Convalescent plasma therapy is an experimental procedure and uses antibodies from the blood of cured patients to treat severely-ill COVID-19 patients.
In India, the Delhi and Kerala governments have received approval to use convalescent plasma therapy to treat severely-ill patients on a trial basis.
In Delhi, approval was received by the Institute of Liver and Biliary Sciences while Sree Chitra Tirunal Institute for Medical Sciences and Technology got the approval in Kerala.
How does it work?
People who survive an infectious disease like COVID-19 are generally left with blood containing antibodies, or proteins made by the body’s immune system to fight off a virus. The blood component that carries the antibodies can be collected and given to newly infected patients. This is known as “convalescent plasma.”
Plasma from a single donor can be used to treat three or four patients, Reuters reports.
The donors must have been diagnosed with COVID-19 and need to wait a defined period of time after they test negative for the disease before donating plasma.
Donors must also be healthy enough to meet the other requirements for blood donation — plus get an additional test to see if their antibody level is high enough.
“You don’t want to take plasma from someone who had a mediocre immune response. That wouldn’t be helpful,” said Dr. Julie Ledgerwood of US’ National Institutes of Health told the Associated Press.
Dr Sarin of Delhi’s Institute of Liver and Biliary Sciences told the Hindustan Times, “India doesn’t manufacture antibody testing kits. This makes it impossible to measure the antibody levels of a Covid-19 patient who has recovered. We’re choosing only those healthy patients who have recovered, as they are likely to have a good immunity response,” said Dr Sarin.
The donors should also not have comorbidities like diabetes, hypertension, a heart condition or be below the age of 60.
Dr. Jeffrey Henderson of Washington University School of Medicine told AP that the plasma therapy is “a stopgap measure that we can put into place quickly”.
Henderson said it’s “not a cure per se, but rather it is a way to reduce the severity of illness”.
In an article for The Conversation, virologist Anne Sheehy explained: “For instance, each SARS-CoV-2 virus (which causes the Covid-19 disease) is covered by distinctive spike proteins that it uses like keys to unlock the doors to the cells it infects. By targeting these spikes – imagine covering the grooves of a key with tape – antibodies can make it nearly impossible for the virus to break in to human cells. Scientists call these kind of antibodies “NAbs” because they neutralise the virus before it can gain entry.”
Trials across the world
Indian Council of Medical Research said that the therapy has been successful in limited clinical trials in some countries on patients who were in severe condition or on ventilator support.
Among the countries conducting trials are the US, the UK, Italy, Iran, Mexico, Colombia and China.
In the United States, the Food and Drug Administration Friday announced a national study, led by the Mayo Clinic, to help hospitals offer the experimental plasma therapy and see how they fare. The American Red Cross will help collect and distribute the plasma, the Associated Press reported.
In China, a report published by scientists working in Shenzhen, suggested that plasma was successful in treating five critically ill patients.
Risks of the plasma therapy can include infusion site reactions or other rare, allergic reactions.
India’s trials
ICMR, the medical body at the forefront of India’s coronavirus fight, does not recommend this as a treatment option outside of clinical trials.
As per its guidelines, hospitals and institutions planning to provide this treatment can do so in a clinical trial with protocols which are cleared by the Institutional Ethics Committee with approval from the Drug Controller General of India (DCGI).
Last week, ICMR sought participation in a randomised controlled study to assess the safety and efficacy of convalescent plasma to limit complications associated with COVID-19. It also sought participation in the study on therapeutic plasma exchange in improving the clinical status of COVID-19 patients.
(With inputs from Reuters and the Associated Press)