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

Zhong Nanshan, 3/26, Mar 2020
Late treatmentRetrospective · 197 patients · China
HCQ for COVID-19
Zhong Nanshan 3/26 · March 2020
Outcome
Improvement
Relative Risk · 95% CI
Virological cure at day 10
80%0.20 · 0.08–0.55
00.511.52+
← HCQ reduces riskIncreased risk →
Improved viral clearance with HCQ
p = 0.0001

HCQ for COVID-19

1st treatment shown to reduce risk in March 2020, now with p < 0.0000000001 from 425 studies, used in 59 countries.
Lower risk for mortality, hospitalization, progression, recovery, cases, and viral clearance.

No treatment is 100% effective.
Protocols combine treatments.

6,700+ studies · 220+ treatments

c19early.org
Meta-analysis
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.
Important missing comments or errors? Let us know.
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 October 2026 China Angola Colombia Kenya Mozambique Myanmar South Africa Peru Philippines USA Brazil France Italy Canada Pakistan Spain Vietnam Japan Nepal Iran Bangladesh Ethiopia Ghana Germany Mexico South Korea United Kingdom Saudi Arabia Algeria Morocco Yemen Poland Thailand Uganda Egypt Nigeria Taiwan Fiji Zambia Bosnia-Herzegovina Dominican Republic Bolivia Côte d'Ivoire Eritrea Togo Bulgaria Greece Slovakia Iceland New Zealand Trinidad and Tobago Mongolia Czechia Belarus Israel Haiti North Macedonia Hong Kong Qatar Panama Serbia Benin Burundi Cameroon 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 October 2026 China Angola Colombia Kenya Mozambique Myanmar South Africa Peru Philippines USA Brazil France Italy Canada Pakistan Spain Vietnam Japan Iran Bangladesh Ethiopia Ghana Germany Mexico South Korea United Kingdom Saudi Arabia Algeria Morocco Yemen Poland Thailand Uganda Egypt Nigeria Taiwan Fiji Zambia Dominican Rep. Bolivia Côte d'Ivoire Eritrea Togo Sri Lanka Bulgaria Greece Slovakia New Zealand Trinidad and Tobago Mongolia Czechia Belarus Israel North Macedonia Hong Kong Qatar Panama Serbia Benin Burundi CAR 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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