A 2-Part, 2-Arm, Phase 2, Randomized, Double-Blind, Placebo-Controlled Study on the Safety and Efficacy of Niclosamide in Patients With COVID-19 With Gastrointestinal Infection

First Wave BioPharma, NCT04858425, RESERVOIR, NCT04858425, May 2023
Viral clearance, day 43 23% improvement lower risk ← → higher risk Viral clearance, day 36 33% Viral clearance, day 29 42% Viral clearance, day 22 27% Viral clearance, day 15 23% Viral clearance, day 8 1% Viral clearance, day 4 -3% Niclosamide  RESERVOIR  LATE TREATMENT RCT Is late treatment with niclosamide beneficial for COVID-19? Double-blind RCT 118 patients in the USA Trial underpowered to detect differences c19early.org First Wave BioPharma, NCT04858425, May 2023 0 0.5 1 1.5 2+ RR
55th treatment shown to reduce risk in August 2025, now with p = 0.0069 from 7 studies.
Lower risk for recovery.
No treatment is 100% effective. Protocols combine treatments.
6,300+ studies for 210+ treatments. c19early.org
Meta Analysis
RCT 118 hospitalized patients with gastrointestinal infection showing no significant difference in viral clearance with niclosamide. Viral clearance results are available on clinicaltrials.gov but clinical results are missing.
Viral load measured by PCR may not accurately reflect infectious virus measured by viral culture. Porter et al. show that viral load early in infection was correlated with infectious virus, but viral load late in infection could be high even with low or undetectable infectious virus. Assessing viral load later in infection may underestimate reductions in infectious virus with treatment.
Standard of Care (SOC) for COVID-19 in the study country, the USA, is very poor with very low average efficacy for approved treatments2. Only expensive, high-profit treatments were approved for early treatment. Low-cost treatments were excluded, reducing the probability of early treatment due to access and cost barriers, and eliminating complementary and synergistic benefits seen with many low-cost treatments.
Important missing comments or errors? Let us know.
risk of no viral clearance, 22.7% lower, RR 0.77, p = 0.61, treatment 8 of 60 (13.3%), control 10 of 58 (17.2%), NNT 26, day 43.
risk of no viral clearance, 33.1% lower, RR 0.67, p = 0.35, treatment 9 of 60 (15.0%), control 13 of 58 (22.4%), NNT 13, day 36.
risk of no viral clearance, 42.0% lower, RR 0.58, p = 0.17, treatment 9 of 60 (15.0%), control 15 of 58 (25.9%), NNT 9.2, day 29.
risk of no viral clearance, 27.5% lower, RR 0.73, p = 0.39, treatment 12 of 60 (20.0%), control 16 of 58 (27.6%), NNT 13, day 22.
risk of no viral clearance, 22.7% lower, RR 0.77, p = 0.34, treatment 20 of 60 (33.3%), control 25 of 58 (43.1%), NNT 10, day 15.
risk of no viral clearance, 0.8% lower, RR 0.99, p = 1.00, treatment 39 of 60 (65.0%), control 38 of 58 (65.5%), NNT 193, day 8.
risk of no viral clearance, 2.6% higher, RR 1.03, p = 0.80, treatment 52 of 60 (86.7%), control 49 of 58 (84.5%), day 4.
Effect extraction follows pre-specified rules prioritizing more serious outcomes. Submit updates
First Wave BioPharma et al., 1 May 2023, Double Blind Randomized Controlled Trial, placebo-controlled, USA, preprint, 1 author, trial NCT04858425 (history) (RESERVOIR).
$0 $500 $1,000+ Efficacy vs. cost for COVID-19 treatment protocols c19early.org December 2025 USA Russia Sudan Angola Colombia Kenya Mozambique Vietnam Peru Philippines Spain Brazil Italy France Japan Canada China Uzbekistan Nepal Ethiopia Iran Ghana Mexico South Korea Germany Bangladesh Saudi Arabia Algeria Morocco Yemen Poland India DR Congo Madagascar Thailand Uganda Venezuela Nigeria Egypt Bolivia Taiwan Zambia Fiji Bosnia-Herzegovina Ukraine Côte d'Ivoire Bulgaria Greece Slovakia Singapore Iceland New Zealand Czechia Mongolia Israel Trinidad and Tobago Hong Kong North Macedonia Belarus Qatar Panama Serbia CAR USA favored high-profit treatments.The average efficacy of treatments was very low.High-cost protocols reduce early treatment, andforgo complementary/synergistic benefits. More effective More expensive 75% 50% 25% ≤0%
$0 $500 $1,000+ Efficacy vs. cost for COVID-19treatment protocols worldwide c19early.org December 2025 USA Russia Sudan Angola Colombia Kenya Mozambique Vietnam Peru Philippines Spain Brazil Italy France Japan Canada China Uzbekistan Nepal Ethiopia Iran Ghana Mexico South Korea Germany Bangladesh Saudi Arabia Algeria Morocco Yemen Poland India DR Congo Madagascar Thailand Uganda Venezuela Nigeria Egypt Bolivia Taiwan Zambia Fiji Ukraine Côte d'Ivoire Eritrea Bulgaria Greece Slovakia Singapore New Zealand Malawi Czechia Mongolia Israel Trinidad and Tobago North Macedonia Belarus Qatar Panama Serbia Syria USA favored high-profit treatments.The average efficacy was very low.High-cost protocols reduce early treatment,and forgo complementary/synergistic benefits. More effective More expensive 75% 50% 25% ≤0%
Late treatment
is less effective
Please send us corrections, updates, or comments. c19early involves the extraction of 200,000+ datapoints from thousands of papers. Community updates help ensure high accuracy. Treatments and other interventions are complementary. All practical, effective, and safe means should be used based on risk/benefit analysis. No treatment or intervention is 100% available and effective for all current and future variants. 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. IMA and WCH provide treatment protocols.
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