Three of the four authors of the controversial paper published in the Lancet on the use of hydroxychloroquine against the Covid-19 have requested the retraction of the article, announced that the journal The Lancet on Thursday evening.

"We can't vouch for the veracity of the sources of primary data," write the three authors to the Lancet, involving the refusal of the fourth, the boss of the company which collected it, to give access to the database.