Convalescent plasma therapy – Is it treatment for COVID - 19?

Convalescent plasma therapy – Is it treatment for COVID - 19?

The world seems to be vulnerable in the face of the COVID – 19 pandemics, with over 4.1 million cases already and over 282,000 deaths due to its infection. Scientists are working diligently to develop the preventable vaccine and to prove the efficacy of many currently available drugs including antivirals, protease inhibitors, nucleotide analog, and interleukin inhibitors all around the globe. Convalescent plasma is another therapeutic strategy that is under investigation to treat severe patients.

Convalescent plasma therapy uses antibodies found in the blood of people who have recovered from infection (or convalesced), to treat infected patients. In this, blood is drawn from a person who has recovered from the disease, and the serum is separated and screened for virus-neutralizing antibodies.

Back then in the late 1800s, the convalescent blood product was used to treat infectious disease, firstly in treating diphtheria. The therapeutic regimen was studied during the Spanish influenza pandemic of 1918-1920. By the 1930s it was used widely to treat different infectious diseases, such as scarlet fever and pneumococcal pneumonia. However, with the development of antimicrobial, its use declined by the middle of the 20th century. Whenever new epidemics or pandemics emerges, the use of passive antibody therapy has been renewed e.g., in previous corona virus outbreaks—SARS in 2002–04 and Middle East respiratory syndrome in 2012. For other infectious diseases, the positive results guided WHO to publish guidance on the use of the treatment for Ebola virus disease, and treatment benefits have shown lower mortality in patients with severe pandemic influenza A(H1N1) 2009 virus (H1N1 2009). However, definitive clinical evidence showing the efficacy of convalescent plasma is scarce.

Recently, two small studies were done in China, a case series of five critical patients receiving mechanical ventilation and a pilot study done in ten severe COVID-19 patients. The convalescent plasma therapy showed to be safe and improvement in clinical outcome, including fever, Sequential Organ Failure Assessment score, and respiratory symptoms, in some cases within 1–3 days of treatment. The US Food and Drug Administration has approved the use of this therapy under compassionate use rules. Other trials are also planned or underway in China, Colombia, Iran, Mexico, and the Netherlands. However, it's not easy to find enough people who are eligible to donate. It is expensive and cannot be done on a large scale.

The success of convalescent plasma therapy depends on the donation of plasma by the people who have recovered from COVID-19 and have high concentrations of anti-SARS-CoV-2 antibodies. Survivors will be able to donate only twice, 400 ml each time, possibly saving 2-3 lives. The donor and the patient must be of compatible blood types, and the plasma is then tested for multiple diseases, including COVID-19, Hepatitis, and HIV. Then, again tested to make sure it has enough antibodies to effectively treat or prevent COVID-19. This type of immunity provides immediate protection against the antigen but is not long-lasting.

In Nepal, the Ministry of Health and Population is also planning to use the plasma therapy and has directed a team of experts to prepare the directives to support plasma therapy for the treatment of corona virus-infected patients.

The main challenges for the health care provider might be finding eligible donors and implementing testing to confirm adequate antibody levels in plasma. Likewise, blood transfusion reactions, another potential complication is the transmission of unknown pathogens and infection risk to laboratory personnel processing the plasma.

References

Chen, L., Xiong, J., Bao, L., & Shi, Y. (2020). Convalescent plasma as a potential therapy for COVID-19. The Lancet.

Editorial. (2020, May 01). The resurgence of convalescent plasma therapy. The Lancet Haematology.

Kai Duan, B. L. (2020). Effectiveness of convalescent plasma therapy in sever COVID-19 patients. Proceedings of the National Academy of Science of the United States of America. USA.

Marano, G., Vaglio, S., Pupella, S., Facco, G., Catalano, L., Liumbruno, G., & Grazzini, G. (2016). Convalescent plasma: new evidence for an old therapeutic tool? Blood Transfusion.

Shah, D. R. (2020, April 09). Plasma therapy: New hope for COVID 19. The Himalayan Times.

 

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