An article published in the Yale Medicine Review on August 31 has noted the rise of Covid-19 infections in multiple countries, driven by a new Coronavirus variant called BA.2.86, which is informally being termed ‘Pirola’.
While the report says that it is too early to know if this strain is any more transmissible than other ones, there may be a reason to worry. The report says it has “more than 30 mutations to its spike protein compared to XBB.1.5, a variant of Omicron that had been the dominant strain in the United States… The spike protein is how the coronavirus enters human cells.”
Here’s what we know so far.
According to Yale Medicine infectious diseases specialist Scott Roberts, MD, the high number of mutations is a point of concern here. He said in the report that this was similar to the number of mutations that differed between Delta, one of the early strains of the coronavirus, and Omicron (that was dominant in the winter of 2021).
“With every respiratory virus, as it spreads from person to person, it evolves gradually over time. But these massive shifts, which we also saw from Delta to Omicron, are worrisome… The other concern is that this strain has been picked up in at least six countries, and the cases are unrelated. This suggests some degree of transmission in the [international] community that we’re not detecting,” he said.
It is natural for all viruses to mutate over time and such changes are particularly common in viruses that have RNA as their genetic material, as in the case of coronaviruses and influenza viruses.
Once a virus enters the human body, its genetic material — RNA or DNA — enters the cells and starts making copies of itself which can infect the other cells. Whenever an error occurs during this copying process, it triggers a mutation.
Occasionally, a mutation comes along when the genetic mistakes that are introduced while copying prove to be advantageous for the virus — these help the virus copy itself or enter human cells more easily. Whenever a virus is widely circulating in a population, the more it spreads and replicates, its chances of mutating increases.
Speaking to the Yale School of Medicine, Anne Hahn, a postdoctoral associate who leads the Yale SARS-CoV-2 Genomic Surveillance Initiative, said that this is a “much more interesting subvariant”, when compared to the Omicron subvariant known as XBB.1.9. That variant initially spread quickly but did not overwhelm populations at a significant scale.
The same report noted that it has been detected by surveillance labs in Israel and Denmark and later in labs in England, South Africa, and the United States.
According to Fortune, new data released on Twitter on Friday evening by Ben Murrell, a researcher at the Karolinska Institutet in Sweden, showed that blood samples taken last week performed better than expected when it came to neutralising BA.2.86.
Dr Eric Topol, a professor of molecular medicine at Scripps Research and founder and director of the Scripps Research Translational Institute, said in a tweet that the findings offer a more positive outlook for how new boosters might protect against the highly mutated variant.
So far, no deaths have been reported among cases, according to the WHO. As of last week, an elderly man in Europe was hospitalised with the strain, according to Fortune. As of a few weeks ago, rising Covid-19 cases in the US were mostly a result of the Eris variant.
What precautions need to be kept in mind against this new variant?
Roberts said that the US Centres for Disease Control and Prevention’s (CDC) preliminary report says there is not enough evidence right now to conclude whether Pirola could lead to more severe disease, death, or hospitalisation. “We don’t yet know how transmissible it is, and it’s very possible it doesn’t spread that well and we would see this peter out in a couple of weeks,” Dr Roberts said.
He added, “But it’s important to remember that it’s still the same virus at its core, so the same prevention methods — masking, vaccination, and hand-washing, among others — can help people avoid infection.”