An observational study by researchers at Columbia University found that hydroxychloroquine had limited impact on the intubation or death outcomes of Covid-19 patients.

The research was carried out on 1,446 patients at a large hospital in New York City and the findings were published in the New England Journal of Medicine. It was partly funded by grants from the US National Institutes of Health.

“In this analysis involving a large sample of consecutive patients who had been hospitalized with Covid-19, the risk of intubation or death was not significantly higher or lower among patients who received hydroxychloroquine than among those who did not,” the authors concluded. “Our findings do not support the use of hydroxychloroquine at present, outside randomized clinical trials testing its efficacy.”

As a result of these findings, clinical guidance at the hospital where the research was conducted have been updated to remove the suggestion that hydroxychloroquine can be used to treat Covid0-19 patients.