From UPSC perspective, the following things are important :
Prelims level : Plasma therapy
Mains level : Efficacy of the plasma therapy
Recently published findings on convalescent plasma therapy on Covid-19 patients have triggered a debate over its efficacy.
- Plasma is the liquid part of the blood. Convalescent plasma, extracted from the blood of patients recovering from an infection, is a source of antibodies against the infection.
- The therapy involves using their plasma to help others recover. For Covid-19, this has been one of the treatment options.
- The donor would have to be a documented case of Covid-19 and healthy for 28 days since the last symptoms.
How is it done?
- The process to infuse plasma in a patient can be completed quickly.
- It only requires standard blood collection practices, and extraction of plasma.
- If whole blood is donated (350-450 ml), a blood fractionation process is used to separate the plasma.
- Otherwise, a special machine called aphaeresis machine can be used to extract the plasma directly from the donor.
- While blood is indeed extracted from the donor, the aphaeresis machine separates and extracts the plasma using a plasma kit, and the remaining blood components are returned into the donor’s body.
- WHO guidelines in 2014 mandate a donor’s permission before extracting plasma.
- Plasma from only recovered patients must be taken, and donation must be done from people not infected with HIV, hepatitis, syphilis, or any infectious disease.
- If whole blood is collected, the plasma is separated by sedimentation or centrifugation, then injected in the patient.
- If plasma needs to be collected again from the same person, it must be done after 12 weeks of the first donation for males and 16 weeks for females, the WHO guidelines state.
What has happened to spark the debate?
- An ICMR study has found convalescent plasma was not associated with a reduction in progression to severe Covid-19 or all-cause mortality.
- While the use of this therapy seemed to improve the resolution of shortness of breath and fatigue in patients with moderate Covid-19, this did not translate into a reduction in 28-day mortality or progression to severe disease.
- Progression to severe disease or death at 28 days after enrolment occurred in 44 (19%) of the participants in the intervention arm as compared to 41 (18%) in the control arm.
What happens if ICMR does remove the therapy from its guidelines?
- The authorisation of convalescent plasma as a treatment for Covid-19 in India has led to questionable practices such as calls for donors on social media, and the sale of convalescent plasma on the black market.
- The ICMR has been cautious because of the trial findings.
- However, those guidelines are not necessarily binding and it is too early to dismiss convalescent plasma therapy. But there are other issues.
- The therapy involves resource-intensive processes such as plasmapheresis, plasma storage, and measurement of neutralizing antibodies.
- This is a new virus, and around the world, the evidence is still emerging on the best therapeutic options.
- Covid care is individualized care. Use of the right medication on the right patient does work.
- Some of the therapies can be continued on compassionate grounds.
- However, the potential harms of the non-immune components of convalescent plasma should be rigorously investigated.
- Only donor plasma with detectable titers of neutralizing antibodies should be given to trial participants, to ensure that the potential for benefit exists for all intervention arm patients.
Try this question:
Q.What is convalescent plasma therapy? Discuss its efficacy and limitations for COVID-19 treatment.