As the days draw darker and the weather gets colder, a new family of COVID-causing subvariants has arrived just in time for Australia’s sniffles season. 

The family has been nicknamed FLiRT and is made up of several similar subvariants — namely KP.1 and KP.2 — but they are not as playful or amorous as the name would suggest.

FLiRT derives from the much more boringly named JN.1 variant, which is more transmissible than previous iterations of the coronavirus but usually causes less severe illness than those earlier versions. 

In the United States, FLiRT has quickly overtaken JN.1 as the dominant strain — a scenario likely to play out here too, with cases already on the rise.

The World Health Organization (WHO) is tracking several of these JN.1 descendants and told the ABC it would soon classify some of these as Variants Under Monitoring (VUM).

VUM is a term used to signal when a variant may require increased attention and monitoring because of its potential impact on global health.

What makes FLiRT different?

As close direct descendants of the dominant JN.1 strain, this family of variants shares similar traits.

Back in January of this year, we wrote about the JN.1 variant and described it as being a bit like a grandchild of Omicron, which typically led to less severe disease than earlier versions. 

Following that same analogy, the FLiRT family are a bit like children of JN.1.

The name FLiRT was coined as a play on words and relates to the location of the additional mutations in the spike protein of these variants: they’re changes typically seen at R346T, F456L and V1104L.

Virologist Stuart Turville says FLiRT is better than previous COVID strains at navigating antibodies, which the body produces to fight viruses.(Freepik: kjpargeter)

Associate professor Stuart Turville is a virologist at the Kirby Institute, with the University of New South Wales.

“It’s essentially JN.1, but it’s got a few changes which could make it navigate a bit better through immunity,” he said. 

“The way it gets a competitive advantage in the community is it essentially starts to have changes which give it a better ability to navigate antibodies.”

While JN.1 only had one additional spike protein mutation compared to this previous one, that tiny change made it more transmissible.

FLiRT appears to be even more so and that’s what’s causing a spike in cases.

What are the symptoms?

Because FLiRT is so closely aligned to JN.1, the symptoms are pretty much the same as more recent versions.

Some people will feel very unwell while others will experience only mild symptoms.

However, FLiRT’s ability to evade the immune system means we could see lots of people becoming ill, adding pressure to the nation’s health system.

Getting an idea of official figures is difficult because fewer people now test and register their cases.

However, NSW Health says COVID-19 have increased to “moderate” levels.

For the week ending on May 11, there were 2,820 positive cases officially recorded in the state.

Concerningly, a substantial portion of new cases were in people aged 90 and older.

Likewise, in Queensland, 47 per cent of people hospitalised with COVID-19 last week were aged 75 years or older.

In Victoria, wastewater measures indicate an increase in cases there too.

While 97 per cent of samples tested were for the JN.1 strain, new FLiRT variants are also being detected.

Hospitalisations for the week ending May 17 averaged 284 compared to 208 the week prior.

A significant proportion of COVID-19 cases recorded recently have been detected in people aged over 75.(AAP: Supplied by State Library of Victoria, Fabiana Guerreiro)

South Australia had 1,528 new cases for the week ending May 17, along with 27 COVID-related deaths.

In the Australian Capital Territory, four people died with COVID for the week ending May 16 and 146 new cases were detected.

The Northern Territory doesn’t record COVID data.

But in Western Australia, cases increased by a massive 83 per cent for the fortnight ending May 12, with 1,095 recorded along with 15 deaths.

Meanwhile, cases in Tasmania are increasing.

Doctors are urging people to take steps to protect themselves and others.

They recommend staying home when sick, having good hygiene and sanitation practices, ensuring there is enough ventilation where possible, and calling a general practitioner (GP) for advice if symptoms worsen.

President of the Royal Australian College of GPs Nicole Higgins also suggests staying on top of immunisations.

“If you haven’t had your flu vax and COVID booster, if eligible, then now is the time,” said Dr Higgins.

“We want to protect our health workers and teams in general practice and hospitals.

“We have choices for care including telehealth to enable people to stay at home.”

Why do we keep seeing new variants?

Since it was first detected in China in late 2019, SARS-CoV-2, the virus that causes COVID-19, has changed.

Part of the reason is that this is exactly what viruses do: they evolve.

Most of the time, these changes are small and happen with little consequence.

However, as the WHO explains, some changes affect a virus’s properties including how easily it spreads or the severity of disease it causes or even how it responds to therapies like medicines and vaccines.

Dr Turville says scientists are still trying to understand why the virus behaves like it does. (Supplied: CSIRO)

“Every year we appear to have one that enters the mix that is really different: JN.1 was one of those,” Dr Turville said.

“So, back in 2020, we saw this with the first variants of concern. We saw this with the Gamma, we saw it with Beta with Alpha.

“Then eventually we got Delta.” 

While scientists always expected the virus to change, they have been surprised by the trajectory of this one and are still trying to understand why it is behaving the way it is.

“The virus has changed over time, but we’re still scratching our heads in the context of how and why it’s done it, and how it’s contributing towards just disease severity.

“Towards the end of each year, we have this kind of seismic shift, or a new [variant] turns up.

“We’re trying to get a hint around where they’re coming from … the current hypothesis is that it’s from chronically infected individuals.” 

That unknown is making it difficult to predict.

The WHO agreed, telling the ABC it did “not yet have seasonal/predictable temporal or evolutionary patterns.”

What does this mean for COVID vaccines?

Nothing yet, but change is afoot.

Doctors and scientists agree that the available vaccine is the most effective one for those who are eligible and want one.

However, the WHO is recommending that “future COVID-19 vaccines be based on JN.1 so as to offer protection against future JN.1 descendant lineages.”

Even so, it will still be several months before any updated vaccines are developed.

They will then need regulatory approval.

Until then, the Australian Technical Advisory Group on Immunisation (ATAGI) advises adults aged 18 to 64 to consider getting a COVID-19 vaccine every 12 months.

Those who are severely immunocompromised are advised to consider vaccinations more frequently.

As always, the best advice is to chat with your GP about what suits you the best.

If you’ve had the latest COVID strain the ABC would like to speak with you. You can contact us via the form below.

Posted , updated