NEW DELHI: A latest study in the US, the UK and Italy has shown that convalescent plasma used indiscriminately for Covid — as it has been in India — might alter the virus allowing escape mutations to dominate. An escape mutation allows SARS-COV-2 to evade antibodies specific to the spike protein which the virus uses to enter human cells.
Incidentally, ICMR director general Balaram Bhargava had warned against the random usage of unproven therapy such as convalescent plasma for Covid, saying that such practices put immune pressure on virus to mutate. To investigate the evolution of SARS-CoV-2 in the immune population, scientists co-incubated authentic virus with a highly neutralising plasma from a Covid convalescent patient.
It was found that the plasma fully neutralised the virus initially but after 80 days helped generate a variant completely resistant to plasma neutralisation. “The recent emergence in the UK and South Africa of natural variants with similar changes suggests that SARS-CoV-2 has the potential to escape an effective immune response and that vaccines and antibodies able to control emerging variants should be developed,” they noted.
Many experts have been saying that rampant use of plasma therapy without prior testing for neutralising antibodies will do more harm than good. “If plasma from someone who had a weak infection is used, the antibodies present might not be strong enough to neutralize the infection in the person the plasma is administered to,” said an ICMR scientist. “In that event the infection may not be completely eliminated but could mutate.
That mutation could possibly lead to strains of the virus that are more concerning because they are more infectious.” Others, meanwhile, pointed out that the ICMR warning should have come much earlier. “Except Dexamethasone, the only drug with proven efficacy in hospitalized and hypoxic patients with Covid, no other therapy has consistently worked in Covid-,” said S P Kalantri, a medical researcher. The list of ineffective and unproven drugs include HCQ, lopinavir-ritonavir, favipiravir, azithromycin, he said. “ICMR finally seems to have made some amends but the warning has come a bit too late.”
Cases of mutant Covid jumps to 25
New Delhi: Five new cases of the UK strain of Covid-19 have been detected in India, which takes the total number of such patients to 25. The highly infectious mutant strain, which first surfaced in the UK in September, was found to have reached India two days ago with travellers returning from the island nation. Four of the five new cases were found by National Institute of Virology, Pune and the remaining one was sequenced at CSIR-Institute of Genomics and Integrative Biology, Delhi, said the Union ministry of health and family welfare on Thursday. All 25 patients have been kept in isolation at designated health facilities. India had detected 14 new cases on Wednesday, out of which 8 were detected at the NCDC in Delhi, 4 at the National Institute of Mental Health and Neuro-Sciences Hospital in Bengaluru, and 1 each at the IGIB and the NIBG in West Bengal. On Tuesday, six people — three from Karnataka and one each from Andhra Pradesh, Telangana and UP — found with the mutant virus.