The results of a clinical trial testing the use of blood plasma taken from people recovering from coronavirus, known as "convalescent plasma", has no benefit in treating COVID-19 patients.

After studies were conducted in India, the results published in the British Medical Journal Friday, showed that convalescent plasma which transports antibodies from those recovering from COVID-19 to infected patients "did not succeed in reducing death rates or preventing severe infection symptoms".

Results of the trial, which included a study of more than 400 COVID-19 patients, represented a setback to the treatment method that US President Donald Trump described August as a “historical development”.

The United States and India currently allow the use of convalescent plasma in emergency situations and Britain is collecting plasma from donors so that it can be used on a large scale if it is proven effective.

Simon Clark, an expert in cellular microbiology at the University of Reading said, "The experiments showed little effect on the rate at which patients clear the virus, but this was not sufficient to increase their level of recovery from the sickness."

He added, "In simple terms, there were no clinical benefits for patients."

The Indian researchers conducted the study on 464 adults with moderate cases of coronavirus, who were transferred to hospitals across India between April and July.

The researchers randomly divided the subjects into two groups, where the first group got convalescent plasma twice, at a 24-hour interval, along with the best possible care, while the other group got nothing but care.

A week later, researchers said that the use of convalescent plasma appeared to note improvement of some symptoms such as shortness of breath and fatigue.

There were also higher rates of what is known as a "negative shift", which is a sign that the antibodies are neutralizing the virus, but this did not translate into a decrease in mortality or preventing COVID-19 from reaching dangerous stages.

"The poor performance of convalescent plasma in this experiment is disappointing, but it is not entirely surprising," said Ian Jones, professor of virology at the University of Reading.

He added that the plasma is likely to yield results if given directly after being infected with COVID-19.