U.K. variant spreading in the U.S. as COVID mutations raise stakes


Warning from British scientists to the world

Despite these genomic accomplishments, some British scientists said they have regrets too, wishing they’d known just how rapidly SARS-CoV-2 was actually spreading a year ago, when it hit western Europe.

That information was crucial not only for preventive efforts, but because viruses inevitably mutate faster the more people who are infected, said Igor Rudan, MD, PhD, director of the Center for Global Health Research at University of Edinburgh.

“Italy showed us just how fast it was spreading and how deadly it is for the very old and people with multiple comorbidities,” said Dr. Rudan, who also editor in chief of the Journal of Global Health. “We wish we knew it was spreading so fast, and we wish we knew the threshold of cases we could allow to be infected before the virus would mutate.”

More mutations mean more new strains of SARS-CoV-2, Dr. Rudan said in an interview. “We’ve reached that threshold now and will see more of these mutations.”

Despite its current struggles, the United Kingdom is reaching beyond tracking its new variant’s spread and trying to identify new mutations that might change the way the virus behaves.

Three features of any emerging variant are particularly important, Dr. Peacock explained: Is it more transmissible? Is it more lethal? And does it cut the ability of natural- or vaccine-induced immunity to protect people from infection?

“We need to sequence people coming to the hospital who are sicker,” said Dr. Peacock, also a professor of public health and microbiology at the University of Cambridge (England). “Also, if anyone has the infection after they’ve already been sick or had the vaccine, we really want to know what that looks like” genomically.

SARS-CoV-2 has already logged more than 4,000 mutations, Dr. Peacock said. But “knowing that viruses mutate all the time is not sufficient reason not to look. We really want to know if mutations lead to changes in amino acids, and if that can lead to changes in functionality.”

For the moment, however, experts say they’re relieved that the U.K. strain doesn’t seem able to evade COVID-19 vaccines or render them less effective.

“Even though mutations are common, those able to change the viral coding are rare,” Dr. Brito explained. If necessary, vaccines could be tweaked to replace the spike gene sequence “within a matter of weeks. We already do this for flu vaccines. Every year, we have to monitor variants of the virus circulating to develop a vaccine that covers most of them. If we end up having to do it for SARS-CoV-2, I would not be surprised.”

But variant-fueled increases in infections will require more people to be vaccinated before herd immunity can be achieved, Dr. Rudan warned. “If it spreads faster, we’ll need to vaccinate probably 85% of people versus 70% to reach herd immunity.”

One lesson the COVID-19 pandemic has driven home “is to always be on your guard about what happens next,” Dr. Peacock said. Although confident about the genomic efforts in the United Kingdom to date, she and her colleagues feel they’re still reaching for a complete understanding of the evolutionary changes of the virus.

“We’re ahead of the curve right now, but we want to get in front of the curve,” Dr. Peacock said. “It’s essential to get ahead of what might be around the corner because we don’t know how the virus is going to evolve.”

A version of this article first appeared on Medscape.com.


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