Convalescent plasma has 'limited effectiveness' in treatment, finds UK study in India

The study looked at over 400 patients who were hospitalised due to COVID-19 to find out whether the treatment healed people with moderate disease but it found that “convalescent plasma showed limited effectiveness”.

The study said in the past, convalescent plasma was used as a "passive immunisation strategy" to treat viral diseases, raising expectations that potentially it could be used to treat severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus responsible for COVIDd-19 and a disease with no proven, effective interventions"

“The ... trial was able to show a small effect on the rate at which patients were able rid themselves of the virus, but this was not enough to improve their recovery from the disease,” Simon Clarke, an expert cellular microbiology at the University of Reading said, adding, "In simple terms, there were no clinical benefits to the patients.”

It said that in the "pre-vaccine era, convalescent plasma was used to treat viral diseases such as poliomyelitis, measles, mumps, and influenza, and, more recently, influenza, Ebola virus disease, and severe acute respiratory syndrome coronavirus epidemics, with varying degrees of success."

"Evidence suggests that convalescent plasma collected from survivors of covid-19 contains receptor binding domain specific antibodies with potent antiviral activity."

"However, effective titres of antiviral neutralising antibodies, optimal timing for convalescent plasma treatment, optimal timing for plasma donation, and the severity class of patients who are likely to benefit from convalescent plasma remains unclear," it found.

The research said that convalescent plasma treatment had received regulatory approval in several countries, however, it said that due to uncertainties, it was still unclear just how much convalescent plasma was safe and effective.

"Only two randomised controlled trials on convalescent plasma use in covid-19 have been published, one from China and the other from the Netherlands," it said, adding,"both were stopped prematurely. China study because of inadequate patient enrolment, and the Dutch study because interim findings highlighted the need for a redesign of the trial."

"Neither study found a mortality benefit, and the Dutch study raised uncertainties about the pretransfusion antibody status of patients," it stated.