This week, the BA.2 omicron subtype became dominant in the United States, showing that SARS-CoV-2, the virus that causes COVID, is evolving and spreading more than two years after the pandemic began.
The proliferation of new variants means it’s easier for people to contract COVID twice. One of those people was US billionaire Elon Musk.
On March 28th, Elon Musk, CEO of Tesla and SpaceX tweeted that he “allegedly” has COVID, having previously contracted it in 2020.
Musk explained that SARS-CoV-2, the virus that causes COVID, is “the virus of Theseus” — a reference to the philosophical thought experiment called the Ship of Theseus, which asks whether an object can even be considered the same object anymore its components are replaced.
He also asked, “How many gene changes before it’s no longer COVID-19?”
So is SARS-COV-2 really the “Theseus Virus”?
Sarah Otto is an evolutionary biologist at the University of British Columbia in Canada. she said news week that viruses “can evolve to the point where they are so diverse that they are termed not just a variant but an entirely new strain or pathogen”.
“To some extent, Omicron causes a significantly different disease than previous SARS-COV-2 variants,” she said. “If Omicron hadn’t emerged during the COVID-19 pandemic, we might be tempted to label it a different disease.”
The challenge, she said, is knowing when to call a virus a different virus altogether, or just a different variant. “In the end, labels are what’s useful for us. By calling Omicron a ‘Variant of COVID-19’ we understand it better.”
Nicola Stonehouse is a professor of molecular virology at the University of Leeds in the UK, she said news week that in order to classify a variant of SARS-CoV-2 as a completely different virus, there would not have to be any cross-protection against it.
“This would mean that previous infection and/or vaccination would not provide any protection at all,” Stonehouse said. “I think luckily we’re still a long way from that position!”
Andrew Rambaut is Professor of Molecular Evolution at the University of Edinburgh. He said while naming viruses is based on thresholds of genetic differences, it doesn’t take into account the fact that viruses evolve rapidly.
“For example, HIV-1 is much more diverse around the world today than it was when it was first sequenced in the 1980s,” Rambaut said news week. “If it were discovered and characterized now, it would likely be split into many different groups.”
“SARS-CoV-2 is defined as the virus first characterized in late 2019 and all progeny, regardless of how many variations occur.”
“It may diverge into two or more co-circulating lineages and could be given those names, like the Yamagata and Victoria lines of influenza B virus.”
However, he noted some exceptions. One would be if SARS-CoV-2 combined with another type of circulating coronavirus, in which case “that would probably get a new name.”
Another possibility would be the emergence of another virus from the same animal reservoir that may have given rise to SARS-CoV-2. This, Rambaut said, would “probably be called SARS-CoV-3”.
Experts have said it is hypothetically possible for a virus – including SARS-COV-2 – to evolve to the point where it can no longer be considered the same virus it once was. But scientists say that’s not the case with COVID right now.
NEWSWEEK FACT CHECK