Can plasma transfusion offer immunity against Covid-19?
As the world continues to grapple with the novel coronavirus amid a rising death toll, the global search for solutions continues. While the pharma industry is struggling to produce a vaccine, passive immunisation using convalescent plasma has made headlines recently.
The government has recently informed the Supreme Court that it expects over 50,000 cases of coronavirus infection by the end of April. Plasma therapy has offered a dash of hope.
“Plasma therapy is based on the collection of blood from a recovered Covid-19 individual, and transfusion of the separated plasma to a critically ill patient. Plasma is the fluid part of blood that is left when blood cells have been removed. It contains antibodies and proteins. Plasma transfusion provides a form of passive immunity to those who are critically ill,” says Dr Saqib Ansari, a Karachi-based haematologist who recently received a plasma sample donated by Yahya Jaffari, Pakistan’s Patient Zero.
A dose of plasma containing antibodies drawn from the blood of people who recovered from Covid-19 appeared to save lives, shorten the duration of symptoms, improve oxygen levels and speed up viral clearance, according to the preliminary findings of a pilot study published in the Proceedings of the National Academy of Sciences of the United States of America (PNAS). The research conducted at three hospitals in China, promised the benefits of harvesting immune antibodies from recovered people (convalescent plasma) and administering it to people battling with severe symptoms of Covid-19.
Speaking to The News on Sunday, Dr Ansari says that the United States’ Food and Drug Regulatory Authority (FDA) has approved the use of passive immunisation therapy for critically ill patients – patients with a fever of above 101 degrees Fahrenheit and those whose lungs are 50 percent affected. However, Dr Ansari cautions that as in any transfusion process, there are risks involved. “There are a few risks associated with any treatment. As it is an experimental therapy, nothing certain can be said about its outcome.”
He says that Transfusion Related Acute Lung Injury (TRALI), Transfusion Associated Circulatory Overload (TACO), allergic reactions and virus infections are risks directly associated with any plasma transmission, including transfusions related to Covid-19.
Najam Suharwardy, a journalist covering coronavirus in Karachi, believes that in a country having inadequate health facilities plasma transmission offers cautious given that a proven vaccine may be at least a year away.
“Nothing definite can be said at this stage. Only controlled clinical trials can provide clear answers on whether convalescent plasma can stop the disease or improve symptoms, and which people it could help the most.”
Despite the initial buzz on passive immunisation, there had been silence on the government front. “CM Shah said that he could not speak about potential treatments and medicines. A decision in that regard rests with the federal government,” Dr Ansari, who was present in a meeting with CM Murad Ali Shah, told TNS.
In a press release issued on April 8, the Drug Regulatory Authority of Pakistan (DRAP) gave a go-ahead to clinical trials of convalescent plasma for passive immunisation to treat coronavirus patients in response to an application filed by Dr Tahir Shamsi, chairman of the National Institute of Blood Disease and Bone Marrow Transplantation, Karachi. The application was approved a day after the meeting between health practitioners and CM Shah, in which doctors had urged the government to grant permission for passive immunisation therapy.