In yet another blow to slim hopes that hydroxychloroquine may have some value as a treatment for Covid-19, experts have found that taking the drug before coronavirus exposure does not reduce the risk of mortality.
Previous studies have shown that the 70-year-old malaria drug has no benefit when used as a treatment for patients suffering from Covid-19, or as a postexposure prophylaxis – that is, to prevent people developing an infection after coming into contact with the virus.
But the latest observational study, published in Lancet Rheumatology on Thursday, is the first of its kind to assess whether hydroxychloroquine reduces fatalities if given before an individual comes into contact with Covid.
The research used anonymised data from an analytics platform called OpenSAFELY to track some 30,000 patients who had been prescribed hydroxychloroquine to treat rheumatoid arthritis or lupus for at least six months before the pandemic first reached the UK.
Of this group, 70 died from Covid-19 between March and June. The researchers found there was no statistical difference between this mortality rate and that in a control group of people who had rheumatoid arthritis or lupus but did not take hydroxychloroquine.
“We found no association between hydroxychloroquine use and Covid mortality,” said Dr Christopher Rentsch, a pharmacoepidemiologist at the London School of Hygiene and Tropical Medicine and lead author of the report.