Delhi was among the first few states to get ICMR approval to conduct trials with plasma therapy, which is still at trial stage.
Q. What is convalescent plasma therapy?
A. The convalescent plasma therapy aims at using antibodies from the blood of a recovered Covid-19 patient to treat those critically affected by the virus. The therapy can also be used to immunize those at a high risk of contracting the virus such as health workers, families of patients and other high-risk contacts.
This therapy's concept is simple and is based on the premise that the blood of a patient who has recovered from Covid-19 contains antibodies with the specific ability of fighting novel coronavirus. The theory is that the recovered patient's antibodies, once ingested into somebody under treatment, will begin targeting and fighting the novel coronavirus in the second patient.
The convalescent plasma therapy is akin to passive immunization as, according to researchers, it is a preventive measure and not a treatment for the Covid-19 disease.
Q. How convalescent plasma therapy works?
A. The convalescent plasma therapy uses antibodies developed within an infected person while he/she is infected with the novel coronavirus. These antibodies are developed in a patient as part of the body's natural immune response to a foreign pathogen or in this case, the novel coronavirus. These antibodies are highly specific to the invading pathogen and so, work to eliminate the novel coronavirus from the patient's body.
Once the patient has recovered, they donate their blood so that their antibodies can be used to treat other patients the blood is then taken through a process to extract 'plasma', the liquid part of the blood that contains antibodies. The antibody-rich plasma, once extracted, is then ingested into the body of a patient under treatment.
Q. What is a plasma bank, why is it required?
Like in blood banks, where blood is extracted and stored for those who might be in need, the idea is to extract and store plasma from people who have recovered from Covid-19 and give it to someone suffering from the disease.
The bank is being started keeping in mind the experiences of several people who had to run pillar to post to arrange plasma for their loved ones.
Q. At what stage is the therapy in Delhi?
A. Delhi was among the first few states to get ICMR approval to conduct trials with plasma therapy, which is still at trial stage.
Once a person contracts the virus, the blood produces antibodies and certain cells ‘remember’ the antigen and produce antibodies when they come in contact with the same virus again. The plasma trial is examining if the plasma containing antibodies from recovered patients is beneficial to others as well.
Doctors in Delhi hospitals have found so far that the therapy is not as effective on critical patients, but those with moderate symptoms appear to be responding well.
Q. What are the risks involved in this?
A. Some of the risks associated with it:
1. Transfer of blood substances: As the blood transfusion takes place, there are risks that an inadvertent infection might get transferred to the patient.
2. Enhancement of infection: The therapy might fail for some patients and can result in an enhanced form of the infection.
3. Effect on immune system: The antibody administration may end up suppressing the body's natural immune response, leaving a Covid-19 patient vulnerable to subsequent re-infection.
Q. Is it the first time that Plasma Therapy is sought for a disease?
This is not the first time convalescent plasma therapy is being considered as a treatment for viral infections.
1. In 2014, the World Health Organisation (WHO) had recommended the use of convalescent plasma therapy to treat patients with the antibody-rich plasma of those who had recovered from the Ebola virus disease.
2. For the treatment of people infected with Middle East respiratory syndrome (MERS), which is also caused by a coronavirus, a protocol for use of convalescent plasma was established in 2015.
3. During the 1918 H1N1 influenza virus (Spanish flu) pandemic, the therapy was used experimentally.
4. The plasma therapy was used as a treatment during the H1N1 infection of 2009.
Q. Who can be a donor?
A. A healthy person between the age group of 18-60 years and with no comorbidities. Consent must be taken, and the patient should have recovered at least three weeks before donating and tested negative for Covid-19 twice.