SARS-CoV-2 Mutations Allow Virus to Escape Immune Defenses

A recent study conducted by investigators from Harvard Medical School has shown that the SARS-CoV-2 virus is capable of mutating and evading naturally occurring and lab-made antibodies, demonstrating how COVID-19 survives under immune pressures. Results from the study were published in the journal Cell.

The research builds on an initial case report, published in The New England Journal of Medicine, which showed a patient-derived variant with a cluster of changes on its spike protein. Some of the changes identified were later seen in viral samples of both the UK and South African strains of COVID-19.

However, in the new study, the investigators found that some of the changes have yet to be seen in the dominant strains and they fear that they could eventually lead to other viral mutants that spread through the population.

For the study, the investigators created lab-made, noninfectious replicas of the virus found in the original patient and exposed it to both antibody-rich plasma from COVID-19 survivors and to antibodies made pharmaceutically.

Findings showed that the virus was able to evade both types of antibodies.

"Our experiments demonstrated that structural changes to the viral spike protein offer workarounds that allow the virus to escape antibody neutralization,” Jonathan Abraham, a senior author on the study said. “The concern here is that an accumulation of changes to the spike protein over time could impact the long-term effectiveness of monoclonal antibody therapies and vaccines that target the spike protein."

Though the investigators stress that the situation is only hypothetical, at least for now, it highlights 2 important things. The first is the need to curb the growth and spread of mutations through prevention measures and widespread vaccination, and the second being the need to continue developing vaccines and therapies that target less mutable parts of SARS-CoV-2.

"It is important for us to stay ahead of this virus as it continues to evolve," Sarah Clark, a first author on the study said. "My hope is that our study provides insights that allow us to continue to do that."