It is the fifth reported case of the serious bacterial infection in the region this year.

Public health physician Dr Craig Dalton expressed the HNELHD's condolences.

"This is a tragic event and our sympathies are with the woman's family at this very difficult time," he said.

NSW Health is urging people to be alert to lesser known signs of meningococcal disease with 22 cases already reported in 2019 - and the peak period for the disease still more than a month away.

Dr Dalton said cases normally start to increase towards the end of flu season when people's immune systems are weaker from viruses.

"Meningococcal disease is a rare but serious bacterial infection that can cause death within hours," he explained.

"It's hard to identify, so the more symptoms people know about, the better.

"Often it can mimic other common illnesses, so be aware nearer spring that nausea symptoms, vomiting, neck stiffness, joint pain, light sensitivity, or a sudden fever, could be something else.

"Most people normally associate meningococcal disease with a rash of red-purple spots or bruises but in some cases a rash doesn't appear, or it could be the last symptom to take shape."

Meningococcal infection does not spread easily.

It is spread by secretions from the nose and throat of a person who is carrying the bacteria.

Close and prolonged contact is needed to pass it on.

"It more commonly occurs in people aged between 15 and 24 years as they tend to be involved in more intimate social activities such as kissing, and children aged under the age of five, but it can affect anyone," Dr Dalton said.

Vaccination is the best means of protection against meningococcal disease.

Vaccination for meningococcal disease types A, C, W and Y, is available on the National Immunisation Program for infants at 12 months of age and adolescents in Year 10.

Any adolescents aged 15 to 19 years who miss the vaccine in school are eligible for a free vaccine from their GP.

However, as there are several strains of meningococcal disease, and vaccination does not cover all strains, even vaccinated people need to be on the lookout for symptoms.

The latest Annual Immunisation Report shows vaccination rates in NSW are at their highest level ever, with close to 95 per cent of five-year-olds fully vaccinated.