Summary of COVID-19 favipiravir studies

50 patient favipiravir late treatment RCT: 89% greater improvement (p=0.005) and 92% improved viral clearance (p=0.0008).
RCT hospitalized patients in Bangladesh, showing faster recovery and viral clearance with favipiravir treatment.
May 2022, Clinical Infection in Practice, https://www.sciencedirect.com/science/article/pii/S2590170222000139, https://c19p.org/rahman2

2. Sirijatuphat et al., Early Treatment of Favipiravir in COVID-19 Patients Without Pneumonia: A Multicentre, Open-Labelled, Randomized Control Study

93 patient favipiravir early treatment RCT: 64% faster improvement (p=0.0005), 43% lower progression (p=0.25), and 4% worse viral clearance (p=0.87).
RCT 93 patients in Thailand showing significantly faster clinical improvement with favipiravir treatment. 1800mg favipiravir bid day 1, 800mg bid 5-14 days until PCR-.
Jun 2022, medRxiv, https://www.medrxiv.org/content/10.1101/2022.06.06.22275902v1, https://c19p.org/sirijatuphat2

3. Pushkar et al., Study of Favipiravir Compared to Standard of Care in Hospitalized Patients With COVID-19

200 patient favipiravir late treatment RCT: 14% improved recovery (p=0.06), 70% higher hospital discharge (p=0.0001), 33% lower pneumonia (p=0.007), and 90% improved viral clearance (p<0.0001).
RCT 200 patients showing improvements in clinical recovery and viral clearance with favipiravir. There is no paper available but results are posted in clinicaltrials.gov.
Nov 2020, NCT04542694, https://clinicaltrials.gov/ct2/show/results/NCT04542694?view=results, https://c19p.org/pushkar

4. Shinkai et al., Efficacy and Safety of Favipiravir in Moderate COVID-19 Pneumonia Patients without Oxygen Therapy: A Randomized, Phase III Clinical Trial

156 patient favipiravir late treatment RCT: 37% faster recovery (p=0.01).
RCT 156 patients in Japan, 107 treated with favipiravir, showing significant improvement in a composite outcome defined as the time to improvement in temperature, SpO2, CT findings, and recovery to PCR-.
Aug 2021, Infectious Diseases and Therapy, https://link.springer.com/article/10.1007/s40121-021-00517-4, https://c19p.org/shinkai

5. Udwadia et al., Efficacy and Safety of Favipiravir, an Oral RNA-Dependent RNA Polymerase Inhibitor, in Mild-to-Moderate COVID-19: A Randomized, Comparative, Open-Label, Multicenter, Phase 3 Clinical Trial

148 patient favipiravir early treatment RCT: 29% faster recovery (p=0.07) and 27% faster viral clearance (p=0.1).
RCT with 75 favipiravir patients and 75 control patients showing improved recovery with treatment.
Nov 2020, Int. J. Infectious Diseases, https://www.sciencedirect.com/science/article/pii/S120197122032453X, https://c19p.org/udwadia

6. Cai et al., Experimental Treatment with Favipiravir for COVID-19: An Open-Label Control Study

80 patient favipiravir late treatment study: 69% lower pneumonia (p=0.04) and 71% improved viral clearance (p=0.03).
Comparison of 35 FPV patients and 35 LPV/RTV patients, showing significant improvements in chest CT and faster viral clearance with FPV.
Mar 2020, Engineering, https://www.sciencedirect.com/science/article/pii/S2095809920300631, https://c19p.org/cai

7. Golan et al., Favipiravir in patients with early mild-to-moderate COVID-19: a randomized controlled trial

1,187 patient favipiravir early treatment RCT: 2% lower progression (p=1), 4% improved recovery (p=0.79), and 14% faster viral clearance (p<0.0001).
RCT low-risk (1 death in the control arm) patients in the USA, showing no significant differences with favipiravir. A majority of trial outcomes were modified after completion: [clinicaltrials.gov]. 44% of patients had no detectable viral load at baseline in the viral shedding sub-study. The primary outcome required 4 days of sustained clinical recovery and occurred after a median of 7 days, suggesting there was limited room for improvement in the population studied. The percentages for viral clearance at day 10 do not match any number of the reported group sizes. Authors write "of the six RCTs conducted", however there has been at least 24 other RCTs at the time of publication [c19favipiravir.com]. 1800mg bid day 1, 800mg bid days 2-10.
Sep 2022, Clinical Infectious Diseases, https://academic.oup.com/cid/advance-article/doi/10.1093/cid/ciac712/6692456, https://c19p.org/golan

8. Kulzhanova et al., Clinical efficacy of the antiviral drug favipiravir in the complex treatment of patients with COVID-19 coronavirus infection

80 patient favipiravir late treatment study: 88% greater improvement (p<0.0001) and 50% improved viral clearance (p=0.18).
Retrospective 40 favipiravir patients in Kazakhstan and 40 controls, showing faster recovery and viral clearance with treatment.
Aug 2021, , https://newjournal.ssmu.kz/upload/iblock/026/6_15_4_23_2021.pdf, https://c19p.org/kulzhanova

9. Holubar et al., Favipiravir for treatment of outpatients with asymptomatic or uncomplicated COVID-19: a double-blind randomized, placebo-controlled, phase 2 trial

149 patient favipiravir early treatment RCT: 89% lower hospitalization (p=0.06), 30% lower progression (p=0.56), 19% worse recovery (p=0.43), and 32% worse viral clearance (p=0.24).
Small RCT 116 mITT patients in the USA, 59 treated with favipiravir, showing no significant differences with treatment.
Nov 2021, Clinical Infectious Diseases, https://academic.oup.com/cid/advance-article/doi/10.1093/cid/ciac312/6572081, https://c19p.org/holubar

