As Australia grapples with a new COVID-19 variant, health officials are raising concerns about the rising incidence of NB.1.8.1, a subvariant of the Omicron lineage. Over five years since COVID-19 was classified as a pandemic, this new strain has been detected across several states just as winter approaches.
The World Health Organisation (WHO) has labelled NB.1.8.1 as a “variant under monitoring”, highlighting its international spread, which has resulted in hospitalisations in regions including Hong Kong, mainland China, and parts of the United States. In Australia, Griffith University has reported that NB.1.8.1 is contributing significantly to new COVID-19 cases, accounting for less than 10% of infections in South Australia and more than 40% in Victoria, according to sequencing data from early this month.
In Western Australia, wastewater testing indicates that NB.1.8.1 has become the predominant variant within samples collected in Perth. The latest Respiratory Surveillance Report from New South Wales confirms that COVID-19 activity levels are moderate, with the new variant contributing to an uptick in cases. Health Minister Mark Butler is urging Australians to ensure their COVID-19 vaccinations, particularly as the winter season approaches.
Butler emphasised the importance of booster shots, advising those over 75 to receive another vaccination if it has been over six months since their last dose, while those aged 65 to 74 should also consider getting boosted if it has been more than 12 months. He encourages all eligible individuals to reflect on their vaccination history as the colder months draw near.
The WHO noted that the NB.1.8.1 variant was first identified in samples from late January 2025. As a member of the extensive Omicron family, typical symptoms include sore throat, fatigue, fever, mild cough, muscle aches, and nasal congestion, with some individuals experiencing gastrointestinal issues. Although there has been no evidence to suggest that this variant causes more severe disease, it may be more transmissible and could potentially evade existing immunity from prior vaccinations.
Fortunately, current vaccines are expected to provide protection against severe illness from NB.1.8.1, with the latest booster targeting JN.1, from which this new variant has descended. Thus, individuals who are vaccinated should still have robust protection against this latest strain. As Australia faces this evolving health challenge, staying up-to-date with vaccinations remains crucial for public health.