Research shows that a blood-thinning drug given to patients recovering from Covid can cause major bleeding.
The findings have led to calls for doctors to stop advising people to take Apixaban because it does not stop them from dying or ending up back in hospital.
When a patient is discharged from the hospital after being treated for Covid, they are given the anticoagulant. Hospitals use it all the time in the National Health Service.
The Heal- Covid trial was funded by the UK government.
The first findings from the trial show that a blood-thinning drug is not effective at stopping people from dying or being readmitted to hospital.
It will prevent unnecessary harm occurring to people for no benefit.
The trial is the first to show that longer anticoagulation after Covid-19 puts patients at risk for no benefit.
The hope is that these results will stop patients from being prescribed Covid-19 in the first place.
If you're discharged from the hospital with Covid, you should be given Apixaban for 14 days, even if you don't go home.
Doctors hoping to find effective treatments against Covid hoped that the drug would decrease the risk of blood clot. Some of the participants in the trial who received the blood thinner suffered serious bleeding that caused them to come off the drug.
More than 30% of Covid patients who received standard care ended up back in hospital within a year, but only a small percentage of those on Apixaban did so.
When it synthesised the evidence around the drug in 2020, it found no clinical trials of its use in discharged Covid patients, but it still recommended its use. 11 different countries issued guidelines that endorsed its use.