10. Hartantri et al., Clinical and treatment factors associated with the mortality of COVID-19 patients admitted to a referral hospital in Indonesia

favipiravir late treatment study: 76% lower mortality (p=0.0005).
Retrospective 689 hospitalized patients in Indonesia, showing lower mortality with favipiravir treatment.
Feb 2023, The Lancet Regional Health - Southeast Asia, https://www.sciencedirect.com/science/article/pii/S2772368223000276, https://c19p.org/hartantri

11. Usanma Koban et al., The factors affecting the prolonged PCR positivity in COVID-19 patients

126 patient favipiravir early treatment study: 86% improved viral clearance (p=0.03).
Retrospective 126 patients in Turkey, showing lower risk of PCR+ at day 14 with favipiravir treatment.
Jun 2022, Bratislava Medical J., http://www.elis.sk/index.php?page=shop.product_details&flypage=flypage.tpl&product_id=7706&category_id=179&option=com_virtuemart, https://c19p.org/usanmakoban

12. Sawanpanyalert et al., Assessment of outcomes following implementation of antiviral treatment guidelines for COVID-19 during the first wave in Thailand

favipiravir early treatment study: 68% lower progression (p=0.003).
Retrospective 744 hospitalized patients in Thailand, showing lower risk of a poor outcome for favipiravir treatment within 4 days of symptom onset. Early treatment with CQ/HCQ and lopinavir/ritonavir or darunavir/ritonavir also showed lower risk, but without statistical significance. Sample sizes for the number of patients treated within 4 days of symptom onset are not provided.
Sep 2021, Southeast Asian J. Tropical Medicine and Public Health, https://journal.seameotropmednetwork.org/index.php/jtropmed/article/view/490, https://c19p.org/sawanpanyalerta

13. Shah et al., Favipiravir in patients hospitalised with COVID-19 (PIONEER trial): a multicentre, open-label, phase 3, randomised controlled trial of early intervention versus standard care

499 patient favipiravir late treatment RCT: 26% lower mortality (p=0.24), 24% lower ventilation (p=0.21), and 6% improved recovery (p=0.53).
PIONEER very late treatment RCT showing lower mortality and mechanical ventilation with favipiravir, without statistical significance. The conclusion "favipiravir is not efficacious in treating hospitalised adult patients with COVID-19" is incorrect. Authors show 26% and 24% lower mortality and mechanical ventilation. While these results are not statistically significant, they predict efficacy, and cannot be used to rule out efficacy. Favipiravir 1,800mg bid day 1, 800mg bid days 2-10.
Sep 2022, The Lancet Respiratory Medicine, https://www.sciencedirect.com/science/article/pii/S221326002200412X, https://c19p.org/shah5

14. Qadir et al., Efficacy of Favipiravir in the Treatment of Mild to Moderate COVID-19 Patients in Erbil: A Controlled Clinical Trial

250 patient favipiravir early treatment study: 97% lower mortality (p<0.0001), 60% lower hospitalization (p=0.001), and 97% improved recovery (p<0.0001).
Prospective study with 125 favipiravir patients and 125 patients declining favipiravir treatment, showing lower mortality and improved recovery with treatment. All patients received vitamin C, D, and zinc. Favipiravir 3200mg day 1, followed by 600mg bid days 2-10.
May 2022, Int. J. Applied Sciences: Current and Future Research Trends, https://ijascfrtjournal.isrra.org/index.php/Applied_Sciences_Journal/article/view/1235, https://c19p.org/qadir

15. Hobbs et al., Favipiravir for COVID-19 in adults in the community in PRINCIPLE, an open-label, randomised, controlled, adaptive platform trial of short- and longer-term outcomes

3,622 patient favipiravir late treatment RCT: 86% lower mortality (p=0.11), 1% lower combined mortality/hospitalization (p=0.51), and 17% improved recovery (p=0.003).
RCT 3,622 (concurrent and eligible) COVID-19 outpatients in the UK showing significantly faster recovery with favipiravir, and significantly greater full recovery at 3, 6, and 12 months. Authors note: "From 16 Dec 2021, a minority of extremely clinically vulnerable patients could also access antiviral treatment or a monoclonal antibody infusion". However, there is no information on treatments provided or procedures for determining eligibility. This change invalidates hospitalization/death data after 16 Dec 2021. Hospitalization/death events occured in a small minority of patients and are expected to be strongly biased towards the extremely clinically vulnerable patients. Patients randomized to usual care are more likely to obtain alternative treatment. During the trial extension period sotrovimab was the most common treatment, with paxlovid and molnupiravir also being used [england.nhs.uk]. Sotrovimab showed very high efficacy during this period [Behzad, De Vito]. It..
Aug 2024, J. Infection, https://www.sciencedirect.com/science/article/pii/S0163445324001828, https://c19p.org/hobbs

16. Zhao et al., Favipiravir in the treatment of patients with SARS-CoV-2 RNA recurrent positive after discharge: a multicenter, open-label, randomized trial

55 patient favipiravir late treatment RCT: 59% improved viral clearance (p=0.06).
RCT with 55 patients (36 favipiravir, 19 control) who were PCR+ after recovery, showing improved viral clearance with treatment.
Apr 2021, Int. Immunopharmacology, https://www.sciencedirect.com/science/article/pii/S1567576921003386, https://c19p.org/zhao2

17. Atipornwanich et al., Various Combinations of Favipiravir, Lopinavir-Ritonavir, Darunavir-Ritonavir, High-Dose Oseltamivir, and Hydroxychloroquine for the Treatment of COVID-19: A Randomized Controlled Trial (FIGHT-COVID-19 Study)

