After finding it non-beneficial in reducing the progression of severe Covid-19, the government revised the clinical guidance for COVID-19 treatment, dropping the off-label use of convalescent plasma on Monday. The decision was taken after a meeting of the ICMR-National Task Force for COVID-19 held last week. All members of the panel favoured the removal of convalescent plasma from the guidelines, citing its "ineffectiveness and inappropriate use" in many cases.
An Indian Council of Medical Research (ICMR) official said the task force "revised" the Clinical Guidance for Management of Adult COVID-19 Patients and "dropped convalescent plasma (off label)", reported PTI. As per the previous guidelines, doctors could use plasma therapy on patients having moderate symptoms in seven days of onset of the symptoms, and if there is the availability of a high titre donor plasma.
Some clinicians and scientists, including vaccinologist Gagandeep Kang, surgeon Pramesh CS and others, have written Principal Scientific Adviser K Vijay Raghavan, advising against the "irrational and non-scientific use" of convalescent plasma for COVID-19.
The letter, also marked to ICMR chief Balram Bhargava and AIIMS Director Randeep Guleria, said the current guidelines on plasma therapy are not based on existing evidence and pointed out some very early evidence that indicates a possible association between the emergence of variants with lower susceptibility to neutralising antibodies in immunosuppressed people given plasma therapy.
These scientists and clinicians also warned that irrational use of plasma therapy could lead to the development of more virulent strains, fuelling the pandemic. "This has stemmed from guidelines issued by government agencies, and we request your urgent intervention to address the issue which can prevent harassment of COVID-19 patients, their families, their clinicians and COVID-19 survivors," said the letter.
What is convalescent-plasma therapy?
When a pathogen like a novel coronavirus infects, our immune systems produce antibodies. Like the police dogs, the antibodies span out to identify and mark the invading virus. White blood cells attach to the identified intruders, and the body gets rid of the infection. The therapy, like blood transfusion, harvests the antibody from a recovered patient and ingest it into a sick person. Helped by the antibody, the immune system mounts robust combat on the virus. However, experts have said that as per the latest evidence, convalescent plasma offers no such benefit for the treatment of COVID-19 even as it's being widely used across hospitals in India.
What are antibodies?
Antibodies are one of the front-line immune responses to an infection by a microbe. They are a particular type of proteins secreted by immune cells called B lymphocytes when they encounter an invader, such as a novel coronavirus. The immune system designs antibodies that are highly specific to each invading pathogen. A particular antibody and its partner virus are made for each other.
Challenges in plasma therapy
This therapy is not simple to harness, primarily due to the difficulty of obtaining significant amounts of plasma from survivors. In diseases like COVID-19, where most of the victims are aged, suffering from other medical conditions such as hypertension, diabetes, and so on, not all recovered patients can volunteer to donate blood.