NSW Health has issued a new alert following the confirmation of two additional measles cases in Sydney, including one with no identified source of infection, raising concerns that the virus is circulating undetected in the community.
There have now been 26 measles cases confirmed in NSW since 1 January 2026, according to official figures. The second of the two most recent cases is particularly concerning because the person has had no known contact with any other confirmed measles patient and did not visit any of the publicly listed exposure locations from earlier in the outbreak.
What the data shows is a measles situation that has shifted from a series of imported cases into potential community transmission. The initial case came from an international traveller from South-East Asia who visited Sydney Airport and Blacktown Hospital while infectious in late December, and while that case is no longer actively spreading, it demonstrates how quickly the virus reaches the community. Now, nearly three months later, authorities cannot trace the source of the most recent infection, which suggests others may have been exposed without knowing it.
Measles is among the world's most contagious diseases, spread by contact with infected nasal or throat secretions through coughing or sneezing, and the virus remains active and contagious in the air or on infected surfaces for up to two hours; one person infected by measles can generate up to 18 secondary infections. The most recent case recently visited Nepean Hospital emergency department on 9 March while unknowingly infectious, meaning the virus could have spread to staff and patients in a high-traffic healthcare setting.
NSW Health Director of Communicable Diseases Dr Christine Selvey outlined the symptoms to monitor: fever, sore eyes, a runny nose and cough, usually followed three to four days later by a red, blotchy rash spreading from the head and face down the body. People who visited the exposure locations listed on the NSW Health website are being advised to monitor for symptoms for up to 18 days and to call ahead to their doctor if symptoms develop.
What matters most in slowing measles now is vaccination coverage. In Australia, two doses of measles vaccine offers 99% protection against illness and serious complications. However, this protection only works at scale. Measles needs a coverage rate of about 92% to 94% to prevent spread, and Australia's national aspirational coverage target is 95%.
The problem is that Australia is falling short. Coverage rates for all children at one year of age decreased to 91.54% compared to the four quarters to June 2025, meaning the nation is below the herd immunity threshold. For the second dose of MMR-containing vaccine at 24 months of age, only 11.5% of Statistical Area Level 3 areas in Australia achieved coverage above the 95% target. This means most regions in the country are vulnerable to measles spread.
The decline has been marked. In 2023, there continued to be modest but concerning declines in vaccination coverage among children in Australia relative to pre-COVID-19 pandemic peaks, with factors likely including a combination of acceptance issues and access issues such as difficulty organising appointments. Post-COVID, the number of fully vaccinated one-year-olds has dropped as low as 80 per cent in some parts of the country.
The clinical significance is stark. Measles infections are particularly severe in very young children, pregnant women, and those with weakened immune systems. These groups cannot be protected by vaccination alone and instead rely on sufficient community immunity to prevent exposure.
Free MMR vaccines are available in NSW for anyone born after 1965 who hasn't had two doses of the vaccine or is unsure of their vaccination status. The measles vaccine can prevent the disease even after exposure if given early enough, which is why people who believe they have been exposed are encouraged to seek vaccination immediately.
Pregnant women, immunocompromised people, or those with an infant exposed within the past six days should contact their local Public Health Unit on 1300 066 055. More information and a full list of exposure locations is available on the NSW Health website. For general queries about measles or symptoms, people can call their GP or Healthdirect on 1800 022 222.