An influential article in the British medical journal The Lancet found hydroxychloroquine increased the risk of death in COVID-19 patients.

Now, three of its authors have retracted their study on concerns about the quality of the data.

According to Reuters, Surgisphere was the company that provided the data.

However, the authors say Surgisphere would not transfer the full dataset for an independent review.

As such, they say they can 'no longer vouch for the veracity of the primary data sources.'