One in 11 people have been infected with the disease, according to blood sampling in regional NSW.
Two Australian states have announced they are expanding free access to Japanese encephalitis vaccine as the annual mosquito season approaches.
The news follows the release of results of a seroprevalence survey undertaken by NSW Health, which showed evidence of previous Japanese encephalitis was detected in one in 11 people.
NSW Chief Health Officer Dr Kerry Chant said more than 1000 participants from communities known to have Japanese encephalitis virus activity across Griffith, Temora, Corowa, Balranald and Dubbo had provided blood samples for the seroprevalence survey.
Eighty in 917 people showed antibodies that indicated a past infection that would not have been acquired in another country, she revealed.
The aim of the survey was to understand the risk infection in NSW, so 131 participants were excluded for having received a vaccine, travelled for more than one month in, or were born in, a country where the virus is commonly found.
âThe results of this serosurvey provide us with valuable insight into the prevalence of past JE infections in these communities after it was first detected earlier this year,â Dr Chant said.
âVaccination is an important part of the public health response but, currently, global supply of JE vaccine is very limited. So weâre urging people to protect themselves by avoiding mosquito bites altogether, particularly as we head into warmer months.â
Japanese encephalitis can be a serious and even fatal disease, however only around 1% of people infected with the virus will experience symptoms, according to NSW Health.
As of 8 September, 13 people in NSW have been clinically diagnosed this year and two of those have died. All were estimated to have acquired the virus between mid-January and the end of February 2022.
NSW has now expanded free access to the vaccine to residents living in affected regional areas to protect those most at risk.
This will be made available through the GPs, however patients are being urged to make a specific appointment with their doctor to ensure the vaccine is available.
The Japanese encephalitis vaccine has been available to people who work with pigs or mosquitoes or in specialised laboratories, Communicable Diseases Network Australiaâs national priority groups and some international travellers.
But now it is also recommended for some people who live or work in high-risk NSW Local Government Areas (LGAs).
These include people who are aged 50 years or older and spend significant time outdoors (a minimum of four hours a day) and live in Albury, Balranald, Berrigan, Carrathool, Dubbo Regional, Edward River, Federation, Goulburn Mulwaree, Greater Hume, Griffith, Lockhart, Murray River, Temora and Wentworth.
NSW Health said in a statement that Japanese encephalitis vaccine was available through local GPs.
âPeople who meet the above criteria should make an appointment with their GP and let them know it is for the JE vaccine,â the statement said.
âGPs may require a few daysâ notice so they can order the vaccine.â
Victoriaâs Department of Health has followed suit in expanding free access to the vaccine in a bid to protect people who live in areas of risk from a possible re-emergence of the virus in the warmer months.
The newly expanded criteria includes anyone who lives or usually works in the LGAs Campaspe, Gannawarra, Greater Shepparton, Indigo, Loddon, Mildura, Moira, Swan Hill, Wodonga and Towong, and who are aged 50 years and over and spend at least four hours per day outdoors â whether for work or recreation.
People in Towong Shire, along with people aged 50 years and over and those who are spending several hours outdoors for any reason in all of these areas are also included in the expanded criteria.
Victoriaâs Deputy Chief Health Officer Associate Professor Deborah Friedman said the vaccine was available free for people who meet these criteria, from select GPs, local public health units, including some covid vaccination hubs, community pharmacies and local councils.
âThis expansion means even more people can access the vaccine ahead of the warmer months to protect themselves,â she said.
The Department of Health, in collaboration with the Ovens Murray, Goulburn Valley and Loddon Mallee local public health units, is currently conducting a serosurvey for Japanese encephalitis, to better understand the spread of this virus in northern Victoria and risk factors for infection.
âGetting vaccinated is one important step people can take, along with simple actions like wearing long, loose-fitting clothing outdoors, using mosquito repellents containing picaridin or DEET on all exposed skin, and limiting outdoor activity if lots of mosquitoes are about,â Associate Professor Friedman said.
As of 8 September, national disease surveillance reporting shows Victoria has recorded nine cases of clinically confirmed Japanese encephalitis and three probable cases where the person has been linked epidemiologically and/or has symptoms of the disease and has laboratory suggestive evidence. There has been one death.
Meanwhile, Queensland had two confirmed or probable cases, South Australia had nine, Queensland had five and the Northern Territory had one. There have been two deaths in South Australia and one in Queensland, official records show.
On March 4 this year, Australiaâs Acting Chief Medical Officer, Dr Sonya Bennett, declared Japanese encephalitis a communicable disease incident of national significance and established a national working group of communicable disease, vaccine and arbovirus experts. It is now a nationally notifiable disease in humans and animals.
The disease is spread to humans by infected mosquitoes, however it is not passed from person to person. Humans also cannot get infected with the virus by touching an infected animal or eating animal products.
The Medical Republic has contacted health departments in South Australia, Queensland and the Northern Territory to get an update on any changes to Japanese encephalitis vaccine access. More information about the national alert is available here.
