Health authorities have expressed their concern over the spread of a new variant of COVID-19, with NSW Premier Dominic Perrottet saying they would “tailor settings” if needed.

A new subvariant of Omicron, called BA.2, has been recorded across the globe and is the dominating strain in at least 18 countries.

Currently, the BA.1 Omicron variant remains the top strain in NSW and Victoria, though NSW Health Minister Brad Hazzard said BA.2 could quickly overtake it and cause cases to double within the next four to six weeks.

Other states, including Victoria, are expected to follow suit.

It comes as both NSW and Victoria recorded a drop in cases on Friday after experiencing 16,288 and 7779 new cases on Thursday.

Appearing on Sunrise, Mr Perrottet said that boosters were the best protection against the new variant, and that authorities would “tailor settings” if required.

“The best thing we can do is get boosted,” he said.

“The virus is not going away.”

BA.2 explained

The Omicron variant of Covid, the dominant version circulating around the world, is made up of several subvariants called BA.1, BA.2, BA.3 and BA.4, with BA.1 and BA.2 being the most common.

These two subvariants differ in their genetic sequences, with some studies finding BA.2 has a growth advantage over BA.1. According to Richard Kuhn, a professor of biological sciences at Purdue University, a variant with a growth advantage is better than the original virus, meaning it can evolve and be “successful” at spreading.

In a statement, the WHO pointed to initial data suggesting BA.2 appears to be more transmissible than BA.1, though the difference between them is less stark than the difference in transmissibility of Omicron BA.1 versus the Delta strain.

Can I get BA.2 if I’ve already had Covid?

Though studies investigating BA.2 are ongoing, some initial data suggests that people who have been infected with the Omicron variant are protected from reinfection with BA.2 “for the limited period for which data are available”.

In a Danish study, which is yet to be published or peer-reviewed by other scientists, they sequenced samples from 263 people who had been infected with COVID-19 twice between November 11, 2021 and February 11, 2022.

Of these, 47 were found to have contracted BA.1 first and BA.2 second, 50 contracted the same variant twice, and 140 contracted BA.2 after they were infected with Delta.

Out of those 47 people, the majority were unvaccinated, under the age of 20, and experienced mild symptoms.

The WHO’s Technical Advisory Group on SARS-CoV-2 Virus Evolution (TAG-VE) also considered data from South Africa, the UK, and Denmark to assess the severity of disease caused by BA.2, finding that there was no “reported difference” between it and BA.1.

Image: Getty Images

This article first appeared on OverSixty.