The University of Oxford has added aspiring as a potential treatment for COVID-19 as part of the RECOVERY trial.
Researchers said that patients with the virus are at higher risk of blood clots forming in their blood vessels, because certain small cell fragments in the blood seem to be hyperreactive and may be involved in the clotting complications.
Aspirin could therefore help with reducing the risk of blood clots.
At least 2,000 patients will be randomly allocated to receive aspirin 150 mg daily plus usual standard-of-care, and results will be compared with at least 2,000 patients who receive standard-of-care on its own.
Participants will not receive aspirin if they are known to be hypersensitive to it.
The main outcome will be to assess mortality after 28 days, alongside impact on hospital stay and the need for ventilation.
The university said it is likely to be several months before there is enough evidence to conclude whether aspirin has a significant benefit in COVID-19 patients.
The wider RECOVERY trial is based in 176 hospital sites across the UK and has so far recruited over 16,000 patients.
It is currently assessing antibiotic azithromycin, anti-inflammatory treatment tocilizumab, convalescent plasma and an investigational antibody cocktail produced by NASDAQ-listed Regeneron.
“We felt it was particularly important to add aspirin to the trial since there is a clear rationale for believing that it might be beneficial and it is safe, inexpensive and widely available,” said Professor Peter Horby, co-chief Investigator of the trial.
“We are looking for medicines for COVID-19 that can be used immediately by anyone, anywhere in the world. We do not know if aspirin is such a medicine but we will find out.”