200 patient favipiravir late treatment RCT: 23% lower mortality (p=0.66), 60% lower progression (p=0.009), and 9% faster viral clearance (p=0.43).
RCT 200 moderate/severe patients in Thailand, showing significantly lower progression with favipiravir vs. oseltamivir. NCT04303299.
Oct 2021, SSRN Electronic J., https://papers.ssrn.com/sol3/papers.cfm?abstract_id=3936499, https://c19p.org/atipornwanicha

18. Delen et al., Effects of Hydroxychloroquine Plus Favipiravir Treatment on the Clinical Course and Biomarkers in Hospitalized COVID-19 Patients with Pneumonia

69 patient favipiravir late treatment study: 88% improved recovery (p=0.02), 2% longer hospitalization (p=0.74), and 3% lower hospital discharge (p=1).
Retrospective 69 COVID-19 patients in Turkey, showing improved fever recovery with the addition of favipiravir to HCQ, but no significant difference in discharge, ICU admission, or hospitalization time.
Dec 2022, Acta Clinica Croatica, https://hrcak.srce.hr/clanak/428402, https://c19p.org/delen

19. Tawfik et al., Effectiveness of Early Favipiravir Therapy in Hospitalised COVID-19 Patients

165 patient favipiravir late treatment study: 96% lower mortality (p<0.0001), 21% lower ICU admission (p=0.45), and 16% shorter hospitalization (p<0.0001).
Retrospective 103 hospitalized patients in Saudi Arabia, showing lower mortality with favipiravir in unadjusted results, and greater efficacy for treatment within 3 days of admission.
Jun 2022, Advances in Virology, https://www.hindawi.com/journals/av/2022/9240941/, https://c19p.org/tawfik

20. Tehrani et al., Efficacy of Favipiravir in the Treatment of Moderate COVID-19 Patients: A Randomized, Open-label, Controlled Clinical Trial

78 patient favipiravir late treatment RCT: 34% lower hospitalization (p=0.24).
RCT 78 patients in Iran, showing improved recovery with favipiravir treatment.
Jun 2022, Mediterranean J. Infection Microbes and Antimicrobials, https://mjima.org/pdf.php?&id=340, https://c19p.org/tehrani4

21. Shinada et al., Longitudinal Analysis of Neutralizing Potency against SARS-CoV-2 in the Recovered Patients after Treatment with or without Favipiravir

34 patient favipiravir late treatment study: 7% shorter hospitalization (p=0.84) and 55% faster viral clearance (p=0.04).
Retrospective 17 COVID+ patients treated with favipiravir and 17 matched controls in Japan, showing faster viral clearance with treatment. Favipiravir 3600mg day one, 1600mg per day for up to 14 days.
Mar 2022, Viruses, https://www.mdpi.com/1999-4915/14/4/670, https://c19p.org/shinada

22. Alattar et al., Favipiravir for the Treatment of Coronavirus Disease 2019 Pneumonia; a Propensity Score-matched Cohort Study

774 patient favipiravir early treatment PSM study: 33% lower mortality (p=0.5), 2% worse recovery (p=0.73), and 44% improved viral clearance (p<0.0001).
PSM retrospective with 1,493 patients, showing significantly improved viral clearance with favipiravir. There were no significant differences in clinical improvement or mortality. Mortality was lower (2.1% vs 3.1%), without statistical significance with the small number of events.
Nov 2021, J. Infection and Public Health, https://www.sciencedirect.com/science/article/pii/S187603412200212X, https://c19p.org/alattar

23. Arfijanto et al., Duration of SARS-CoV-2 RNA Shedding Is Significantly Influenced by Disease Severity, Bilateral Pulmonary Infiltrates, Antibiotic Treatment, and Diabetic Status: Consideration for Isolation Period

162 patient favipiravir late treatment study: 51% improved viral clearance (p=0.02).
Retrospective 162 hospitalized COVID-19 patients in Indonesia, showing lower incidence of delayed viral clearance with favipiravir treatment in unadjusted results.
May 2023, Pathophysiology, https://www.mdpi.com/1873-149X/30/2/16, https://c19p.org/arfijanto

24. Hassaniazad et al., Efficacy and safety of favipiravir plus interferon-beta versus lopinavir/ritonavir plus interferon-beta in moderately ill patients with COVID-19: A randomized clinical trial

63 patient favipiravir late treatment RCT: 68% lower mortality (p=0.15), 35% lower ICU admission (p=0.51), 25% shorter hospitalization (p=0.14), and 18% improved viral clearance (p=0.24).
RCT comparing favipiravir and lopinavir/ritonavir, showing no significant differences. All patients received interferon-beta. Favipiravir 1600mg bid for the first day and 600mg bid for the following 4 days.
Mar 2022, J. Medical Virology, https://onlinelibrary.wiley.com/doi/10.1002/jmv.27724, https://c19p.org/hassaniazad2

25. Yulia et al., Evaluation of Antibacterial and Antiviral Drug Effectiveness in COVID-19 Therapy: A Data-Driven Retrospective Approach

432 patient favipiravir late treatment study: 85% lower mortality (p=0.05).
Retrospective hospitalized patients in Indonesia, showing lower mortality and shorter hospitalization with favipiravir.
Mar 2022, Pathophysiology, https://www.mdpi.com/1873-149X/29/1/9, https://c19p.org/yulia

26. Damayanti et al., The Effectiveness and Safety of Favipiravir in COVID-19 Hospitalized Patients in Bali, Indonesia

192 patient favipiravir late treatment study: 54% improved recovery (p=0.03).
Retrospective 192 hospitalized patients in Indonesia, 96 patients treated with favipiravir, showing improved recovery with treatment. Only the abstract is currently available.
Oct 2021, Kesmas: National Public Health J., https://journal.fkm.ui.ac.id/kesmas/article/view/5433, https://c19p.org/damayanti

