How Is Plasma Donation Different From Blood Donation?
Can plasma therapy help us in the fight against COVID-19?
In the fight against COVID- 19, in the absence of vaccines and tried-and-tested medicines, one of the medical techniques increasingly being used is ‘Convalescent Plasma Therapy’. After the United Kingdom, China, South Korea, Canada, and the United States tried the technique, India has dashed ahead and established its first ‘Plasma Bank’ in the capital city, New Delhi, specifically for patients afflicted by the novel coronavirus.
What is plasma? Where it would be sourced from?
Human blood is composed of several constituents, including the RBCs (Red Blood Cells), WBC (White Blood Cells), platelets, and plasma. Plasma is the liquid component of blood, 55% by volume which holds the blood cells. Furthermore, plasma is 92- 95% water along with proteins, electrolytes, glucose, oxygen, carbon dioxide and other substances.
Plasma also serves another major function in human existence. Whenever a patient recovers from an infectious disease, the body develops antibodies. These antibodies provide immunity to that disease in the future, and this is the keystone in the concept of vaccination.
In convalescent plasma therapy, the plasma from a recovered patient’s blood (rich in antibodies) is transfused to an actively-ill patient to provide the recipient with immunity against the disease.
The immunity generated using this therapy lasts for a few days, while the patient is critically ill and it helps them fight the illness. This technique has been deemed effective against diseases of infectious origin such as SARS, MERS, H1N1 and a few rare diseases such as Haemophilia A and Von Willebrand disease.
We have yet to ascertain the effectiveness against COVID- 19, as the trials are still in progress.
In plasma therapy, although ‘whole blood’ would be extracted from the patient who has recovered, it is not the same as ‘blood donation’. The two essential differences being:
- In plasma donation, only plasma is retained from the blood and all the other components are returned to the body. Unlike the RBCs which have a short shelf life of about 6 weeks, plasma can be frozen for almost up to a year.
- Unlike blood, which can be donated once in three months in normal circumstances, about 500 ml of plasma can be donated every 15 days by a recovered patient, as it regenerates in just a few hours.
Plasma is listed in the WHO Model list of Essential Medicines. Compared to other blood groups, ‘AB’ is the preferred blood type for plasma donation, and considered a ‘universal donor’ for plasma.
Although deemed necessary in present circumstances, there are potential risks involved in the plasma transfusion. For instance, in the case of Dengue, there is a lack of evidence-based guidelines and treatment could worsen the situation as it leads to replication of the virus. This means platelets are preferred to be transfused instead of other blood components. In this case, there is a lack of definitive studies demonstrating the effectiveness of plasma therapy. There is also the added risk of transfer of unknown pathogens and transfusion-associated reactions.
Challenges in Plasma Therapy
With the establishment of plasma bank in New Delhi, individual medical facilities having started conducting the therapy. Certain implementation challenges remain particularly in India:
- There is a compelling need for public awareness regarding ‘plasma donation’, especially among the patients who have recovered from the disease.
- The red-tapism, bureaucratic inertia and regulatory health protocols in the approval of licenses for conduction of plasma therapy in the hospitals (as ‘Health’ forms a part of ‘State List’) means the authority to make rules and regulations for the sector lie with individual states, and not entirely with the Government of India.
- The training required with regard to novelty of the procedure and unfamiliarity with the technique is bound to take its fair share of time for trickling down to the patients across India, keeping in view the rural-urban divide in medical infrastructure.
- For a socially and economically diverse population of 1.3 Billion and counting, accessibility, and affordability to advanced medical facilities remains an integral challenge.
“Science knows no country, because knowledge belongs to humanity, and is the torch which illuminates the world” ~ Louis Pasteur
