Plasma therapy started by Sawai Man Singh (SMS) medical college in Rajasthan to treat serious coronavirus-infected patients has delivered "promising" results so far, a top doctor at the facility said.
The therapy has been successfully given to three patients and two more are likely to be administered the same soon. The team of doctors is encouraged with the results, Principal and Controller of SMS medical college Dr Sudhir Bhandari said.
Bhandari, who is heading the team which is performing Covid-19 plasma transfusion since last week at the hospital, said three successful therapies have been conducted and the results were "promising".
"So far, we have conducted three successful Covid-19 plasma therapies and all the three patients are showing improvement in their clinical state, oxygen saturation and D-dimer levels," he said.
"This has given a ray of hope," he added.
A D-dimer test is a blood test that can be used to help rule out the presence of a serious blood clot.
Bhandari said the convalescent plasma therapy is being conducted as per the protocol of the Indian Council of Medical Research (ICMR) and with the permission of the Drug Controller General of India (DCGI).
The therapy aims at transfusing plasma (component of blood) containing antibodies donated by a recovered Covid-19 patient to the serious coronavirus patients harbouring an active infection.
The patients are given the dose of 200 ml of plasma on two consecutive days, he said.
Elaborating on the therapy, Bhandari said the donors of plasma are the Covid-19 patients who have recovered after 21 to 28 days of their illness.
Repeat testing is done on recovered patients and when found negative, they are found to be suitable donors. Antibody detection rapid test is also done that shows whether protective antibodies have formed in the recovered patients, he said.
"After that, their plasma is obtained for donation and infused into blood group of matched recipients, who are suffering from active corona infection," he said.
Bhandari said convalescent plasma or immune globulins has been used as an adjunct therapy to improve the survival rate of Covid-19 patients, whose condition continue to deteriorate despite treatment.
He said several studies have shown a shorter hospital stay and lower mortality in patients who are treated with convalescent plasma.
"One possible explanation for the efficacy of convalescent plasma therapy is that the antibodies from convalescent plasma might suppress viremia (the presence of viruses in the blood) by mopping up the inciting viral antigens," he said.
Bhandari said standard treatment protocols are being followed in addition to standard medical supportive treatment while treating the Covid-19 patients.
"We used hydroxychloroquine and antiviral Lopinavir 400 mg and Ritonavir 100 mg for the first time in Covid positive patients which ignited thought process and many research trials for treatment of Covid-19 cases."
Convalescent plasma has previously been used against viral illnesses such as rabies, hepatitis B, polio, measles, influenza and Ebola. It was also used in the outbreaks of MERS and SARS-1, where faster viral clearance following convalescent plasma therapy was observed, he said.
Bhandari said plasma therapy is a form of passive immunisation, unlike a vaccine, which produces active immunity.