27. Alamer et al., Effectiveness and safety of favipiravir compared to supportive care in moderately to critically ill COVID-19 patients: a retrospective study with propensity score matching sensitivity analysis

456 patient favipiravir late treatment study: 56% higher mortality (p=0.26), 90% lower ventilation (p<0.0001), and 49% higher hospital discharge (p<0.0001).
Retrospective 234 favipiravir and 223 control patients in Saudi Arabia, showing shorter time to discharge and lower progression to ventilation, but no significant difference in mortality.
May 2021, Current Medical Research and Opinion, https://www.tandfonline.com/doi/full/10.1080/03007995.2021.1920900, https://c19p.org/alamer

28. Tabarsi et al., Favipiravir Effects on the Control of Clinical Symptoms of Hospitalized COVID-19 Cases: An Experience with Iranian Formulated Dosage Form

62 patient favipiravir late treatment RCT: 41% lower ICU admission (p=0.36), 6% improved recovery (p=0.76), and 25% shorter hospitalization (p=0.03).
Small 62 patient late stage RCT in Iran comparing favipiravir and lopinavir/ritonavir, showing significant improvement in fever, cough, and dyspnea with favipiravir on day 5. There was no significant difference in mortality, ICU admission, or chest CT improvement. IRCT20151227025726N14.
Sep 2021, Iranian J. Pharmaceutical Research, http://ijpr.sbmu.ac.ir/article_1101552.html, https://c19p.org/tabarsi

29. Behboodikhah et al., Evaluation of the Costs and Outcomes of COVID-19 Therapeutic Regimens in Hospitalized Patients in Shiraz

2,174 patient favipiravir late treatment study: 68% lower mortality (p=0.2).
Retrospective 2,174 hospitalized patients showing significantly shorter length of stay with favipiravir treatment.
Sep 2022, Iranian J. Science and Technology, Transactions A: Science, https://link.springer.com/10.1007/s40995-022-01351-0, https://c19p.org/behboodikhah

30. Chen et al., Favipiravir Versus Arbidol for Clinical Recovery Rate in Moderate and Severe Adult COVID-19 Patients: A Prospective, Multicenter, Open-Label, Randomized Controlled Clinical Trial

236 patient favipiravir late treatment RCT: 74% lower progression (p=0.37), 20% lower need for oxygen therapy (p=0.42), and 20% improved recovery (p=0.15).
Very late stage (9 days from symptom onset) RCT with 116 favipiravir patients and 120 arbidol patients in China, showing no significant difference in clinical recovery (relief of fever and cough, respiratory frequency ≤24 times/min, and oxygen saturation ≥98%), however the time to resolution of fever and cough was significantly lower with favipiravir. ChiCTR2000030254.
Sep 2021, Frontiers in Pharmacology, https://www.frontiersin.org/articles/10.3389/fphar.2021.683296/full, https://c19p.org/chen4

31. Kurniyanto et al., Factors Associated with Death and ICU Referral among COVID-19 Patients Hospitalized in the Secondary Referral Academic Hospital in East Jakarta, Indonesia

477 patient favipiravir late treatment study: 48% lower mortality (p=0.21).
Retrospective 477 hospitalized patients in Indonesia, showing lower mortality with favipiravir in unadjusted results, not reaching statistical significance.
Feb 2022, J. Clinical Virology Plus, https://www.sciencedirect.com/science/article/pii/S2667038022000084, https://c19p.org/kurniyanto

32. Alotaibi et al., Effectiveness and Safety of Favipiravir Compared to Hydroxychloroquine for Management of Covid-19: A Retrospective Study

437 patient favipiravir late treatment study: 57% lower mortality (p=0.05).
Retrospective hospitalized patients in Saudi Arabia, showing lower mortality with favipiravir compared to HCQ, not quite reaching statistical significance. Authors do not indicate the factors behind which therapy was chosen. May be subject to significant confounding by indication and confounding by time.
Sep 2021, Int. J. General Medicine, https://www.dovepress.com/getfile.php?fileID=73585, https://c19p.org/alotaibia

33. Cilli et al., Characteristics and outcomes of COVID-19 patients with IPF: A multi-center retrospective study

46 patient favipiravir late treatment study: 38% lower mortality (p=0.51).
Retrospective 46 idiopathic pulmonary fibrosis patients with COVID-19 in Turkey, showing lower mortality with favipiravir in unadjusted results, without statistical significance.
Mar 2022, Respiratory Medicine and Research, https://www.sciencedirect.com/science/article/pii/S2590041222000174?via%3Dihub, https://c19p.org/cilli

34. Haji Aghajani et al., Decreased In-Hospital Mortality Associated with Aspirin Administration in Hospitalized Patients Due to Severe COVID-19

991 patient favipiravir late treatment study: 26% lower mortality (p=0.28).
Retrospective 991 hospitalized patients in Iran focusing on aspirin use but also showing results for HCQ, remdesivir, and favipiravir.
Apr 2021, J. Medical Virology, https://europepmc.org/article/med/33913549, https://c19p.org/hajiaghajania

35. Tsuzuki et al., Effectiveness of Favipiravir on Nonsevere, Early-Stage COVID-19 in Japan: A Large Observational Study Using the COVID-19 Registry Japan

7,654 patient favipiravir early treatment study: 13% lower mortality (p=0.59), 2% higher ventilation (p=0.93), and 18% lower progression (p=0.1).
Retrospective database analysis of 7,654 hospitalized patients in Japan, showing no significant differences with favipiravir treatment. NCGM-G-003494-0.
Mar 2022, Infectious Diseases and Therapy, https://link.springer.com/article/10.1007/s40121-022-00617-9/fulltext.html, https://c19p.org/tsuzuki2

