British Journal of General Practice, 2020 Jun; 4(2)
This is another review of studies published by March 2020, and only 3 studies were discussed. They are listed in Table 1 in the document.
Of these three studies, the one from China (Gao et al, 2020) was a letter to BioScience Trends, reporting on the treatment of more than 100 patients. They reported that CQ was better than the “control” treatment because it shortened the disease and prevented pneumonia. Based on their findings, regulatory authorities agreed to include it in the treatment of COVID-19 in China.
A study in France (Gautret et al, 2020) of 36 people testing positive, 20 were given 200 mg HCQ 3 times a day (TID) for 10 days, with 6 given azithromycin as well, and 16 were the “controls.” 70% of the treatment group were cured by Day 6, compared to 12% of the controls, given only supportive care (see chart above). All 6 of those given both HCQ + Azithromycin tested negative on Day 6. Although the difference between groups is very dramatic, they were not randomly allocated, so the authors suggest there could have been bias.
Another Chinese study (Chen et al, 2020) involved 30 people over 18 who tested positive and were hospitalized. They were given 400 mg/day of HCQ for 5 days. There was almost no difference between the treated and control groups when they were retested on Day 7. 
NOTE: This is not surprising considering that Garcia-Cremades (2020) made a chart of results of various dosages, and this dosage had the least effect of all but the control (see the pink column when you click on this chart to enlarge it.)
Gbinigie et al complain that none of the studies were done in regular doctor practices but only in hospitals, and that more research is needed since (as of March) there was insufficient evidence to support the use of CQ or HCQ except for research.
Conflict of Interest: This review was funded by the Wellcome Trust, a pharmaceutical company fund.
Links to papers reviewed:
- Gao et al (2020) – Breakthrough: Chloroquine phosphate has shown apparent efficacy in treatment of COVID-19 associated pneumonia in clinical studies
- Gautret et al (2020) – Hydroxychloroquine and azithromycin as a treatment of COVID-19: Results of an open-label non-randomized clinical trial
- Chen et al (2020) – Efficacy of hydroxychloroquine in patients with COVID-19: Results of a randomized clinical trial
