There is growing interest in the application of convalescent plasma therapy (CPT) to help treat Covid-19 patients.

Encouraged by studies in the US and China that show CPT may help individuals fight the new coronavirus, which causes Covid-19, India has also initiated trials to establish if the therapy can indeed help patients recover from the disease.

Plasma extracted from human blood has proved beneficial in the treatment of many infections over the past two decades, including severe acute respiratory syndrome (Sars), Middle East Respiratory Syndrome (Mers) as well as H1N1 influenza or swine flu.

It has often been described as “liquid gold” because of its yellowish colour and immunity-boosting properties.

On April 12, the Indian Council of Medical Research (ICMR), the country’s apex body to regulate biomedical research, called for applications to study the safety and efficacy of CPT in managing complications associated with Covid-19.

It has since received 99 applications from interested institutions and also begun giving permission for these trials to go ahead at different locations.

In the case of Covid-19, CPT involves drawing blood from a person who has fully recovered from the disease.

Convalescent plasma, which contains antibodies that helped the individual fight the coronavirus, is then separated from the blood using a centrifuge and administered to a Covid-19 patient to help boost his or her immunity against the disease.

The Maulana Azad Medical College (MAMC) in Delhi is one of the participating institutions in these trials. It is currently treating around 400 Covid-19 patients at the Lok Nayak Jai Prakash Narayan Hospital, which is associated with the college. Four of them received CPT this week.

Professor Suresh Kumar, the head of the Covid-19 task force at MAMC and director of its department of medicine, told The Straits Times (ST): “The results have been encouraging so far and the patients are reporting better oxygen saturation levels.

“These antibodies can be really helpful if given to the right patient at the right time. It helps them rebuild their immunity and fight the Covid-19 infection.”

But he cautioned that CPT should not be seen as a magic bullet that may help treat all Covid-19 patients.

Kumar said individuals most likely to respond well to CPT are those suffering from severe respiratory illness because of Covid-19 but without any co-morbidity such as heart or liver diseases.

Indian institutions carrying out CPT trials hope to add to the global scientific community’s understanding of how it may help treat Covid-19.

Dr Asha Kishore, the director of the Sree Chitra Tirunal Institute for Medical Sciences and Technology in Trivandrum, in the southern state of Kerala told ST: “The evidence so far [of it working] has come from a small number of patients who were on ventilators and had severe respiratory problems.

“To extrapolate that it might work as a therapy for others is predicting too much at this stage. We need to know a lot more,” she said.

The institute is one of the many that have applied to the ICMR for permission to carry out a clinical trial using CPT, she said. Its successful implementation will require donors to donate blood adequately.

“This cannot be made mandatory and will, therefore, require social workers to counsel potential donors,” she said.

Those willing to donate will also have to be transported to blood banks amid the ongoing lockdown and their samples tested for Covid-19 as well as other infections to ensure no harm is caused to recipients.

The plasma extracted has to be then sent to a hospital through a secure cold chain that maintains the temperature at minus 30C.

“These are some of the small challenges but they can be overcome,” said Dr Kishore.