36. Shamsi et al., Survival and Mortality in Hospitalized Children with COVID-19: A Referral Center Experience in Yazd, Iran

183 patient favipiravir late treatment study: 96% lower mortality (p=0.14).
Retrospective 183 hospitalized pediatric COVID-19 patients in Iran, showing no significant difference in mortality with in unadjusted results.
Jul 2023, Canadian J. Infectious Diseases and Medical Microbiology, https://www.hindawi.com/journals/cjidmm/2023/5205188/, https://c19p.org/shamsi

37. Lokanuwatsatien et al., Prevalence and associating factors of long COVID in pediatric patients during the Delta and the Omicron variants

802 patient favipiravir early treatment study: 14% lower PASC (p=0.34).
Prospective analysis of 802 COVID-19 pediatric patients in Thailand, showing no significant difference in long COVID with favipiravir treatment in unadjusted results.
May 2023, Frontiers in Pediatrics, https://www.frontiersin.org/articles/10.3389/fped.2023.1127582/full, https://c19p.org/lokanuwatsatien

38. Alosaimi et al., Analyzing the Difference in the Length of Stay (LOS) in Moderate to Severe COVID-19 Patients Receiving Hydroxychloroquine or Favipiravir

74 patient favipiravir late treatment PSM study: 80% lower mortality (p=0.49), 75% longer hospitalization (p=0.63), and 40% lower hospital discharge (p=0.74).
Retrospective 200 hospitalized COVID-19 patients in Saudi Arabia, showing no significant difference in outcomes between HCQ and favipiravir.
Nov 2022, Pharmaceuticals, https://www.mdpi.com/1424-8247/15/12/1456, https://c19p.org/alosaimia

39. Uyaroğlu et al., Comparison of Favipiravir to Hydroxychloroquine Plus Azithromycin in the Treatment of Patients with Non-critical COVID-19: A Single-center, Retrospective, Propensity Score-matched Study

84 patient favipiravir late treatment PSM study: 67% lower mortality (p=1), 200% higher ICU admission (p=1), and 11% longer hospitalization (p=0.9).
PSM retrospective 260 late stage hospitalized COVID-19 pneumonia patients in Turkey, showing no significant difference between favipiravir and HCQ.
Mar 2022, Acta Medica, https://actamedica.org/index.php/actamedica/article/view/719, https://c19p.org/uyaroglua

40. Acar Sevinc et al., Favipiravir Experience in COVID-19 Patients at a Tertiary Center Intensive Care Unit

100 patient favipiravir ICU study: 16% lower mortality (p=0.38) and 10% lower ventilation (p=0.75).
Retrospective 100 ICU patients in Turkey, showing improved survival with favipiravir vs. lopinavir/ritonavir.
Jun 2022, SiSli Etfal Hastanesi Tip Bulteni / The Medical Bulletin of Sisli Hospital, https://sislietfaltip.org/jvi.aspx?un=SETB-35902&volume=, https://c19p.org/acarsevinc

41. Abdulrahman et al., Favipiravir efficacy and safety for the treatment of severe coronavirus 2019: a retrospective study

1,699 patient favipiravir ICU study: 3% lower mortality (p=0.81).
Retrospective 1,699 ICU patients in Saudi Arabia, 193 treated with favipiravir, showing no significant difference in mortality.
Jun 2022, J. Ayub Medical College Abbottabad, https://jamc.ayubmed.edu.pk/jamc/index.php/jamc/article/view/10305, https://c19p.org/abdulrahman2

42. Khamis et al., Randomized Controlled Open Label Trial on the Use of Favipiravir Combined with Inhaled Interferon beta-1b in Hospitalized Patients with Moderate to Severe COVID-19 Pneumonia

89 patient favipiravir late treatment RCT: 15% lower mortality (p=1), 2% higher ICU admission (p=1), and 10% worse recovery (p=0.82).
Small 89 patient RCT comparing favipiravir and inhaled interferon with HCQ for moderate to severe COVID-19 pneumonia, not finding significant differences. There was no control group.
Nov 2020, Int. J. Infectious Diseases, https://www.sciencedirect.com/science/article/pii/S1201971220323195, https://c19p.org/khamisf

43. Al Mutair et al., Overview of Clinical Outcome and Therapeutic Effectiveness of Favipiravir in Patients with COVID-19 Admitted to Intensive Care Unit, Riyadh, Saudi Arabia

538 patient favipiravir ICU study: 7% lower mortality (p=0.49), 9% higher ARDS (p=0.63), 34% longer ICU admission (p=0.001), and 37% longer hospitalization (p=0.001).
Retrospective 269 favipiravir ICU patients in Saudi Arabia and 269 matched controls receiving different treatments, showing no significant difference.
Feb 2022, J. Infection and Public Health, https://www.sciencedirect.com/science/article/pii/S1876034122000259, https://c19p.org/almutair

44. Al-Muhsen et al., Favipiravir Effectiveness and Safety in Hospitalized Moderate-Severe COVID-19 Patients: Observational Prospective Multicenter Investigation in Saudi Arabia

598 patient favipiravir late treatment study: 263% higher mortality (p=0.04), 41% lower need for oxygen therapy (p<0.0001), and 40% longer hospitalization (p=0.03).
Prospective observational study of 598 hospitalized patients in Saudi Arabia, showing higher risk of mortality and longer hospitalization time with favipiravir.
Mar 2022, Frontiers in Medicine, https://www.frontiersin.org/articles/10.3389/fmed.2022.826247/full, https://c19p.org/almuhsen

