Small Genetic Mutation Can Change How SARS-CoV-2 Behaves: Study

Could one tiny mutation predict the next pandemic? Scientists think it's possible.

Illustration of SARS-CoV-2, the virus responsible for COVID-19, highlighting its distinctive spike proteins.

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• Identifying these genetic changes strengthens future pandemic preparedness efforts.

Although viruses are known to undergo continual mutation, not all genetic alterations have a significant effect. Sometimes, a single mutation can change a virus's behavior, its ability to spread and even whether it can infect a new species. The World Health Organization (WHO) states that as viruses reproduce, they naturally pick up mutations, some of which can alter their transmissibility, severity or capacity to adapt to new hosts. Researchers who want to forecast and stop future outbreaks have made it a top priority to comprehend these genetic changes.

Researchers from the University of California, San Francisco (UCSF) and partner institutions have discovered a single genetic alteration that seems to affect how closely related coronaviruses behave in various species. The results, which were published in the journal Cell Host & Microbe, provide new information about how animal viruses might develop the capacity to infect people and cause illness.

Tiny Difference With Major Consequences

RaTG13, a closely similar coronavirus found in bats and SARS-CoV-2, the virus that causes COVID-19, were compared by the researchers. Despite having a similar genetic composition, the two viruses interact with their hosts in somewhat distinct ways.

In order to find out why, researchers created the first laboratory-grown lung cell line from the larger horseshoe bat, which enables them to examine the behaviour of both viruses in human and bat lung cells under comparable circumstances. They concentrated on Orf9b, a viral protein that aids coronaviruses in avoiding the host's immune system. Surprisingly, there was just one amino acid difference across the Orf9b proteins, yet that small difference significantly altered how each virus interacted with immune defences. 

The study found that the SARS-CoV-2 form of the protein was far more successful in inhibiting the body's initial antiviral response, which allowed the virus to multiply more effectively in human cells.

Why The Discovery Matters

The results, according to scientists, advance our knowledge of spillover events, the process by which viruses that are circulating in animals adapt and infect humans. Animal coronaviruses were the source of earlier outbreaks such as SARS, MERS and COVID-19, before they spread to humans.

The WHO states that it is crucial to keep an eye on viral evolution because changes that enhance a virus's capacity to infect new hosts or elude immune responses might lead to the creation of new variations. Finding the mutations with the biggest biological impact could help bolster international surveillance networks and increase readiness for pandemics in the future.

These kinds of findings, according to researchers, may help them better identify high-risk viruses before they cause epidemics. The US Centers for Disease Control and Prevention (CDC) states that genome surveillance makes it possible for scientists to track the evolution of viruses, spot significant alterations and react more quickly to new dangers to public health. While viruses are still circulating in animal populations, scientists aim to find genetic fingerprints associated with immune evasion or improved infectivity rather than waiting for a virus to proliferate widely.

Not Every Mutation Leads To A New Pandemic

The finding does not imply that a single mutation can start a new pandemic, researchers warn. Before a virus can establish long-term transmission in people, it must overcome several biological obstacles. A virus's ability to transmit between individuals is influenced by a number of factors, including receptor binding, immune evasion, viral replication and environmental factors. However, scientists think the discovery offers a crucial piece of the puzzle.

Researchers may be able to identify potentially harmful animal viruses sooner and prioritise them for surveillance by identifying genetic alterations that increase a virus's capacity to suppress immune defences. Such findings could be crucial in bolstering pandemic preparedness and directing the creation of next-generation antiviral treatments and vaccines as genome sequencing advances globally.