However, the Lancet paper isn't the only study that has been released on the effects of HCQ on COVID-19. There have been multiple studies performed globally over the months about the effectiveness of the medication on patients in different stages of the disease, from post-exposure to hospitalization. Here's seven (EDIT: eight) I found that have shown that HCQ has either no effect or worse effects on patients vs. a hospital's standard of care (and a ninth one that was supposed to confirm HCQ's benefit, but couldn't).
Hydroxychloroquine with or without Azithromycin in Mild-to-Moderate Covid-19 - Brazil, July 2020. 55 hospitals underwent this randomized study of 667 patients (504 with confirmed COVID-19). They received either a regular standard of care, standard of care + HCQ, or standard of care + HCQ + azithromycin. The study showed that neither treatement option improved patient's chances 15 days after the beginning of treatment.
No clinical benefit from use of hydroxychloroquine in hospitalised patients with COVID-19 - United Kingdom, June 2020. 1542 patients were randomized with hydroxycholoruine and 3132 were randomized to a standard-of-care treatment alone. Doctors found that "There was no significant difference in the primary endpoint of 28-day mortality. There was also no evidence of beneficial effects on hospital stay duration or other outcomes."
A Randomized Trial of Hydroxychloroquine as Postexposure Prophylaxis for Covid-19 - United States, June 3, 2020. A double-blind, placebo-controlled trial on the post-exposure prophylactic effects of HCQ. Of the 821 people enrolled, no positive effect was found on the prevention of COVID-19 symptoms.
Treatment of COVID-19 Cases and Chemoprophylaxis of Contacts as Prevention (HCQ4COV19) - Spain, March-June 2020. A group of ~3030 enrolled to study the the post-exposure prophylactic effects of HCQ. On its last update, the study found there was no significant difference between the number of people in each group who developed COVID-19. The study will finish on the 15th of June , where a final verdict will be known.
Observational Study of Hydroxychloroquine in Hospitalized Patients with Covid-19 - United States, May 2020. 1376 hospital patients were observed. 811 were given HCQ, the rest weren't. There was no significant association between hydroxycholroquine use and intubation or death.
Effect of High vs Low Doses of Chloroquine Diphosphate as Adjunctive Therapy for Patients Hospitalized With Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Infection - Brazil, April 2020. 81 patients enrolled. Stopped after an interim analysis found that a higher dosage of chloroquine diphosphate for 10 days was associated with more toxic effects and lethality.
Outcomes of hydroxychloroquine usage in United States veterans hospitalized with Covid-19 - United States, April 2020. 368 COVID-19 patients were part of a retrospective study with treatments of HCQ, HCQ+azithromycin, and nothing. The study found no evidence that use of hydroxychloroquine, either with or without azithromycin, reduced the risk of mechanical ventilation in patients hospitalized with Covid-19. An association of increased overall mortality was identified in patients treated with hydroxychloroquine alone.
Hydroxychloroquine in patients mainly with mild to moderate COVID-19: an open-label, randomized, controlled trial - China, February-May 2020. In February, 75 patients were given HCQ while 75 were a control group. The study found that administration of HCQ did not result in a significantly higher negative conversion probability than standard-of-care alone in patients mainly hospitalized with persistent mild to moderate COVID-19. Also, adverse events were higher in HCQ recipients than in HCQ non-recipients.
NOTE: While I was looking around for HCQ/COVID-19 studies, there were a couple I found that show the drug has *some* benefit on people suffering from COVID-19. These are actual studies, not rando doctors spitting unverified anecdotes in hopes of getting fame. The studies themselves are subject to some scrutiny (sample size, different standards of care for different groups of patients), but in the interest of transparency, I will still include them below:
Treatment with hydroxychloroquine, azithromycin, and combination in patients hospitalized with COVID-19 - United States, July 2020. From 2,541 patients, it was shown that HCQ + azithromycin actually improved a patient's chances. It's important to note that the study did not control for steroid use in a patient's standard of care, as it also points out that patient's conditions improve upon use of steroids (and that may have tainted the end result).
Hydroxychloroquine and azithromycin as a treatment of COVID-19: results of an open-label non-randomized clinical trial - France, March 2020. 36 hospitalized COVID-19 patients were in this study, where 20 were treated with HCQ (of these, 6 were also given azithromycin) and 16 were the control group. After five days, half of the HCQ patients and all the HCQ+azithromycin patients were virologicaly cured. A second study was done to confirm the results of the first, but showed no evidence on the benefit of HCQ+azithromycin.
Efficacy of hydroxychloroquine in patients with COVID-19: results of a randomized clinical trial - China, March 2020. A small, randomized study of 62 people in Wuhan, China looked at how well hydroxychloroquine worked for hospitalized patients with mild COVID-19. Cough and fever improved about 1 day earlier for those who got 400 mg of hydroxychloroquine for 5 days compared to those who did not get any. Additionally, pneumonia improved in 25 of 31 patients who received hydroxychloroquine (compared to 17 of 31 in the group who didn't).
This is in no way an exhaustive list of studies on HCQ's effect on COVID-19, but I hope it helps educate people on both sides that research is both continuing and ultimately inconclusive on the drug's efficacy in this situation.