COVID-19 is an infectious respiratory disease caused by a coronavirus called SARS-CoV-2. If the infection becomes severe, people may need intensive care and support in hospital, including mechanical ventilation.
Drugs used for other diseases were tried out in COVID-19, and this included chloroquine, used for malaria; and hydroxychloroquine used for rheumatic diseases, such as rheumatoid arthritis or systemic lupus erythematosus. The authors sought evidence of the effects of these drugs in treating people ill with the disease; in preventing the disease in people at risk of getting the disease, such as health workers; and people exposed to the virus developing the disease.
- Hydroxychloroquine does not reduce deaths from COVID-19, and probably does not reduce the number of people needing mechanical ventilation.
- Hydroxychloroquine caused more unwanted effects than a placebo treatment, though it did not appear to increase the number of serious unwanted effects.
- The authors do not think new studies of hydroxychloroquine should be started for treatment of COVID-19.
Bhagteshwar Singh, Lead author of this review and Clinical Research Fellow at the Institute of Infection, Veterinary & Ecological Sciences, University of Liverpool explains,
“Early in the pandemic, chloroquine and hydroxychloroquine had been put forward as potential drugs for treatment and prevention of COVID-19. Evidence from initial studies was inadequate, but more recent reports from larger trials meant we could conclude in our review that hydroxychloroquine is not beneficial for patients with COVID-19 who require care in hospital. The evidence is less clear for prevention of COVID-19 and for people being treated as outpatients. However, with no benefit when used for treatment of severe COVID-19, a benefit in these situations is unlikely.”
Senior author Dr Tom Fletcher added: “This review certainly should put a line under using this drug to treat COVID-19, but some countries and health providers are still caught up in the earlier hype and prescribing the drug. We hope this review will help these practices end soon."
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What was studied in the review?
The team searched for studies that looked at giving chloroquine and hydroxychloroquine to people with COVID-19; people at risk of being exposed to the virus; and people who have been exposed to the virus.
They found 14 relevant studies: 12 studies of chloroquine or hydroxychloroquine used to treat COVID-19 in 8569 adults; two studies of hydroxychloroquine to stop COVID-19 in 3346 adults who had been exposed to the virus but had no symptoms of infection. The authors did not find any completed studies of these medicines to stop COVID-19 in people who were at risk of exposure to the virus; studies are still under way.
The studies took place in China, Brazil, Egypt, Iran, Taiwan, North America, and Europe; one study was worldwide. Some studies were partly funded by pharmaceutical companies that manufacture hydroxychloroquine.