What is Aspergillus fungus? Two dead, four seriously ill as fungal infection cluster engulfs major Sydney hospital, authorities launch probe; all you need to know

At least two people died and four others fell seriously ill after contracting fungal infections while at Sydney's Royal Prince Alfred (RPA) Hospital in 2025, according to reports. Sydney Local Health District (SLHD) has launched an investigation into a cluster of fungal infections at a major Sydney hospital transplant unit.

Six patients in the transplant ward of the RPA hospital developed infections between October and December in 2025, according to ABC Australia and 9News. Two subsequently died with the infection, an SLHD spokesperson said. The spokesperson further informed that Aspergillus fungus was a common mould that occurred in many environments, including building sites.

Hospital redevelopment can be reason behind fungal outbreaks

Amid the investigation, SLHD acknowledged that the $940 million redevelopment at the hospital could be the reason behind the possible fungal outbreak, according to 9News. The construction on the project has been ongoing since 2023.

"Aspergillus is a common mould found in soil, plants, dust and damp environments," the statement said, ABC Australia and 9News reported. "People inhale Aspergillus spores every day without becoming unwell; however, it can pose a risk to certain groups, particularly those with weakened immune systems," the statement added.

Ward was closed during probe

The ward was closed during the investigation. Transplant patients were relocated, and potentially at-risk patients were contacted, according to 9News. According to ABC Australia, an advisory panel held by NSW Chief Health Officer Kerry Chant permitted the ward to reopen on February 9, 2026.

The spokesperson said patients at risk of exposure to the infection were relocated from the ward while investigations were carried out. A deep clean, upgraded air filtration and air quality testing were carried out. "Remedial works were completed, and no elevated levels of Aspergillus in the transplant ward were detected," they said, as quoted by ABC Australia.

What is Aspergillus fungus?

Aspergillosis is an infection caused by breathing in spores of Aspergillus, a common mould, according to the Centers for Disease Control and Prevention (CDC). It is the primary national public health agency of the United States, operating under the Department of Health and Human Services (HHS). According to the CDC, most people do not get sick from Aspergillus. It can, however, cause mild to severe illness in certain populations, such as people with weakened immune systems or lung diseases.

Aspergillus causes different types of infections, including chronic lung conditions and widespread infections. Symptoms can be mild to severe. People with weakened immune systems or lung diseases are at greatest risk for symptoms. Symptoms range from mild to life-threatening.

Cough and shortness of breath are common symptoms among all types of aspergillosis. Some types of infections cause nasal congestion, headache, fatigue, and coughing up blood.