Splendour in the Grass revellers has been urged to be on the lookout for symptoms of meningococcal after a man who attended the festival died from the disease.
A man in his 40s from Sydney died from the illness, and NSW Health was only made aware on Thursday after his death.
Another reveller at the festival has fallen ill with meningococcal, leading authorities to issue a state-wide warning.
"We are urging people who attended the event in the North Byron Parklands on July 21 – 24 to be alert to the symptoms of meningococcal disease and act immediately if they appear," NSW Health said in a statement.
"Although the disease is uncommon, it can be severe."
As many as 50,000 people attended Splendour in the Grass each day, although the festival's first day was largely rained-off after a massive downpour turned the site into a quagmire.
NSW Health's Dr Jeremy McAnulty said the early intervention of the disease could be lifesaving.
"Onset of meningococcal disease symptoms can appear suddenly and become very serious very quickly. If you suspect meningococcal disease, don't wait for the rash – see a doctor immediately," McAnulty said.
According to health experts, meningococcal bacteria are carried by about 10 per cent of the population harmlessly at the back of the throat or nose.
They are then spread via droplets expelled during coughing and sneezing, or close contact such as kissing.
If the infection is detected early enough and the correct antibiotics are administered, most cases make a full recovery.
"While it is a well-known symptom of meningococcal disease, the rash does not always occur, or may present late in the illness," McAnulty added.
Multiple cases of invasive meningococcal diseases have been reported in Australia this year. In July, a two-year-old child died after contracting a case. The four most common meningococcal types in Australia are B, C, W and Y, and vaccines are available to protect against them.
A total of 12 cases were reported in South Australia in 2021 – of which six were serogroup B and six were serogroup W.
There were three deaths from meningococcal disease in 2021.
Symptoms of meningococcal include:
• Red and purple rash
• Severe and unexplained limb pain
• Difficulty waking up
• High-pitched crying in babies
• Severe headache
• Upset by bright lights
• Stiff neck.