Fresh plasma from Covid-19 convalescents.
Photographer: Omar Marques / Getty Images
Photographer: Omar Marques / Getty Images
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British doctors who spent 102 days treating a cancer survivor for Covid-19 documented how the virus moved after the man was treated with convalescent plasma.
The case study suggests that the use of donated blood plasma from Covid-19 survivors could have put enough pressure on the virus to force it to evolve. The result: lower susceptibility to antibodies in the immune system that normally fight infections, according to a report published Friday in the journal Nature.
While convalescent plasma did not appear to harm the patient, it did not provide any clear benefit, the lead author said. Ravindra Gupta, Professor of Clinical Microbiology at the Cambridge Institute for Therapeutic Immunology and Infectious Diseases. It should be used with caution in people with chronic immune disorders, he said, preferably in clinical trials or in carefully controlled settings.
The report also suggests that many mutations may occur among patients who have compromised both the immune system and chronic infections.
“When the virus has a chance to stay in one person for a long time and reproduce for weeks and months, it learns how to fight the immune system,” Gupta said. It’s all about “pressure on the virus.”
The patient did not develop the exact variant that has now become the dominant form of the virus circulating in the UK, the report says, but had certain elements in common. “It just illustrates that someone like him probably has zero patience,” Gupta said.
Slow mutations
In general, Covid-19 moves relatively slowly. That’s because it’s a fast-moving virus, giving it little time to evolve. In this case, however, the patient and his doctors fought the virus for 102 days from the time he was diagnosed until he died, Gupta said.
The patient was diagnosed with Covid-19 at a local hospital in the spring of 2020, when the first wave of the virus reached crisis levels in the UK. He was later taken to Cambridge University Hospitals for more intensive care.
The team there tested him twice a week to see if the treatments he was receiving included Gilead Sciences Inc. Remittance it was reducing its viral load. They weren’t.
Genetic profiling
At the same time, the samples were sent for genetic profiling. This led to a snapshot of the virus moving over time, allowing researchers to find out where, how and when the pathogen changed as the months evolved.
There were few changes in the virus after receiving two remdesivir treatments in the first two months, according to the researchers. However, after convalescence plasma administration, there were large, dynamic changes in the virus population, including in the key protein, which the virus uses to block and infect healthy cells.
The variants then showed evidence of reduced susceptibility to neutralizing antibodies that normally control the virus.
Great study
The case study comes almost a month later A large UK national study examining convalescent plasma as therapy was completed after it was found that the treatment of US President Donald Trump was not working.
Research at Oxford University has been part of a clinical trial called Recovery, which investigates various Covid-19 treatments. The other arms of the study are ongoing.
The results come after more than 100,000 Americans were treated with convalescent plasma after its use was authorized by US regulators in an emergency.