0.45-1.57] cases case control Improvement, RR [CI] Treatment Control Louca 0% 1.00 [0.97-1.04] cases Holt -3% 1.03 [0.77-1.39] cases 49/1,580 397/13,647 Mohseni -44% 1.44 [1.22-1.71] cases 34/43 307/560 Tau​2 = 0.04, I​2 = 83.4%, p = 0.52 Prophylaxis -8% 1.08 [0.86-1.35] 83/1,623 704/14,207 -8% improvement All studies -8% 1.08 [0.86-1.35] 83/1,623 704/14,207 -8% improvement 4 vitamin C COVID-19 case results c19vitaminc.com May 2022 Tau​2 = 0.04, I​2 = 83.4%, p = 0.52 Favors vitamin C Favors control
Figure 11. Random effects meta-analysis for cases.
0 0.25 0.5 0.75 1 1.25 1.5