45. Ruzhentsova et al., Phase 3 Trial of Coronavir (Favipiravir) in Patients with Mild to Moderate COVID-19

168 patient favipiravir early treatment RCT: 39% faster recovery (p=0.007) and 22% improved viral clearance (p=0.16).
RCT 168 patients, 112 receiving favipiravir and 56 SOC, showing shorter time to clinical improvement and faster viral clearance with favipiravir.
Oct 2020, SSRN, https://papers.ssrn.com/sol3/papers.cfm?abstract_id=3696907, https://c19p.org/ruzhentsova

46. Hafez et al., Antiviral Used among Non-Severe COVID-19 Cases in Relation to Time till Viral Clearance: A Retrospective Cohort Study

1,505 patient favipiravir late treatment study: 3% slower viral clearance (p=0.09).
Retrospective hospitalized patients in the United Arab Emirates, showing no significant difference in viral clearance with different combinations of HCQ, AZ, favipiravir, and lopinavir/ritonavir.
Apr 2022, Antibiotics, https://www.mdpi.com/2079-6382/11/4/498, https://c19p.org/hafeza

47. Sulaiman et al., When Antivirals Backfire: An Evaluation of Favipiravir’s Clinical Outcomes in Critically Ill Patients with COVID-19: A Multicenter Cohort Study

146 patient favipiravir ICU PSM study: 17% higher mortality (p=0.51), 47% longer ventilation (p=0.008), and 50% longer ICU admission (p=0.01).
PSM retrospective 1,218 COVID-19 ICU patients in Saudi Arabia, showing no significant difference in mortality, and longer ICU/MV time with favipiravir treatment.
Jun 2023, J. Infection and Public Health, https://www.sciencedirect.com/science/article/pii/S1876034123002162, https://c19p.org/sulaiman2

48. Saito et al., Predictors of in-hospital mortality in elderly unvaccinated patients during SARS-CoV-2 Alpha variants epidemic

132 patient favipiravir late treatment study: 168% higher mortality (p=0.06).
Retrospective 132 hospitalized COVID-19 patients over age 65 in Japan during the Alpha variant surge, showing higher mortality with favipiravir in unadjusted results, without statistical significance.
Jan 2024, Infection Prevention in Practice, https://www.sciencedirect.com/science/article/pii/S2590088924000052, https://c19p.org/saito2

49. Assiri et al., COVID-19 related treatment and outcomes among COVID-19 ICU patients: A retrospective cohort study

118 patient favipiravir ICU study: 79% higher mortality (p=0.5).
Retrospective 118 ICU patients in Saudi Arabia showing no significant differences in unadjusted results with zinc, vitamin D, and favipiravir treatment.
Aug 2021, J. Infection and Public Health, https://www.sciencedirect.com/science/article/pii/S1876034121002495, https://c19p.org/assiria

50. Alsaraj et al., Consequence of Antivirals Versus Standard Care on Clinical Situation in Patients With COVID-19

104 patient favipiravir late treatment RCT: 87% higher mortality (p=0.26).
RCT 156 COVID-19 patients showing higher mortality with favipiravir and remdesivir overall. Favipiravir and remdesivir were more effective when started earlier, however note that Table 10 compares earlier favipiravir/remdesivir+standard care with standard care at any time, which will exaggerate the benefits/harms of earlier/later treatment. The confidence intervals for the Cox results are unusually narrow suggesting a possible error in calculation.
Jan 2024, Infectious Diseases in Clinical Practice, https://journals.lww.com/10.1097/IPC.0000000000001336, https://c19p.org/alsaraja

51. Solaymani-Dodaran et al., Safety and efficacy of Favipiravir in moderate to severe SARS-CoV-2 pneumonia

373 patient favipiravir late treatment RCT: 19% higher mortality (p=0.54), 53% higher ventilation (p=0.15), and 19% higher ICU admission (p=0.56).
RCT late stage patients (median SpO2 89), 193 treated with favipiravir, 187 with lopinavir/ritonavir, showing no significant differences in mortality, intubation, or ICU admission.
Mar 2021, Int. Immunopharmacology, https://www.sciencedirect.com/science/article/pii/S1567576921001582, https://c19p.org/solaymanidodaran

52. Alshamrani et al., Comprehensive evaluation of six interventions for hospitalized patients with COVID-19: A propensity score matching study

2,539 patient favipiravir late treatment PSM study: 14% higher mortality (p=0.13), 2% higher progression (p=0.83), 19% longer ICU admission (p=0.005), and 29% longer hospitalization (p=0.001).
PSM retrospective 29 hospitals in Saudi Arabia, showing higher mortality with favipiravir treatment, without statistical significance.
Feb 2023, Saudi Pharmaceutical J., https://www.sciencedirect.com/science/article/pii/S1319016423000348, https://c19p.org/alshamrania

53. Babayigit et al., The association of antiviral drugs with COVID-19 morbidity: The retrospective analysis of a nationwide COVID-19 cohort

1,302 patient favipiravir late treatment study: 184% higher ventilation (p=0.01), 181% higher ICU admission (p=0.001), and 100% longer hospitalization (p=0.001).
Retrospective 1,472 hospitalized patients in Turkey, showing a higher ICU admission and ventilation with favipiravir. Results may be subject to confounding by indication.
Aug 2022, Frontiers in Medicine, https://www.frontiersin.org/articles/10.3389/fmed.2022.894126/full, https://c19p.org/babayigit

54. Luvira et al., Clinical antiviral efficacy of favipiravir in early COVID-19 (PLATCOV): an open-label, randomised, controlled, adaptive platform trial

