Just as COVID-19 and influenza numbers begin to ease, NSW health has found a little known virus has spread like wildfire across the state in just a matter of weeks.
More than 1,245 cases of human metapneumovirus, also known as hMPV, has been reported to the NSW Health Department's respiratory surveillance report for the week ending September 24.
What is this virus and just how dangerous is it?

What is HmVP?
hMPV is a respiratory virus that commonly pops up in winter and spring.
The virus is alike to other respiratory viruses, such as RSV or influenza, with similar symptoms like COVID-19 or the common cold.
These include coughing, wheezing, shortness of breath and nasal congestion.
Institute for Glycomics at Griffith University Dr Larissa Dirr said the virus was not something to take lightly as it could leave those most vulnerable hospitalised.
"Human metapneumovirus infections pose an important threat to the health of infants, elderly, and immunocompromised people, such as transplant patients, who are most at risk of contracting hMPV, and developing severe disease, such as pneumonia or bronchiolitis," she said.
hMPV is also known to spread quite easily from person-to-person through just a simple cough or shaking hands.
But throughout your lifetime you have most likely been infected.
"Global studies have found that child under the age of five have encountered hMPV at one point in their life with the percentage of children who are hospitalised due to an hMPV infection being 10-12 per cent," Dr Dirr said.
"hMPV infections are not endemic to any particular region but occur periodically around the world."
New or old virus?
The virus was officially discovered in the Netherlands back in 2001. But scientists do not believe this to be a new virus.
"hMPV has likely infected humans for decades if not centuries before its discovery- we just didn't have the technology to identify it as the cause of common respiratory illnesses," Dr Mary Petrone from Sydney Institute for Infectious Diseases said.
IN OTHER NEWS:
So, what can we do?
Unfortunately, there is no vaccine or treatment for hMPV.
"We currently do not have any vaccine or treatment for hMPV but fortunately most people will recover relatively rapidly without any intervention," director of Infectious Diseases at Mater Health Services Dr Paul Griffin said.
Dr Griffin recommends staying at home if you are unwell, good hand hygiene and wearing a mask.
"The reason why it's important there is awareness regarding this virus at the moment is that it does seem to be on the rise which is not the first time we've seen this but is a little unusual this time of year." he said.