Experts are proposing a smarter way to gauge Covid-19′s spread in New Zealand, as a heavily mutated new subvariant puts global health authorities on high alert.
Just days after New Zealand scrapped the last of its Covid-19 protections scientists have been closely tracking the new Omicron type BA.2.86, nicknamed Pirola, whose 36 mutations set it well apart from its closest relative.
So far detected in just a handful of countries, Pirola has been designated a “variant under monitoring” by the World Health Organization, amid growing concern it represents a large enough evolutionary leap to drive new waves.
“There are two really important questions with this variant,” Covid-19 modeller Professor Michael Plank told the Herald.
“One is the growth rate: if it doesn’t or can’t compete with variants that are currently in circulation, then it’s not going to have much of an impact.”
For around a year now, the coronavirus circulating in New Zealand has been made up of a “soup” of Omicron subvariants.
More recently, a succession of “recombinant” lineages classified as XBB, each packing some immune-evasion advantage, have emerged dominant.
But none have managed to trigger any major new surges in a population that’s now highly exposed to – and vaccinated against – the virus.
“The second one is, if it does have the legs to take off, then what does the severity look like?” Plank said.
Since the original virus that causes COVID, SARS-CoV-2, emerged in March 2020, it has mutated into dozens of variants, but most don’t differ too much from the “parents” they evolved from. However, a new variant scientists are bringing to our attention is about as genetically different from Omicron as Omicron was from the original “wild type” strain first detected in Wuhan, China in late 2019.
On Thursday, the Centers for Disease Control and Prevention (CDC) announced it was tracking a new lineage of the virus, BA.2.86, following the World Health Organization (WHO) adding the strain to its list of “variants under monitoring.” Originating in Israel, the variant has since appeared in Michigan in the U.S., three times in Denmark and once in the U.K., which has issued its own risk assessment.
Just six overall cases were reported worldwide as of Friday, but the fact that the variant, nicknamed “Pirola,” has already spread across multiple continents is “concerning,” said Dr. T. Ryan Gregory, an evolutionary and genome biologist at the University of Guelph in Canada.
“It’s not clear how big the impact could be if it were to take off,” Gregory told Salon in an email. “We do have some degree of population immunity against severe disease from vaccines and past infections, but the concern for quite some time is the potential for another ‘Omicron-like event,’ in which a very different new variant evolves and causes another major global wave.”
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While this new variant wasn’t given a new Greek-letter distinction like Alpha, Delta or Omicron, it is very different from the most current Greek-letter family of variant descendants: Omicron. While it shares about 30 of the same spike mutations, which allow the virus to attach itself more easily to receptors in cells, it also has 30 unique ones.
Specifically, there are about 57 mutations of the spike protein, which potentially increase its ability to cause infection, said Dr. Rajendram Rajnarayanan, of the New York Institute of Technology campus in Jonesboro, Arkansas. Most variants have around 20 to 30 mutations, he added.
“This is definitely going to spread,” Rajnarayanan told Salon in a phone interview. “This had all the necessary ingredients of being a successful lineage.”
“This is definitely going to spread. This had all the necessary ingredients of being a successful lineage.”
Scientists emphasized that this new variant isn’t yet a cause for alarm. Still, COVID infections are increasing internationally, and cases in the U.S. have returned to what is considered “high,” with 610,000 new infections per day. That’s more than triple the level recorded a month ago, which was around 185,000 cases per day, according to wastewater data used to estimate the spread of disease. However, this uptick in cases is not due to the new variant yet. Other closely-related variants like EG.5 and XBB.1.16 make up an estimated one-third of cases, with the rest caused by a couple dozen other variants, according to CDC data released Friday.