248 patient favipiravir early treatment RCT: 6% worse viral clearance (p=0.42).
High conflict of interest RCT with very low risk patients, high existing immunity, and a post-hoc change to exclude patients more likely to benefit. There was no significant difference in viral clearance with favipiravir among patients with high viral load at baseline. Patients in both arms had very short viral clearance half-life times. With rapid viral clearance and very low risk patients, infection is less likely to spread to other tissues. Systemic treatment is less applicable, and has less time to reach therapeutic concentrations before self-recovery. Treatment administered directly to the respiratory tract, e.g. as in [Yildiz Pekoz], may be more effective for COVID-19 in general, and extend applicability to fast-resolving cases with infection primarily localized to the respiratory tract. Authors note that "all-cause hospitalisation for clinical deterioration (until day 28) was a secondary endpoint", but do not provide the result. For more discussion of the post-hoc..
Apr 2023, BMC Infectious Diseases, https://bmcinfectdis.biomedcentral.com/articles/10.1186/s12879-023-08835-3, https://c19p.org/luvira

55. Bruminhent et al., Clinical Course and Outcomes among COVID-19 Patients at the Hospitel in Bangkok: A Retrospective Study

favipiravir early treatment study: 227% higher progression (p=0.005).
Retrospective 514 patients in Thailand, showing higher risk of progression with favipiravir treatment.
Sep 2022, Tropical Medicine and Infectious Disease, https://www.mdpi.com/2414-6366/7/9/238, https://c19p.org/bruminhent

56. Adhikari et al., Efficacy of Favipiravir in treatment of mild & moderate COVID-19 infection in Nepal: a multi-center, randomized, open-labelled, phase III clinical trial

70 patient favipiravir early treatment RCT: 40% worse improvement (p=0.57).
Preliminary report for an RCT in Nepal with 38 favipiravir patients and 32 control patients, showing no significant differences. There were no serious side effects.
Feb 2022, Int. J. Infectious Diseases, https://www.ijidonline.com/article/S1201-9712(21)01001-8/fulltext, https://c19p.org/adhikari

57. Almoosa et al., Favipiravir versus Standard of Care in Patients with Severe COVID-19 Infections: A Retrospective Comparative Study

226 patient favipiravir late treatment study: 42% higher mortality (p=0.1), 90% higher ICU admission (p=0.02), and 11% slower recovery (p=0.17).
Retrospective 226 COVID-19 pneumonia patients, 110 treated with favipiravir, showing higher mortality (p=0.1) and ICU admission (p=0.02) with treatment in multivariate analysis.
Aug 2021, J. Infection and Public Health, https://www.sciencedirect.com/science/article/pii/S1876034121002410, https://c19p.org/almoosa

58. AlQahtani et al., Randomized controlled trial of favipiravir, hydroxychloroquine, and standard care in patients with mild/moderate COVID-19 disease

106 patient favipiravir late treatment RCT: 76% lower ICU admission (p=0.2), 42% worse recovery (p=0.51), and 43% improved viral clearance (p=0.21).
RCT with 54 favipiravir, 51 HCQ, and 52 SOC hospitalized patients in Bahrain, showing no significant differences. Viral clearance improved with both treatments, but did not reach statistical significance with the small sample size.
Mar 2022, Scientific Reports, https://www.nature.com/articles/s41598-022-08794-w, https://c19p.org/alqahtani2a

59. Vaezi et al., Favipiravir in the Treatment of Outpatient COVID-19: A Multicenter, Randomized, Triple-Blind, Placebo-Controlled Clinical Trial

77 patient favipiravir early treatment RCT: 105% higher hospitalization (p=0.43).
RCT 77 outpatients in Iran, showing increased hospitalization with treatment, without statistical significance. Favipiravir 1600mg daily for five days. 21% of favipiravir patients did not complete treatment.
Jan 2023, Advances in Respiratory Medicine, https://www.mdpi.com/2543-6031/91/1/4, https://c19p.org/vaezi

60. Shenoy et al., Favipiravir In Adults with Moderate to Severe COVID-19: A Phase 3 Multicentre, Randomized, Double-Blind, Placebo-Controlled Trial

353 patient favipiravir late treatment RCT: 29% higher mortality (p=0.54), 33% higher ventilation (p=0.54), 2% higher ICU admission (p=0.54), and 1% slower recovery (p=0.94).
Late stage RCT with 353 hospitalized patients, showing no significant differences with favipiravir treatment overall, however a trend towards benefit was seen within patients treated relatively early, including a statistically significant shorter time to discharge with treatment.
Nov 2021, medRxiv, https://www.medrxiv.org/content/10.1101/2021.11.08.21265884v1, https://c19p.org/shenoy

61. Iwata et al., Findings from a discontinued clinical trial of favipiravir in high-risk patients with early-onset COVID-19

86 patient favipiravir early treatment RCT: 16% higher need for oxygen therapy (p=0.73) and 16% worse viral clearance (p=0.66).
Early terminated RCT 84 patients in Japan, showing no significant difference in outcomes with favipiravir treatment. There was a trend for improved efficacy for patients enrolled within 48 hours of symptom onset.
Oct 2023, J. Infection and Chemotherapy, https://www.sciencedirect.com/science/article/pii/S1341321X23002556, https://c19p.org/iwata

62. Chandiwana et al., Safety and efficacy of four drug regimens versus standard-of-care for the treatment of symptomatic outpatients with COVID-19: A randomised, open-label, multi-arm, phase 2 clinical trial

76 patient favipiravir early treatment RCT: 13% higher progression (p=0.89), 23% slower recovery (p=0.42), and 67% worse viral clearance (p=0.13).
Very high COI low-risk patient RCT in South Africa, showing no significant differences with favipiravir plus nitazoxanide. There were no deaths and no COVID-19 hospitalizations for favipiravir plus nitazoxanide. More patients were seropositive at baseline in the treatment arm (28% vs 22%). Favipiravir 1600mg 12-hourly for 1 day, then 600mg 12-hourly for 6 days. Nitazoxanide 1000mg 12-hourly for 7 days.
Oct 2022, eBioMedicine, https://www.sciencedirect.com/science/article/pii/S2352396422005047, https://c19p.org/chandiwana

