Australia Detects New Covid-19 Subvariants BA.4 and BA.5 as WHO Flags Mutant Strain Concerns

Australia has identified an uncommon Covid-19 variant, stirring concerns as several new strains begin to circulate across the region.

Melbourne authorities detected the new strain in the city’s wastewater, awaiting confirmation if it is the BA.4 or BA.5 subvariant of Omicron, both of which have emerged recently.

This particular variant, previously undetected in Australia, was found in the Tullamarine area, located in Melbourne’s northwest.

The discovery coincides with persistently high Covid case numbers as the busy Easter period approaches, a time when many people travel and gather, often on flights where social distancing is not enforced.

Australia recorded 54,048 new cases on Covid on Friday, continuing a trend of daily case numbers above 50,000 since late March.

Thirty-four deaths were recorded across the country. 

Brett Sutton, Victoria’s chief health minister said he was ‘not surprised but not worried’ by the arrival of the new strain.

‘The point with all the newly emergent lineages is that when they out-compete existing variants, we get upward pressure on cases and more risk of getting infected,’ he said on Twitter.  

The World Health Organisation’s director general confirmed the virus is becoming more infectious. 

‘This virus has over time become more transmissible and it remains deadly especially for the unprotected and unvaccinated that don’t have access to health care and antivirals,’ said Tedros Adhanom.

‘At present there are a number of Omicron sub-lineages we’re following closely, including BA.2, BA.4 and BA.5 and another recombinant detected, made up of BA.1 and BA.2.’ 

He said the best way to stay safe was get vaccinated and boosted if recommended. 

BA.4 and BA.5 Omicron have only been confirmed in a handful of cases mainly in southern Africa, Britain and Europe.

The early signs are that BA.4 and BA.5 are similar to other Omicron strains. 

But they are both considered ‘currently circulating variants of concern’ by the WHO, along with the XE recombinant strain, which was confirmed in a positive case in NSW. 

A traveller who returned to Australia from overseas tested positive to the XE strain according to NSW Health. 

NSW Health’s weekly Covid overview confirmed a single positive case in the last week of case data analysed. 

The XE strain is a combination of the two Omicron variant subtypes BA.1 and BA.2 and is said to be 10 per cent more transmissible than BA.2. 

‘One recombinant XE (BA.1/BA.2) has been identified in a specimen collected in the week ending 9 April 2022,’ NSW Health said. 

‘This is the first XE sequence to be identified in NSW and was identified in a recently returned traveller.’ 

Experts have warned the relaxation of restrictions and re-opened borders mean more cases are inevitable, with the arrival of other deadlier variants also highly likely. 

XE is understood to have characteristics of both previous strains and was first detected in January this year.

In Britain 1,125 XE cases have been reported and it has also been detected in Japan, India, Canada, Israel and Thailand.

XE is included in the World Health Organisation’s list of ‘currently circulating variants of concern’ under the Omicron label.

Delta is also still a current variant of concern.

So far experts believe existing vaccinations are effective against XE producing severe illness in most people because they work against BA.1 and BA.2.

But vaccines have proved less effective against symptomatic Omicron infection, including mild infections. 

There is also no early evidence it is any more severe than previous versions of Omicron. 

The British government’s UK Health Security Agency is also monitoring a further two notable variants.

They have been dubbed XF and XD, which are both recombinants of Delta and Omicron BA.1. 

The NSW Health Covid weekly report confirmed BA.2 ‘continues to be the dominant strain circulating’ in NSW.