Fresh plasma from Covid-19 recovering subjects.
Photographer: Omar Marques / Getty Images
Photographer: Omar Marques / Getty Images
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British doctors who spent 102 days treating a cancer patient for Covid-19 documented how the virus mutated after the man was treated with restorative plasma.
The case study suggests that the use of blood plasma donated by Covid-19 survivors may have put enough pressure on the virus for it to evolve. The result: less susceptibility to immune system antibodies that normally fight infection, according to the report published Friday in the journal Nature.
While the restorative plasma did not appear to harm the patient, it did not provide a clear benefit, senior author said Ravindra Gupta, Professor of Clinical Microbiology at Cambridge Institute of Therapeutic Immunology and Infectious Disease. It should be used with caution in people with chronic immune conditions, he said, preferably in clinical trials or carefully controlled settings.
The report also suggests that numerous mutations can develop in patients with compromised immune systems as well as chronic infections.
“If the virus is allowed to stay in one person for a long time and replicate for weeks and months, it learns how to fight the immune system,” said Gupta. It’s all about “hit 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 said, but it did have certain elements in common. “It just illustrates that someone like him is probably zero,” said Gupta.
Slow mutations
Overall, Covid-19 mutates relatively slowly. That’s because it is a fast-moving virus, so it has little time to develop. In this case, however, the patient and his doctors fought the virus for 102 days from when he was diagnosed until his death, Gupta said.
The patient was diagnosed with Covid-19 in a local hospital in the spring of 2020, when the first wave of the virus hit a crisis in the UK. He was then 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 The brake desivir from Gilead Sciences Inc. decreased its viral load. There were not.
Genetic profiling
At the same time, the samples were sent for genetic profiling. That resulted in a snapshot of the virus mutating over time, allowing the researchers to track where, how, and when the pathogen changed as the months progressed.
The virus changed little after he received two courses of remdesivir in the first two months, the researchers said. However, after restorative plasma was administered, there were large, dynamic shifts in the virus population, including in the major spike protein, which the virus uses to join and infect healthy cells.
The variants then showed evidence of reduced sensitivity to neutralizing antibodies that normally control the virus.
Big study
The case study comes almost a month after one large, national study in the UK investigating restorative plasma as a therapy ended after finding that the treatment touted by US President Donald Trump is not working.
The The University of Oxford research was part of a clinical trial called Recovery, which is investigating several Covid-19 treatments. The other branches of the investigation are underway.
The results come after more than 100,000 Americans have been treated with restorative plasma after its emergency use was approved by US regulators.