63. McMahon et al., Favipiravir in early symptomatic COVID-19, a randomised placebo-controlled trial

199 patient favipiravir early treatment RCT: 1% higher need for oxygen therapy (p=1) and 56% higher hospitalization (p=0.38).
RCT with 99 favipiravir and 100 placebo patients in Australia, all except one being outpatients, showing no significant differences with treatment.
Jun 2022, eClinicalMedicine, https://www.thelancet.com/journals/eclinm/article/PIIS2589-5370(22)00433-3/fulltext, https://c19p.org/mcmahon

64. Lowe et al., Favipiravir, lopinavir-ritonavir, or combination therapy (FLARE): A randomised, double-blind, 2 × 2 factorial placebo-controlled trial of early antiviral therapy in COVID-19

119 patient favipiravir early treatment RCT: 28% improved viral clearance (p=0.03).
240 patient RCT comparing favipiravir, favipiravir + LPV/r, LPV/r, and placebo, showing improved viral clearance with favipiravir. Efficacy was lower in the combined favipiravir + LPV/r arm, where plasma levels of favipiravir were lower. Favipiravir 1800mg twice daily on day 1 followed by 400mg four times daily on days 2-7.
Feb 2022, PLOS Medicine, https://journals.plos.org/plosone/article?id=10.1371/journal.pmed.1004120, https://c19p.org/lowe

65. Finberg et al., US201 Study: A Phase 2, Randomized Proof-of-Concept Trial of Favipiravir for the Treatment of COVID-19

50 patient favipiravir late treatment RCT: 20% longer hospitalization, 58% improved recovery (p=0.08), and 47% faster viral clearance (p=0.04).
Small very late treatment RCT in the USA, with 25 favipiravir and 25 control patients, showing faster viral clearance with treatment. The benefit was only seen in patients <8 days from symptom onset. There were no significant differences in clinical outcomes. The death in the favipiravir group occurred after discharge and was believed to be unrelated to COVID-19 or favipiravir.
Dec 2021, Open Forum Infectious Diseases, https://academic.oup.com/ofid/article/8/12/ofab563/6455602, https://c19p.org/finberg

66. Lou et al., Clinical Outcomes and Plasma Concentrations of Baloxavir Marboxil and Favipiravir in COVID-19 Patients: An Exploratory Randomized, Controlled Trial

19 patient favipiravir late treatment RCT: 422% higher ICU admission (p=0.21), 11% improved recovery (p=1), and 422% worse viral clearance (p=0.21).
Small late stage RCT with 10 favipiravir, 10 baloxavir marboxil, and 10 control patients in China, showing no significant differences.
Oct 2020, European J. Pharmaceutical Sciences, https://www.sciencedirect.com/science/article/pii/S092809872030419X, https://c19p.org/lou

67. Horcajada et al., Safety and efficacy of favipiravir in COVID-19 patients with pneumonia. A randomized, double-blind, placebo-controlled study (FAVID)

44 patient favipiravir late treatment RCT: 383% higher mortality (p=0.49), 37% higher ventilation (p=1), no change in improvement (p=0.45), and 17% improved recovery (p=0.64).
Underpowered RCT with 44 hospitalized patients in Spain, showing no significant difference with favipiravir treatment in the primary outcome of time to clinical improvement, or in the secondary efficacy outcomes. Adverse events were more frequent in the favipiravir group (68%) compared to placebo (32%), but most were mild.
Aug 2023, Pneumonia, https://pneumonia.biomedcentral.com/articles/10.1186/s41479-023-00124-6, https://c19p.org/horcajada

68. Chuah et al., Efficacy of Early Treatment with Favipiravir on Disease Progression among High Risk COVID-19 Patients: A Randomized, Open-Label Clinical Trial

500 patient favipiravir late treatment RCT: 1154% higher mortality (p=0.08), 20% higher ventilation (p=0.76), and 9% higher ICU admission (p=0.84).
RCT 500 hospitalized patients in Malaysia, showing no significant differences with favipiravir treatment.
Nov 2021, Clinical Infectious Diseases, https://academic.oup.com/cid/advance-article/doi/10.1093/cid/ciab962/6432025, https://c19p.org/chuah

69. Ivashchenko et al., AVIFAVIR for Treatment of Patients with Moderate COVID-19: Interim Results of a Phase II/III Multicenter Randomized Clinical Trial

60 patient favipiravir late treatment RCT: 46% improved viral clearance (p=0.03) and 67% lower hospital discharge (p=0.51).
Interim results for a small RCT with 40 favipiravir and 20 control patients showing faster viral clearance with favipiravir. There is limited data in this report to evaluate the results. 75% of the control group received HCQ/CQ.
Aug 2020, Clinical Infectious Diseases, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7454388/, https://c19p.org/ivashchenko

70. Bosaeed et al., Efficacy of favipiravir in adults with mild COVID-19: a randomized, double-blind, multicenter, placebo-controlled trial clinical trial

231 patient favipiravir early treatment RCT: 619% higher ICU admission (p=0.11), 219% higher hospitalization (p=0.16), 12% slower recovery (p=0.51), and 15% slower viral clearance (p=0.51).
RCT with 112 favipiravir and 119 control patients showing no significant differences in outcomes. Viral clearance and clinical recovery for patients treated within 48 hours was better than those treated later. NCT04464408.
Jan 2022, Clinical Microbiology and Infection, https://www.sciencedirect.com/science/article/pii/S1198743X21007345, https://c19p.org/bosaeed2

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