May 22, 2024

New Variants of SARS-CoV-2 Develop Strategies to Evade Immune Defenses, says UCL Study

A recent study conducted by researchers from University College London (UCL) has found that newer variants of SARS-CoV-2, such as BA.4 and BA.5, have developed the ability to overcome humans’ innate immunity. The study, published in Nature Microbiology, examined the viral evolution of eight different omicron variants to understand how the virus has evolved in response to vaccinations.

Previous research has shown that the alpha and delta variants were able to overcome human innate immunity by disrupting the cellular signaling that triggers the antiviral immune response. This allowed the virus to establish itself in the body and evade the adaptive immune response. In contrast, the evolution of the omicron variant was driven by the pre-existing immunity in the population due to vaccination and prior infection.

The researchers found that the earliest omicron variants, BA.1 and BA.2, were less effective at evading innate immunity compared to the alpha and delta variants. However, more recent omicron variants, such as BA.5 and XBB, had reacquired the ability to overcome innate immunity in a similar way to alpha and delta.

Dr. Ann-Kathrin Reuschl, the first author of the study, noted the surprising finding that the early omicron sub-variants were relatively ineffective at evading innate immunity compared to alpha and delta. This may explain why these variants were associated with reduced disease severity. The researchers also found that the later omicron variants produced larger quantities of viral proteins that interfere with the cellular signaling pathways involved in the antiviral response.

Professor Greg Towers, a senior author of the study, emphasized the importance of understanding how the virus evolves and adapts to maximize human-to-human transmission. The study suggests that avoiding neutralizing antibodies may be more critical for transmission than evading innate immunity. However, the ability to overcome innate immunity remains an essential strategy for the virus.

The findings of the study help explain why SARS-CoV-2 is still capable of infecting vaccinated individuals or those with prior infection. To prevent infection, wearing FFP3 masks or similar protective measures that can effectively filter out the virus breathed out by infected individuals is recommended.

Professor Clare Jolly, another senior author of the study, highlighted the unique opportunity provided by the COVID-19 pandemic to observe the evolution of a virus in real-time. This knowledge can be used to assess the risk posed by emerging viruses and new variants of existing viruses. Ongoing monitoring of the virus’s evolution is crucial to stay ahead of its strategies.

In conclusion, the study from UCL sheds light on how SARS-CoV-2 variants have developed mechanisms to evade immune defenses. The ability of the virus to adapt and overcome innate immunity highlights the need for continuous surveillance and research to combat the ongoing COVID-19 pandemic effectively.

1. Source: Coherent Market Insights, Public sources, Desk research
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