New York, Aug 21 (IANS): Blood plasma therapy that is being touted as the final resort to treat Covid-19 has not convinced the US Food and Drug Administration (FDA) as it has put the emergency use authorisation for blood plasma to treat the deadly respiratory disease on hold, the media reported.

According to a report in The New York Times on Thursday, the FDA approval for plasma therapy is on hold and "more data is under review and the approval could still be issued in the near future, according to H. Clifford Lane, the clinical director at the National Institute of Allergy and Infectious Diseases".

According to the report, senior federal health officials said data supporting the plasma therapy was too weak.

Plasma donated by people who've survived Covid-19 has high levels of antibodies and is considered safe.

The proposed emergency approval was based on the history of plasma's use in treating other diseases, animal research, and a number of plasma studies, "including a federal government-financed Mayo Clinic research that's tested plasma in more than 66,000 COVID-19 patient and is the largest such study in the US".

However, top health officials including Dr Anthony Fauci, the government's top infectious disease expert have cautioned that available data wasn't strong enough to support emergency approval.

The US FDA was yet to comment on the report.

Plasma is the pale liquid that remains after red and white cells are removed from blood.

The convalescent plasma therapy has gained much traction in several countries including in India, where several lives have been saved with the therapy.

In an ongoing study of more than 300 Covid-19 patients treated with convalescent plasma therapy in the US, researchers suggest that the treatment is safe and effective.

The study, published in the American Journal of Pathology, tracked 350 severely ill Covid-19 patients admitted to the Houston Methodist's system of eight hospitals from March 28 through July 6.

"Our studies to date show the treatment is safe and, in a promising number of patients, effective," said study author James M Musser from the Houston Methodist in the US.

"While convalescent plasma therapy remains experimental and we have more research to do and data to collect, we now have more evidence than ever that this century-old plasma therapy has merit, is safe and can help reduce the death rate from this virus," Musser added.