A New COVID Threat This Winter? NB.1.8.1 in Australia
As winter chills set in across Australia, a new COVID-19 variant, NB.1.8.1, is causing a stir among health professionals. Officially classified as a "variant under monitoring" by the World Health Organization (WHO), it's showing up more and more in case numbers and genomic sequencing data. Honestly, it's a bit concerning.
The Numbers are Rising
While fewer Australians are getting tested for COVID-19 these days, the data we do have points to a rise in infections since late May 2025. This increase is strongly linked to NB.1.8.1, an Omicron sublineage first spotted back in January. It's spreading across multiple states. In Victoria, for example, it made up over 40% of sequenced cases in early May. In South Australia, it was under 10%, but that's still significant. Even more worrying? In Perth, wastewater surveillance indicates it’s now the dominant strain. Globally, it's a similar story – by late April, it accounted for more than 10% of sequenced cases worldwide, a huge jump from 2.5% just four weeks earlier.
What Makes NB.1.8.1 Different?
NB.1.8.1 comes from the Omicron XDV recombinant lineage. What does that mean? Essentially, it's a mix of different COVID-19 strains that have swapped genetic material, creating a virus with unique properties. It boasts several mutations in its spike protein, which is the key that lets the virus unlock and infect our cells. Early lab studies suggest this variant might bind to our cells even better than previous strains, possibly making it easier to catch and spread.
Vaccines: Still Our Best Defense?
The good news? While early research shows that neutralizing antibodies are slightly less effective against NB.1.8.1 compared to some other recent variants, existing COVID-19 vaccines are still expected to offer substantial protection against severe illness. Australia's latest vaccine boosters target the JN.1 lineage, a parent to NB.1.8.1, so health officials are optimistic that those boosters should give you a good level of protection, especially from serious complications.
Still, they’re strongly recommending that everyone eligible get boosted, especially as we head into winter.
Symptoms: Sounds Familiar
The symptoms of NB.1.8.1 seem pretty similar to previous Omicron variants. Think:
- Sore throat
- Fatigue
- Mild fever
- Dry or mild cough
- Muscle aches
- Nasal congestion
- Possible gastrointestinal issues
There's no evidence yet that this variant leads to more severe illness, but its increased spread and ability to partially bypass immunity are definitely cause for concern.
What Should We Do?
With NB.1.8.1 potentially dominating this winter's respiratory season, it's crucial we stay vigilant. The advice is simple but effective:
- Get vaccinated and boosted if eligible.
- Stay home if you feel unwell.
- Use rapid antigen tests when needed.
- Wear a mask in crowded indoor spaces.
- Practice good hand hygiene and social distancing where possible.
Even though the WHO hasn’t seen a spike in severe cases, we need to protect those most at risk.
Looking Ahead
COVID-19 continues to evolve, and NB.1.8.1 serves as a reminder that we can't let our guard down. While we're learning to live with the virus, staying informed, maintaining public health measures, and keeping up with vaccinations is still key to minimizing the impact of new variants. Let's stay proactive and protect ourselves and our communities.
