Efficacy and safety of chloroquine for treatment of COVID-19. An open-label, multi-center, non-randomized trial

Zhong Nanshan, Mar 2020
Virological cure at day.. 80% improvement lower risk ← → higher risk HCQ  Zhong Nanshan et al.  LATE TREATMENT Is late treatment with HCQ beneficial for COVID-19? Retrospective 197 patients in China Improved viral clearance with HCQ (p=0.0001) c19early.org Zhong Nanshan, March 2020 0 0.5 1 1.5 2+ RR
HCQ for COVID-19
1st treatment shown to reduce risk in March 2020, now with p < 0.00000000001 from 424 studies, used in 59 countries.
Lower risk for mortality, hospitalization, progression, recovery, cases, and viral clearance.
No treatment is 100% effective. Protocols combine treatments.
6,200+ studies for 200+ treatments. c19early.org
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197 patients. CQ effective. Day 10 viral RNA negative 91.4% HCQ versus 57.4% control. Median time to negative test 3 days versus 9 days for control.
Standard of Care (SOC) for COVID-19 in the study country, China, is average with moderate efficacy for approved treatments1.
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risk of no virological cure at day 10, 80.0% lower, RR 0.20, p < 0.001, treatment 5 of 115 (4.3%), control 17 of 82 (20.7%), NNT 6.1, adjusted per study.
Effect extraction follows pre-specified rules prioritizing more serious outcomes. Submit updates
Zhong Nanshan et al., 26 Mar 2020, retrospective, China, preprint, 1 author.
$0 $500 $1,000+ Efficacy vs. cost for COVID-19 treatment protocols c19early.org November 2025 China United Kingdom Russia USA Sudan Angola Colombia Kenya Mozambique Pakistan Argentina Vietnam Peru Philippines Spain Brazil Italy France Japan 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 Côte d'Ivoire Eritrea Bulgaria Greece Slovakia Singapore Iceland New Zealand Czechia Mongolia Israel Trinidad and Tobago Hong Kong North Macedonia Belarus Qatar Panama Serbia CAR China favored low-cost treatments.The average efficacy of treatments was moderate.Low-cost treatments improve early treatment, andprovide 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 November 2025 China United Kingdom Russia USA Sudan Angola Colombia Kenya Mozambique Pakistan Argentina Vietnam Peru Philippines Spain Brazil Italy France Japan 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 Côte d'Ivoire Eritrea Togo Bulgaria Greece Slovakia Singapore New Zealand Malawi Czechia Mongolia Israel Trinidad and Tobago North Macedonia Belarus Qatar Panama Serbia Syria China favored low-cost treatments.The average efficacy was moderate.Low-cost protocols improve early treatment,and add 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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