Administering convalescent plasma from recovered COVID-19 patients can dramatically improve the likelihood of survival among blood cancer patients hospitalised with the deadly virus, according to a study.

The study led by researchers from the Washington University in the US indicates a 48 per cent reduced risk of death for COVID patients who had blood cancer and had received convalescent plasma compared to similar patients who did not receive this treatment. The survival benefit with convalescent plasma was even greater in patients who were admitted to the intensive care unit (60 per cent reduced risk of death) and those who needed mechanical ventilation (68 per cent reduced mortality).

"These results suggest that convalescent plasma may not only help COVID-19 patients with blood cancers whose immune systems are compromised, it may also help patients with other illnesses who have weakened antibody responses to this virus or to the vaccines", said Jeffrey P. Henderson, Associate Professor of medicine and of molecular microbiology at the University's School of Medicine in St. Louis. "The study also emphasises the value of an antibody therapy such as convalescent plasma as a virus-directed treatment option for hospitalised COVID-19 patients", Henderson added. The findings are published in the journal JAMA Oncology.

The therapy involves transfusing plasma the pale yellow liquid in the blood that is rich in antibodies -- from people who have recovered from COVID-19 into patients who have leukaemia, lymphoma or other blood cancers and are hospitalised with the viral infection. The goal is to accelerate their disease-fighting response. Cancer patients may be at a higher risk of death related to COVID-19 because of their weakened immune systems.

The team studied 143 patients who received convalescent plasma, and 823 who did not. Of the 338 patients admitted to ICUs because of severe COVID-19 symptoms, such as difficulty breathing or cardiac distress, those who received the treatment were more than twice as likely to survive. In March 2020, the US Food and Drug Administration approved convalescent plasma therapy to COVID patients if requested by their physicians. Last month the Indian Council of Medical Research dropped the plasma therapy as COVID-19 treatment, citing no significant benefit.