Australia Braces For Omicron Reinfections Amid Arrival Of BA. 4 Sub-Variant

A new sub-variant of the Omicron strain has been detected in NSW prompting warning to potential risks of reinfection.

The arrival of the highly contagious Omicron sub-variant BA.4 strain means there is a likely chance of second or even third infections.

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The latest mutation arrived in Australia with a traveller returning from South Africa who tested positive for the sub-variant in late March.

Flagged by the World Health Organisation (WHO) as a new strain with the capabilities to better evade the immune system of those vaccinated, the NSW Health took three weeks to confirm the case as the first recorded instance of the new variant to hit Australian shores.

The WHO has warned that the new strain may contain mutations that may be better at evading the immune system in those that are already vaccinated.

The BA. 4 variant is now the dominant virus in Africa and South Africa.

Former WHO epidemiologist, Professor Adrian Esterman confirmed the latest sub-variant is likely to result in more reinfections.

“It appears to have same intrinsic transmissibility as BA. 2, but can more easily evade immunity – that is, it can more easily reinfect people, or infect those who are vaccinated,” he told NCA NewsWire.

With each person possessing their own unique immune response, Professor Esterman said there are no absolutes.

"The question is 'why can they catch it twice?' And the thing is that when you first get infected, your body generates an immune response to the virus, and that response can last for several months and protect you from future infection. But up to a third of people have no immune response at all, meaning they get no protection," he explained to MamaMia.

"The younger and fitter you are, the more robust your immune system is - especially those in their 20s and 30s. But everyone is different. You can put two people together who look identical, are the same age, same sex, same background, same fitness, same exposure to the virus, and they both may experience something different."

"We just don't know why some get seriously sick and others don't. There's probably more things we don't know about COVID-19 than we do know," he admitted.

The warning comes as the latest data from overseas reveals a large cohort of people have caught the virus twice, especially after the highly transmissible Omicron variant arrived.

Meanwhile, Covid cases and hospitalisations across Australia and New Zealand look like this:

Western Australia 

• New cases: 8,117 
• Covid-related deaths: 2
• Hospital and ICU admissions: 233 / 4  

Northern Territory 

• New cases: TBA
• Covid-related deaths: TBA
• Hospital and ICU admissions: TBA

Australian Capital Territory 

• New cases: 1,072   
• Covid-related deaths: 0 
• Hospital and ICU admissions: 65 / 3

Queensland 

• New cases: 4,477
• Covid-related deaths: 6
• Hospital and ICU admissions: 492 / 11 

New South Wales 

• New cases: 11,903
• Covid-related deaths: 7
• Hospital and ICU admissions: 1,645 / 68

Victoria 

• New cases: 11,083
• Covid-related deaths: 7 
• Hospital and ICU admissions: 428 / 35

South Australia 

• New cases: TBA
• Covid-related deaths: TBA
• Hospital and ICU admissions: TBA

Tasmania 

• New cases: 1,090
• Covid-related deaths: 1
• Hospital and ICU admissions: 37 / 3

New Zealand 

• New cases: 8,242 
• Covid-related deaths: 14
• Hospital and ICU admissions: 480 / 15 

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