Plasma Therapy: Hope for Covid-19 Patients

The pandemic of Covid-19 has badly affected the world. Till date 8,347,893 people have caught the disease and 448,858 have lost their lives. Even after extreme loss of lives and economy around the globe, unfortunately, any cure has not been identified till now. Several medicines are under consideration and are being tested by medical professionals, but no any specific medicine or vaccine has been identified. In this painful and depressing situation plasma therapy has proved to be a breeze of fresh air.

Plasma therapy is nowadays talk of the town and there are so many questions and discussions about it?

What is plasma?

What is convalescent plasma therapy?

How plasma is donated?

Who can donate plasma?

Which Covid-19 patients can be treated using plasma?

How successful is it?

And the list goes on ...

In this article all these questions are answered.

What is Plasma?

The liquid part of blood is called Plasma and is composed of water, enzymes, salts, antibodies and blood clotting factors. It is yellowish in color due to the presence of bilirubin. It has major role in blood clotting, immune response and in maintaining the osmotic balance of the body. It shares the largest part of blood i.e., 55%.

What is Convalescent Plasma Therapy?

Convalescent plasma therapy (CP) is a classic adaptive immunotherapeutic method and is being used since 18^th century. The physician opts for CP when no other treatment works for the patient in case of infectious diseases. Antibodies are taken from the blood of a person who has already been recovered from that virus and are transfused into a severely sick person who is also a victim of the same virus but is unable to combat and to recover. These external antibodies then help the patient to kick-start his own immune response to encounter the infection and leads to the recovery.  

It has been used for treatment of several viral diseases such as, SARS-Cov-1¹, Ebola outbreak², MERS³, Spanish flu, H1N1 and many more. This classical method of passive immunization has come into the limelight for its significance in Covid-19 treatment. First it was practiced in China, the epicenter of Covid-19 and gave successful results. Then it is being practiced in many countries after the approval by FDA. It has also been approved by Drug Regulatory Authority of Pakistan (DRAP) as a treatment for Covid-19.

Plasma Donation

An individual cannot donate plasma only as it is misunderstood among the masses. Plasma is collected from a donor by a process known as “Apheresis”. It is quite similar to blood donation. The whole blood is taken from the donor following standard protocol and then the plasma is separated from the whole blood by a process called “Plasmapheresis” and then the RBCs and remaining cellular components are returned into the donor’s body along with sterile saline. This process may take 2-3 hours which is slightly longer than whole blood donation.

Who can donate plasma?

The healthy persons who have been completely recovered from the infection and have got their PCR negative can donate plasma after two weeks of their recovery. Only same blood group plasma can be injected into a patient. As it is also a misconception that since the inherited antigens are present on RBCs, so the difference of blood group does not make an effect. But it is completely wrong and can lead to fatal hemolytic transfusion reactions. The donor must be a healthy individual and must not carry any blood disease or infection. Therefore, a series of blood tests for eliminating any possibility of HBV, HCV, HIV and syphilis are conducted before donation. The presence of antibody is detected mostly using ELISA. For plasma donation antibody titers should be minimum 1:1160 and  the donor must also be IgG positive.

Which Covid-19 patients can be treated using plasma?

Those Covid patients which are having serious difficulty in breathing and whose oxygen saturation has reduced to 93% or lower and having 30% lung infiltration would be considered for plasma transfusion.

How successful is it?

Although the efficacy of plasma therapy has been reported from a number of trials carried out on other viral and infectious diseases and recent trials on Covid-19 patients are also supporting its effectiveness. Successful results have been achieved in China⁴ as 4 out of 5 patients showed potential recovery after administration of convalescent plasma and 3 of them were weaned from ventilator after 2 weeks of the treatment. Favorable outcomes have also been observed in Korea⁵, United States⁶ and many other countries including Italy, Spain, India and Pakistan as well. According to a report 130 out of 150 ventilator bound patients were fully recovered and discharged from the hospitals after receiving CP, which is a very hopeful and pleasant scenario.

Risks associated with Plasma Therapy

The plasma transfusion is safe for most of the patients, but some serious side-effects have also been observed such as;

·         Allergic and febrile reactions

·         Bronchospasm

·         Life-threatening transfusion reactions

·         Transfusion-related acute lung injury

·         Transmissions of infections such as, HIV

·         RBC allo-immunization⁷

Despite of all these reported positive outcomes, such cases have also been observed who could not recover from Covid-19 even after plasma transfusion. Hence to ascertain its efficacy much more trials are required. We reiterate convalescent plasma therapy is under trial and neither always helpful nor recommended continually and is being employed only as the last resort and used temporarily as a “silver bullet” to decrease the mortality rate of corona virus.

Last but not least it is not that miracle cure for which the whole world was waiting, there is still a dire need of a vaccine or a specific drug for treatment of SARS Covid-19. We hope that soon we will be successful in developing a specific treatment for the disease and the entire world would get freedom from this placidity and economic paralysis.

References

1.  Cheng, Y., Wong, R., Soo, Y. O. Y., Wong, W. S., Lee, C. K., Ng, M. H. L., ... & Cheng, G. (2005). Use of convalescent plasma therapy in SARS patients in Hong Kong. European Journal of Clinical Microbiology and Infectious Diseases, 24(1), 44-46.
2. Kraft, C. S., Hewlett, A. L., Koepsell, S., Winkler, A. M., Kratochvil, C. J., Larson, L., ... & Marconi, V. C. (2015). The use of TKM-100802 and convalescent plasma in 2 patients with Ebola virus disease in the United States. Clinical Infectious Diseases, 61(4), 496-502.
3.  Arabi, Y., Balkhy, H., Hajeer, A. H., Bouchama, A., Hayden, F. G., Al-Omari, A., ... & Merson, L. (2015). Feasibility, safety, clinical, and laboratory effects of convalescent plasma therapy for patients with Middle East respiratory syndrome coronavirus infection: a study protocol. Springerplus, 4(1), 1-8.
4. Shen, C., Wang, Z., Zhao, F., Yang, Y., Li, J., Yuan, J., ... & Wei, J. (2020). Treatment of 5 critically ill patients with COVID-19 with convalescent plasma. Jama, 323(16), 1582-1589.
5.  Ahn, J. Y., Sohn, Y., Lee, S. H., Cho, Y., Hyun, J. H., Baek, Y. J., ... & Roh, J. (2020). Use of convalescent plasma therapy in two COVID-19 patients with acute respiratory distress syndrome in Korea. Journal of Korean medical science, 35(14).
6. Brown, B. L., & McCullough, J. (2020). Treatment for emerging viruses: convalescent plasma and COVID-19. Transfusion and Apheresis Science, 102790.
7. Pandey, S., & Vyas, G. N. (2012). Adverse effects of plasma transfusion. Transfusion, 52, 65S-79S.

By: Mehwish Hamid