The therapy involves taking antibodies from the blood of a person who has recovered from COVID-19 and transfusing those antibodies into an active coronavirus patient to help kickstart the immune system to fight the infection.
The Health Ministry last week warned against its use, saying that the plasma therapy for treatment of coronavirus patients is at an experimental stage and has the potential to cause life-threatening complications.
However, some state governments, including Rajasthan, Punjab, Maharashtra and Delhi have shown keenness for plasma therapy treatment, and the Centre has permitted few states to perform plasma therapy on a limited number of COVID-19 patients.
Top medical experts feel it should not be looked upon as something that could make a "huge difference" in the treatment of COVID-19 and only randomised controlled trials can prove its efficacy as an important treatment strategy.
Director of AIIMS, Delhi, Randeep Guleria said there have been very few convalescent plasma therapy trials as far as COVID-19 is concerned, and only in very few patients it has shown some benefit.
"It is just one part of the treatment strategy. It helps improve the person's own immunity by giving what we call passive immunity because the antibodies in the plasma enter the blood and try to help fight the virus in the afflicted individual. It is not something which will dramatically make a difference," Guleria told PTI.
There is no study to suggest that "it is a magic bullet" or it will make a dramatic difference, but it is part of the armamentarium of treatment that physicians have along with other drugs, the senior pulmonologist said.
ICMR has already called for a proposal and a large number of institutes have enrolled for the convalescent plasma therapy trials, he said.
"Important issue to remember is that not everyone's plasma can be given, you also have to test the blood ----whether it is safe and also has enough antibodies. So, you have to have an antibody testing mechanism which is being done by NIV (National Institute of Virology), Pune, to show that the plasma you are giving has enough antibodies" Guleria said.
Research should be done on a multi-pronged treatment strategy and should not be focused on only one strategy, the AIIMS Director said.
"You will need to give it to a large number of individuals, more than 200 or 300 people and then analyse the data...We should go ahead in research mode giving it to more people and do a proper well conducted study so as to know one way or the other," Guleria said.
Dr Vivek Nangia, Director Pulmonology, MICU and Sleep Disorders, Fortis Hospital, Vasant Kunj, said the therapy is only in the experimental stage, but it is promising as there is a clinical knowledge involved, and also some experiments and past experience behind it having been used for SARS and H1N1 epidemics in a limited manner.
"Dire circumstances require desperate measures, you need to have an out of the box thinking and this is one of those measures, when nothing else is working you want to try this, there is no harm. It has its pros and cons," he told PTI.
Backing Guleria, Nangia also said, "larger randomized placebo-controlled trials are very essential only then we can make it a standard of therapy."
These expert views come amid lack of definitive evidence in favour of or against the use of the convalescent plasma therapy.
As per reports, a patient who was administered plasma therapy for the first time at a private hospital here was discharged last week after being cured, while the first person to undergo plasma therapy in Maharashtra had died in Mumbai's Lilavati Hospital.
Chief minister Arvind Kejriwal had said last week that the Delhi government will not stop clinical trials of plasma therapy to treat severally-ill COVID-19 patients as its initial results are good.
Rajasthan Chief Minister Ashok Gehlot on Sunday said that with the ICMR nod, SMS hospital in Jaipur will start convalescent plasma therapy on COVID-19 patients from Monday, while Maharashtra, which had started the trials last month after a nod from the ICMR, is considering to continue with it despite the Union health ministry warning.
Professor Rajesh Malhotra, Chief Trauma Centre AIIMS, said as of now, there is no concrete evidence of convalescent plasma therapy's usefulness.
"It essentially relies on the assumption that the body fires up its resistance in the form of chemicals called antibodies to fight the infection and those who have recovered have sufficient numbers in their convalescent plasma to fight the infection," Malhotra said.
However, the degree of antibody response that a person throws and the timing are variables, making it difficult to have a predictable standard protocol, he said.
It is too early to say if plasma treatment is the only wayand it has its own risks also, the AIIMS professor said, adding that at present it is at best an experimental therapy and definitive answers cannot be obtained without large-scale trials.
Dr Pankaj Kumar, Head of Critical Care Unit Fortis Hospital, Shalimar Bagh, echoed similar views, saying trials till now are too small to clear doubts about the therapy and large-scale trials should be done.
"Theoretically speaking it should be helpful because we are taking the antibodies from a person who has had the infection. But it is still experimental... we have to weigh the risks and benefits," he told PTI.
Dr Atul Kakar, Vice-Chairman, Department of Medicine, Sir Ganga Ram Hospital, said it is very important to pick the right patient for being the donor as he has to have a very severe infection so that the antibodies are quite high and should be free from other viruses.