It was investigated in the world’s largest clinical trial of treatments for patients hospitalised with COVID-19.
Oxford University experts tested out the effects of asprin, which is widely used to reduce blood clotting in other diseases, on nearly 15,000 patients between November 2020 and March 2021.
Coronavirus patients are at an increased risk of blood clots forming in their blood vessels, particularly their lungs.
A total of 7351 patients were given aspirin 150 mg once a day while 7541 patients were provided usual care.
The experts found that there was no evidence that aspirin treatment reduced mortality.
Patients given aspirin had a slightly shorter duration of hospitalisation and a higher proportion were discharged from hospital alive within 28 days.
But, there was no significant difference in the proportion who needed ventilators, according to the research.
It found that for every 1000 patients treated with aspirin, approximately 6 more patients experienced a major bleeding and approximately 6 fewer experienced a thromboembolic (clotting) event.
Peter Horby, Professor of Emerging Infectious Diseases in the Nuffield Department of Medicine, University of Oxford, and Joint Chief Investigator for the RECOVERY trial, said: 'The data show that in patients hospitalised with COVID-19, aspirin was not associated with reductions in 28-day mortality or in the risk of progressing to invasive mechanical ventilation or death. Although aspirin was associated with a small increase in the likelihood of being discharged alive this does not seem to be sufficient to justify its widespread use for patients hospitalised with COVID-19.'
Martin Landray, Professor of Medicine and Epidemiology at the Nuffield Department of Population Health, University of Oxford, and Joint Chief Investigator, said: 'There has been a strong suggestion that blood clotting may be responsible for deteriorating lung function and death in patients with severe COVID-19. Aspirin is inexpensive and widely used in other diseases to reduce the risk of blood clots so it is disappointing that it did not have a major impact for these patients. This is why large randomised trials are so important - to establish which treatments work and which do not.
'As ever, we are enormously grateful to the thousands of medical staff and patients who have contributed to the RECOVERY trial, helping to find better treatments for patients all around the world.'