Rise and Fall of Plasma Therapy in Covid Treatment
Convalescent plasma therapy hardly improves recovery rate or reduce mortality, new study suggests.
Pandemics aren’t new to humanity. In the last couple of centuries, several pandemics and epidemics have stormed this planet and threatened the existence of human civilization. But humans have learned a lot from them. Like they’ve learned about convalescent plasma therapy that works effectively in the treatment of influenza, as well as pneumonia, Ebola, and plagues.
In 2020, when covid-19 broke out, very little was known about the disease. Neither medical science could offer any breakthrough cure that could contain its transmission. But physicians considered a lesson that was acquired in the past. Suddenly, convalescent plasma therapy seemed a promising therapeutic in treating the disease.
What is plasma therapy
In this method, blood plasma is collected from a survivor of a disease and is transfused in the body of a patient who is suffering from the same ailment. When a human body contracts any disease, its defense mechanism comes into play. Its immune system produces plenty of antibodies to eliminate the pathogenic particles. Depending upon the severity of the disease, the concentration of the antibody varies.
Thus, the survivor’s blood plasma contains antibodies against a pathogenic attack. After the transfusion, these antibodies try to neutralize the pathogens present in the patient’s body. The greater the count of the antibody, the more chances of recovery of the patients. This therapeutic protocol has exhibited remarkable efficacy in treating antiviral diseases.
The rise with ‘hope’
Novel coronavirus has got structural dissimilarity from its ancestor virulent species. So, medical researchers took the onus to investigate the efficiency of this antibody treatment in curing the disease. Various medical institutes and hospitals joined hands to conduct trials. Back in 2020, a cohort of researchers could demonstrate improvement in covid-19 affected patients using plasma therapy.
With preliminary results in hand, FDA issued authorization to use this therapeutic tool for emergency use. Since then, more than 100,000 people have received this treatment through randomized controlled trials (RCTs). The count has grown many times as more countries have followed the suit.
But in March 2021, National Institute of Health (NIH) halted a large RCT. Researchers had reasons to believe that convalescent plasma therapy hardly imparts any impact in curing covid-19. Studies published before the halt was responsible for influencing the decision of NIH.
A new study strengthens the pillar of that belief. The findings, published in The Lancet, suggests that this antibody therapy hardly improves the recovery rate and reduces 28-day mortality. UK-based RECOVERY Collaborative Group (RCG) also made endeavors in investigating impacts of azithromycin, hydroxychloroquine, dexamethasone before shifting their focus to antibody treatments.
Proof of inefficacy
Between May 2020 and January 2021, RCG had conducted a large-scale RCT on 11558 patients who were hospitalized after contracting the virus. The patients were randomly distributed into two groups. One group received the usual care (5763 patients) and the other group received convalescent plasma therapy along with the usual care (5795 patients).
The outcome couldn’t leave researchers astounded. 3 sets of data were collected and all pointed towards the same inference.
Firstly, they looked into the recovery prospects of the patients enrolled. 66% of patients from both groups got discharged within 28 days. The plasma group had no other effect on their body once they recuperated from the disease.
Secondly, 28-day mortality data were analyzed. Researchers discovered that the mortality rate remained the same across both groups. A staggering 24% of the patients died within 28 days of getting infected, independent of any plasma administration.
Thirdly, data pertaining to patients on ventilation. 29% of the patients, who needed ventilator support, either died or recovered from the disease. The percentage remains identical across the groups that participated.
The fall with ‘fact’
In a nutshell, the plasma group had no advantage (or, disadvantage) over the usual care group. So, these outcomes led researchers to infer that convalescent plasma therapy is an inefficacious therapeutic tool for covid-19.
The reason for its futility in curing covid-19 remains elusive. Previously, researchers hypothesized that the presence of antibodies in the recipient’s body may not let the foreign antibodies work. Thus, no effect could be observed. But RCG-led investigation revealed that patients, with scanty antibody concentration, still received no observable benefits after receiving convalescent plasma.
As new evidence surfaces, apex medical bodies of various countries have started to take action. Indian top medical body, ICMR, has dropped convalescent plasma therapy from its covid-19 treatment guidelines. Even the US has stopped conducting new RCTs albeit FDA keeps reauthorizing the therapy for emergency usage.
This research only encompasses patients who had to be admitted to the hospital. That means convalescent plasma therapy fails to improve conditions of severely ill patients. But the researchers couldn’t confidently conclude if mild-to-moderate conditions could receive benefits from this therapy.
It remains to be seen what unfolds next as medical science discovers more facts and innovate treatments to eradicate this menace in the foreseeable future.