Hydroxychloroquine in the Prevention of COVID-19 Infection in Healthcare Workers

McCullough et al., NCT04333225, Aug 2021
Case 52% improvement lower risk ← → higher risk HCQ for COVID-19  McCullough et al.  PROPHYLAXIS Is pre-exposure prophylaxis with HCQ beneficial for COVID-19? Prospective study of 221 patients in the USA Fewer cases with HCQ (p=0.012) c19early.org McCullough et al., NCT04333225, August 2021 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
Download Meta Analysis
Prospective study with 221 healthcare workers, showing lower risk of COVID-19 with HCQ prophylaxis.
Standard of Care (SOC) for COVID-19 in the study country, the USA, is very poor with very low average efficacy for approved treatments1. 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 case, 51.7% lower, RR 0.48, p = 0.01, treatment 13 of 101 (12.9%), control 32 of 120 (26.7%), NNT 7.2.
Effect extraction follows pre-specified rules prioritizing more serious outcomes. Submit updates
McCullough et al., 20 Aug 2021, prospective, USA, preprint, 1 author.
$0 $500 $1,000+ Efficacy vs. cost for COVID-19 treatment protocols c19early.org November 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 November 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%
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.
  or use drag and drop   
Submit    
Post
Share
@CovidAnalysis
FAQ
Public domain CC0 1.0