Fresh Covid-19 convalescent plasma.
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 mutated after the man was treated with convalescent plasma.
The case study suggests that donated blood plasma use from Covid-19 survivors may have put enough pressure on the virus to force it to evolve. The result: less susceptibility to antibodies in the immune system that normally fight infection, according to the report published Friday in the journal Nature.
Although convalescent plasma did not appear to harm the patient, it did not offer any clear benefit, the lead author said. Ravindra Gupta, Professor of Clinical Microbiology at the Cambridge Institute of Therapeutic Immunology and Infectious Diseases. It should be used with caution in people with chronic immune conditions, he said, preferably in clinical trials or in carefully controlled environments.
The report also suggests that numerous mutations may appear among patients who have a compromised immune system and chronic infections.
“When the virus has a chance to sit in one person for a long time and reproduces for weeks and months, it learns to fight the immune system,” Gupta said. This is “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, according to the report, but it had certain elements in common. “It just illustrates that someone like him is probably a zero patient,” Gupta said.
Slow mutations
Overall, Covid-19 is mutating relatively slowly. This is because it is a virus that moves quickly and gives you little time to evolve. In this case, however, the patient and his doctors fought the virus for 102 days from being 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. remdesivir it reduced its viral load. They were not.
Genetic profiles
At the same time, samples were sent for a genetic profile. This resulted in a snapshot of the mutant virus over time, which allowed researchers to know where, how and when the pathogen changed as the months progressed.
There were few changes in the virus after it received two courses of remdesivir in the first two months, according to the researchers. However, after convalescent plasma administration, large dynamic changes in virus population occurred, including the key key protein, which the virus uses to target and infect healthy cells.
The variants then presented evidence of reduced susceptibility to neutralizing antibodies that normally control the virus.
Great study
The case study comes almost a month after one A large national study in the UK examining convalescent plasma as therapy was completed after finding that the treatment proposed by US President Donald Trump is not working.
He Oxford University research was part of a clinical trial called Recovery that investigates different Covid-19 treatments. The rest of the arms of the studio are in progress.
The results come after more than 100,000 Americans were treated with convalescent plasma after U.S. regulators authorized its use in emergencies.