A new federal study suggests life-threatening invasive mold infections may be underrecognized because many patients do not have the traditional risk factors doctors typically associate with the disease.

The study, published Thursday in the Centers for Disease Control and Prevention's "Morbidity and Mortality Weekly Report," analyzed active surveillance data from four Atlanta-area hospitals between 2020 and 2024. Researchers identified 449 cases of invasive mold disease among 968 patients evaluated for possible infection.

Researchers found that 35% of patients with invasive mold disease had none of the classic risk factors used to identify people at high risk, such as certain cancers, organ transplants or prolonged immune suppression. The findings suggest clinicians should also consider the infections in other seriously ill patients, the report said.

Invasive mold diseases are rare infections that primarily affect people with weakened immune systems. They can involve the lungs, sinuses, skin, central nervous system and other organs, and are most commonly caused by aspergillus fungi.

The study found the infections often led to severe illness. About 43% of patients were admitted to an intensive care unit, half required mechanical ventilation and the 90-day mortality rate was 45%. Patients with a current or recent COVID-19 infection had an even higher mortality rate of 66%, compared with 41% for those without COVID-19.

Researchers said the findings could help establish baseline rates for future surveillance and improve recognition of invasive mold disease, which is not a nationally reportable condition. They called for continued surveillance, earlier diagnosis and improved treatments to help reduce deaths from the infections.