Trials using the antibody-rich blood of patients cured of the coronavirus disease (COVID-19) have begun, with doctors turning to a pool of 1,600 people in India who have recovered from the infection to test their antibodies as a potential cure for those fighting the disease

Convalescent plasma therapy uses a blood component called plasma -- which contains the virus-fighting antibodies – from people who have recovered from the infection to treat those who are severely ill with COVID-19.

Apart from the Indian Council of Medical Research – India’s apex health research body – at least two hospitals have applied to test the effectiveness of the therapy in Delhi, the protocols for which have been established .

The Institute of Liver and Biliary Sciences, an autonomous Delhi government hospital, has already received approval to conduct the trials. The private Max Hospital is awaiting approval to launch the trials.

“As the same product will be tested across the centres, the approvals are being given to hospitals that conform with the ICMR protocols so that uniform and comparable data is generated from across centres,” said an official from the Central Drugs Standard Control Organisation (CDSCO), the apex drug regulator.

When the virus enters the human body, the immune system creates an antibody to fight it. This antibody remains in a person even after the virus has cleared out of their system. In the absence of other drugs, experts say that using these antibodies from recovered patients can offer a reprieve to severely ill COVID-19 patients.

“Now, there are over 1,000 people who have recovered from COVID-19 in the country and their blood plasma can be used to treat those who are critical. The antibodies from the recovered person will theoretically help the critical patients in fighting the infection. This is done for other viral illnesses as well,” said Dr SK Sarin, director of the Institute of Liver and Biliary Sciences

The therapy would be given only to patients in a critical condition -- those with a respiratory rate higher than 30 breaths per minute (the normal is 18-20 breaths per minute), have oxygen saturation of less than 90% (normal is 95 to 100%), or have infiltrates like pus in the lungs.

As for donors, only health individuals – with no comorbidities like diabetes, hypertension, or heart disease and less than 60 years of age – who have recovered from the infection would be selected.

“There are anecdotal evidences to say that COVID-19 patients on plasma therapy have recovered in other countries. However, we need to ensure that the therapy is given to people who are at high risk before they are on a ventilator. This is because the antibodies can prevent the progression of the disease by reducing the viral load, it cannot heal the lungs and the other organs. So, if a person already has lung damage and is in multi-organ failure then the therapy will not be useful,” said Dr Shobha Broor, former head of the department of microbiology at the All India Institute of Medical Sciences.

For the treatment, a plasmapheresis machine is used to derive plasma from the blood, which is then administered to the patients with severe infection. This method is, however, not new and is used for the treatment of several other diseases.

And experts feel that not giving the treatment to half the patients under randomised control trial is unethical. “Plasma therapy is already being used for three categories of ailments – one is viral infection such as hepatitis or even chicken pox that can be severe in immuno-compromised patients; two, it is done for autoimmune disorders, and three, conditions like haemophilia in which the people receive proteins other than antibodies – like factor 8 in this case – through plasma therapy,” said Dr T Jacob John, professor emeritus and former head of the department of virology at Christian Medical College, Vellore.

“When it is an already established procedure, why should it not be administered to all the patients who are very sick?. Not giving it to half the patients in need is actually an ethical problem, I feel,” he said.

In a randomised control trial, which is suggested by the ICMR, half the patients receive the plasma and the other half receive a placebo. This helps the doctors in determining whether people on therapy do better than those not on it.

A recently published report on a trial in China showed an improvement in the clinical conditions of 10 people who received the therapy. “All symptoms in the 10 patients, especially fever, cough, shortness of breath, and chest pain, disappeared or largely improved within 1 day to 3 day upon Convalescent Plasma transfusion,” the study published in PNAS Journal said.