When there is darkness all around, even a small ray of light brings a lot of hope. Similarly, when the invisible enemy in the form of CoVID-19 is presenting unprecedented challenges to the world, any kind of therapy which claims to improve the condition of CoVID-19 patients brings a ray of hope to the humanity. Plasma therapy or Convalascent Plasma (CP) transfusion is one such therapy which has been the talk of town ever since US President Trump mentioned it in his speech in late March and recently in India after Delhi CM urged recovered patients to donate plasma to save lives. But can it actually be a game changer? Let’s find out:
What is actually Plasma Therapy?
Plasma therapy or Convalascent Plasma transfusion is a form of passive immunity where readymade antibodies and proteins are provided to critically ill CoVID-19 patients by infusing plasma from recovered patients. The antibodies of the recovered person may help the patient’s immune system fight the virus.
How does it help fight CoVID-19?
Plasma mainly contains antibodies and proteins and possibly receptors like heparan which’re negatively charged that binds to many virus ligands naturally and there are reports that heparan binds to the spike protein of SARS CoV-2 (CoVID-19 virus) and inhibit SARS pseudovirus infection.
According to a peer review published in the reputed journal PNAS (Proceedings of National Agency of Sciences), USA which shows CP works really well in severe or critical CoVID-19 patients. Several parameters of the patient improved as compared to pretransfusion including increase in oxyhaemoglobin saturation (increase in blood oxygen level), increase in lymphocytes (increase in white blood cells) count and decrease in C reactive protein (indicates less inflammation), lung lesions also decreased within a week, viral load was undetectable after transfusion in most cases.
What are the limitations & Risk Factors associated with CP?
Though the plasma therapy was 1st used nearly a century ago in 1918 in case of Spanish Flu and later in case of SARS, MERS, H1N1 and Ebola, however, there is no robust evidence to support it for routine therapy as it involves a lot of risk factors and limited clinical trials have been performed so far. Till date, there have been only three published case series for convalescent plasma in the treatment of CoVID-19 with a cumulative of 19 patients. US FDA has also viewed it as an experimental and emerging therapy for the treatment of CoVID-19 due to safety and efficacy issues involved.
Risk factors/Adverse Reactions involved in CP therapy:
1. Risk of contracting non-Covid-19 infections such as hepatitis B & C, HIV etc, if the plasma isn’t properly screened.
2. Mild allergic reactions like fever, itching, rashes etc.
3. Life-threatening allergic reactions and transfusion related acute lung injury.
4. Transfusion associated circulatory overload (TACO), characteristic of respiratory distress, pulmonory oedema (excess fluids in the lungs), unanticipated cardiovascular system changes and fluid overload.
5. Also, there is always a posibility of CoVID-19 virus lurking in the plasma even after the patient has been tested negative for it.
Need of Randomised Controlled Trials
At present, it cannot be concluded that CP will work on all patients all the time or even believe that it is the only reason for their improvement given the very small number of patients involved in the 3 case studies of CP in CoVID-19 published so far and also publication bias in medicine cannot be ruled out.
So, CP treatment needs to be validated for its safety and efficacy in CoVID-19 patients for which there is a need of randomised controlled trials, where half the patients get the transfusion and the other half do not. The treatment can be considered beneficial only if patients in the first half show substantial improvement over those in the second half. For this, the Drug Controller General of India (DCGI) on April 14, cleared the protocols proposed by Indian Council of Medical Research on ‘Phase II, Open-Label, Randomised Controlled Trials’ which plans to recruit 452 patients, meeting the inclusion and exclusion criteria set for the study, involving at least 25 centres across India and is expected to be undertaken over 6 months.
Hence, given the serious uncertainties and risks involved in Plasma therapy, it can be a preferred form of treatment for CoVID-19 only after its safety and efficacy is validated by ICMR after randomised controlled trials. Further, media houses and politicians should stay away from politicising it and should rather focus on curbing CoVID-19 by means of better strategy.