There is a new covid variant that causes infections. A virologist explains what you need to know about NB.1.8.1

While we are entering the coldest months in Australia, Covid is make the titles Again, this time because of the emergence of a new variant: NB.1.8.1.

Last week, the World Health Organization appointed nb.1.8.1 as “variant under surveillance“, Because of its growing global spread and certain notable characteristics which could distinguish it from previous variants.

So what should you know about this new variant?

The current situation coche

More than five years since Covid was initially declared pandemic, we still know regular waves of infections.

It is more difficult to follow the occurrence of the virus these days, as fewer people test and report infections. But available data suggests that at the end of May 2025, cases in Australia were tick.

The genomic sequencing confirmed that nb.1.8.1 is Among the circulating strains in Australia, and Generally growing. Sequenced cases until May 6 Throughout Australia, NB.1.8.1 varied by less than 10% in South Australia more than 40% in Victoria.

Wastewater monitoring in Western Australia determined NB.1.8.1 is now the dominant variant in wastewater samples collected in Perth.

International NB.1.8.1 is also growing. By End of April 2025It represented approximately 10.7% of all the sequences submitted – compared to only 2.5% four weeks earlier. Although the absolute number of sequenced cases is still modest, this constant rise in trend has caused narrower follow -up by international public health agencies.

NB.1.8.1 spread in particular in Asia – it was the dominant variant in Hong Kong and China At the end of April.

Where does this variant come from?

According to the WHO, NB.1.8.1 was detected for the first time from samples collected in January 2025.

It is a sub-line of the Omicron variant, descendant of the Recombinant XDV line. “”RecombinantThis is the place where a new variant stems from the genetic mixture of two existing or more variants.

The image on the right shows more specifically how nb.1.8.1 came.

What does research say?

Like his predecessors, nb.1.8.1 A series of mutations in the advanced protein. It is the protein on the surface of the virus which allows it to infect us – specifically via the ACE2 receiversA “door” of our cells.

THE Mutations include T22N, F59S, G184S, A435S, V445H and T478I. It is early for this variant, so we do not yet have much data on what these changes still mean. But a Recent pre -printed (A study that has not yet been evaluated by peers) provides clues to the reasons why NB.1.8.1 could collect the traction.

Using models based on the laboratory, the researchers found that NB.1.8.1 had the highest affinity of bonding to the human receptor ACE2 of several tested variants – suggesting that it can infect cells more effectively than previous strains.

The study also examined to what extent the antibodies of vaccinated or previously infected people could neutralize or “block” the variant. The results have shown that the neutralizing response of antibodies was approximately 1.5 times lower at NB.1.8.1 compared to another recent variant, LP.8.1.1.

This means that it is possible that a person infected with NB.1.8.1 may be more likely to transmit the virus to someone else, compared to previous variants.

What are the symptoms?

Until now, the evidence suggests that NB.1.8.1 can spread more easily and can partially develop immunity by previous infections or vaccination. These factors could explain its increase in sequencing data.

But above all, the WHO has not yet observed any evidence that it causes more serious illness Compared to other variants.

The reports suggest Symptoms of NB.1.8.1 should align closely with other omicron subvariants.

Common symptoms include sore throat, fatigue, fever, light cough, muscle pain and nasal congestion. Gastrointestinal symptoms can also occur in some cases.

What about the vaccine?

This variant may play an important role in the winter respiratory season of Australia. Public health responses remain focused on close surveillance, the continuation of the genomic sequencing and the promotion of the adoption of updated covored boosters.

Even if neutralizing antibody levels are modestly reduced Against NB.1.8.1, WHO noted the current coastal vaccines should still protect against serious illnesses with this variant.

The most recent booster available in Australia and many other countries Target Jn.1from which nb.1.8.1 went down. It is therefore logical that he always has good protection.

Before winter and with a new variant on the scene, perhaps the right time to consider another booster cocvid If you are eligible. For some people, especially those who are medically vulnerable, the coche can always be a serious illness.