The UK clinical trial into the impact of hydroxychloroquine on Covid-19 'will continue', the Department of Health (DH) has said after researchers retracted a paper that had indicated the treatment was unsafe.

The MHRA halted recruitment to the PRINCIPLE trial - led by the University of Oxford and including almost 800 GP practices - last week, after the Lancet published a study that found hydroxychloroquine increases the risk of death in Covid-19 patients.

However, since then researchers had questioned the data quality of the study- which also prompted the WHO to halt trials - and yesterday three of the paper's authors decided to retract their paper because they could not ‘vouch for the veracity of the primary data sources’.

This came as Surgisphere, an American healthcare company whose chief executive was the fourth author of the paper, would not transfer the full data-set, client contracts, or audit reports needed for an independent, private peer-review. 

Following the retraction, the Lancet said in a statement: 'The Lancet takes issues of scientific integrity extremely seriously, and there are many outstanding questions about Surgisphere and the data that were allegedly included in this study. Following guidelines from the Committee on Publication Ethics (COPE) and International Committee of Medical Journal Editors (ICMJE), institutional reviews of Surgisphere’s research collaborations are urgently needed.’

The three authors added: ‘We always aspire to perform our research in accordance with the highest ethical and professional guidelines. We can never forget the responsibility we have as researchers to scrupulously ensure that we rely on data sources that adhere to our high standards. Based on this development, we can no longer vouch for the veracity of the primary data sources. Due to this unfortunate development, the authors request that the paper be retracted.

‘We all entered this collaboration to contribute in good faith and at a time of great need during the Covid-19 pandemic. We deeply apologise to you, the editors, and the journal readership for any embarrassment or inconvenience that this may have caused.’

Speaking in a GP webinar last night, England’s deputy chief medical officer Dr Jenny Harries stressed that the UK trials into hydroxychloroquine will continue, with ‘appropriate safeguards’.

She said: ‘Despite some of the uncertainty around trials on chloroquine, the big publication that created a little bit of noise in the media a couple of weeks ago has been reviewed possibly a bit more thoroughly. So those trials will continue with all the appropriate safeguards that we have in the UK.’

It comes as the BMJ has published papers on other studies which suggested hydroxychloroquine has 'no effect' on Covid-19 recovery, or may even have adverse effects.