Convalescent Plasma Therapy for COVID-19 Patients

What Is Convalescent Plasma Therapy?

Convalescent plasma therapy, a substance of human origin (derived from human donors), is used as a treatment option for life-threatening infections or diseases whose vaccines or antivirals have not yet been developed. The therapy involves using blood from a person who has recovered from the same disease or infection. The donor’s blood contains antibodies after recovery; therefore, the plasma or liquid part of the blood is extracted during plasma therapy and transfused into the affected person to help fight infectious diseases.

Convalescent plasma therapy is not a new treatment idea; it has been used to treat certain infections, such as Ebola, pandemic influenza, and Lassa. Recently, in 2020, the United States Food and Drug Administration (US FDA) authorized healthcare providers used convalescent plasma therapy for COVID-19 (2019 novel coronavirus disease) patients, and it is still considered an option for individuals with weakened immunity.

The therapy was opted for because of the lack of treatment options available for COVID-19 in 2020. Also, due to the mutations in the COVID-19 virus (SARS-CoV-2, or severe acute respiratory syndrome coronavirus 2), several treatments or medications used to prevent the fatal disease became ineffective. Therefore, to reduce the risk of serious COVID-19 illness, the FDA authorized blood plasma treatment for people who were not hospitalized but had weakened immune systems.

What Are the Criteria for Convalescent Plasma Therapy in COVID-19 Patients?

The criteria for convalescent plasma therapy in COVID-19 patients mainly depend on some specific protocols and guidelines established by the regulatory authorities.

These include the following:

• The recipient requires a positive PCR (polymerase chain reaction) test to confirm the laboratory diagnosis of COVID-19.

• It also depends on the severity of the condition. Plasma therapy is primarily indicated for patients who suffer from moderate to severe COVID-19 infection, require hospital admission, suffer from respiratory distress, and show signs of disease progression.

• Therapy is only indicated during the initial few days of the onset of symptoms. Plasma therapy is more effective when transfusions are done during the initial few days of the disease course.

• The blood plasma treatment is only done if the donor has recovered from the novel coronavirus or COVID-19 (must be asymptomatic for at least 14 days) and meets the eligibility criteria for donating plasma. The requirements also specify that the convalescent plasma obtained from the donor must have sufficient quantities of high levels of neutralizing antibodies for transfusion.

• Informed consent from the patient or their attendants is required before initiating convalescent plasma therapy in COVID-19 cases. This is done to inform them about the potential risks, benefits, and other uncertain conditions associated with plasma therapy.

• Plasma donors should also be eligible according to the standard blood donation eligibility criteria, which suggest the donor's age should be 18 to 65, their weight should be 110 pounds or 50 kilograms (kg), and they must have good health status (free from infectious or chronic diseases).

What Is the Efficacy of Convalescent Plasma Therapy in COVID-19 Patients?

The efficacy of plasma therapy in COVID-19 cases has been a topic of discussion in several research studies, and is mainly based on the following understanding:

• Some studies suggest that early administration of convalescent plasma therapy in COVID-19 patients helps reduce the risk of disease progression by almost eight percent by decreasing the patient’s viral load, thereby increasing the success rate of plasma therapy.

• Another systematic review of controlled studies established that plasma therapy potentially reduces mortality risks in patients suffering from COVID-19. The data from this study suggested that mortality can be reduced in certain cases of COVID-19, which was also the basis for an emergency authorization of convalescent plasma therapy by the FDA.

• One of the retrospective studies also revealed that the oxygen requirement and survival rate of patients suffering from life-threatening COVID-19 can be improved with plasma therapy.

What Is the Success Rate of Plasma Therapy in COVID-19 Patients?

The success rate of plasma therapy in COVID-19 patients mainly depends on the following factors:

• The time of plasma administration plays a significant role, as early transfusion (within seven to 10 days after the onset of symptoms) helps reduce viral load and improve the patient's immune response.

• The severity of the condition is such that those with severe illnesses benefit more from plasma therapy in comparison to those who suffer from mild to advanced disease progression.

• Plasma rich in high-neutralizing antibodies is more effective and shows better patient and treatment outcomes.

• In addition, the success rate of plasma therapy also depends on the presence of comorbidities. Patients who do not suffer from any other underlying condition expect COVID-19 to respond effectively to plasma therapy.

Therefore, all these factors significantly affect the recovery duration of the patient suffering from severe illness, thus leading to a quicker recovery rate for plasma therapy in COVID-19 patients.

What Are the Benefits of Convalescent Plasma Therapy for COVID-19 Patients?

• The therapy is likely to reduce severe illnesses and other complications.

• The therapy can provide antibodies for any recent variant of a specific virus.

• The therapy is generally safe and has low levels of associated risks.

• Plasma therapy can be used to treat any new illness or infection even before a new treatment, such as an antiviral drug or vaccine, is introduced.

• Plasma therapy can be given to people with weakened immunity or those who have not developed antibodies even after receiving the vaccination.

What Are the Disadvantages of Convalescent Plasma Therapy in COVID-19 Patients?

• Therapy is only effective if given during the early stages of the disease.

• Transfusion reactions may also occur, such as fever, allergies, injection site infections, and transfusion-related acute lung injury.

• Consistency and reliability of the convalescent plasma treatment due to the difference in concentration and quality of the antibodies obtained from the donors.

• A limited supply of plasma for transfusion depends on the number of patients who have recovered from COVID-19, are eligible to donate, and are willing to donate plasma for therapy.

• Challenges faced during the collection, testing, and transfusion of convalescent plasma due to the need for significant logistics and regulatory coordination.

What Is Long COVID Plasmapheresis?

Plasma exchange therapy (convalescent plasma therapy), also known as plasmapheresis, involves the removal of plasma from the donor’s blood and replacing it with albumin or saline. Therapy has been used to treat several inflammatory and immune conditions. It has recently been introduced for long-term COVID-19, a chronic condition after a SARS-CoV-2 infection that lasts three months. It is characterized by symptoms such as brain fog (thinking and concentrating problems), fatigue, weakness, tremors, headache, dizziness, pounding or rapid heartbeat, and palpitations.

Conclusion:

To conclude, convalescent plasma therapy has been promising for treating COVID-19 patients; however, the effectiveness of the treatment heavily depends on the several factors mentioned above. Therefore, for a better understanding of the treatment outcomes, further clinical research and trials are necessary to understand the significant potential of using convalescent plasma therapy in COVID-19 cases.