Aspergillosis Rising: US Infection Rates Up 5% Annually

Aspergillosis Rising: US Infection Rates Up 5% Annually

March 5, 2026 Nkechi Okonkwo- Health Editor Health

The number of aspergillosis diagnoses in the United States has been steadily increasing, rising by more than 5% annually between 2013 and 2023, according to a recent analysis of electronic health record data. This fungal infection, caused by Aspergillus mold spores commonly found indoors and outdoors, poses a particular threat to individuals with underlying lung conditions or weakened immune systems.

Understanding Aspergillosis and its Rising Prevalence

Aspergillus is a ubiquitous mold, meaning it’s present almost everywhere. For most people, inhaling Aspergillus spores doesn’t cause illness. However, for those with compromised immune systems – such as cancer patients undergoing chemotherapy or organ transplant recipients – or pre-existing lung diseases, the spores can trigger severe and potentially fatal infections. The overall mortality rate associated with aspergillosis is approximately 20%.

The study, published in Open Forum Infectious Diseases, analyzed data from over 76 million US patients across 142 healthcare systems. Researchers identified 20,764 aspergillosis cases during the study period, resulting in a population-based prevalence of 15.26 diagnoses per 100,000 person-years. The increase was observed before the COVID-19 pandemic, peaking in 2022.

Who is Most Vulnerable?

While anyone can be exposed to Aspergillus, certain populations are at significantly higher risk of developing aspergillosis. These include:

  • Individuals with weakened immune systems due to conditions like HIV/AIDS, chemotherapy, or organ transplantation.
  • People with chronic lung diseases such as asthma, cystic fibrosis, or chronic obstructive pulmonary disease (COPD).
  • Those with structural lung abnormalities, like cavities or bronchiectasis.

The study also noted demographic variations, with a higher prevalence observed in males and older adults. Specifically, the prevalence was 37% higher in males compared to females, and significantly elevated in individuals aged 65 and older.

The Challenge of Diagnosis and Surveillance

Currently, there is no centralized surveillance system for aspergillosis in the United States. This lack of comprehensive tracking makes it difficult to fully understand the scope of the problem and to implement targeted prevention strategies. Previous studies have often focused on specific forms of the disease, limited populations (like hospitalized patients), or high-risk groups, providing an incomplete picture of the national trend. The researchers from the University of California, Berkeley, aimed to address this gap by utilizing a large, multi-state electronic health record dataset.

Antifungal Resistance: A Growing Concern

Adding to the complexity of aspergillosis is the increasing resistance of Aspergillus to antifungal medications, particularly azoles. The Centers for Disease Control and Prevention (CDC) highlights this growing threat, noting that Aspergillus fumigatus can develop resistance, making treatment more challenging. Azole antifungals are the primary treatment for aspergillosis, and increasing resistance could lead to higher morbidity and mortality rates. The overuse of azole antifungals in both human and animal medicine, as well as in agriculture, is believed to contribute to this resistance.

Study Limitations and Future Directions

It’s important to acknowledge the limitations of this study. As it relied on electronic health record data, the accuracy of diagnoses depends on proper coding and clinical recognition of the infection. The study also identified cases based on diagnostic codes, which may not capture all instances of aspergillosis. The study is observational, meaning it can demonstrate an association between time and prevalence, but cannot prove causation.

The researchers emphasize the need for improved surveillance systems to better track aspergillosis trends and to identify emerging risk factors. Further research is also needed to understand the mechanisms driving antifungal resistance and to develop novel treatment strategies. The findings from this study can aid in diagnosis and surveillance efforts, but also underscore the importance of considering regional and demographic risk patterns when evaluating patients for potential aspergillosis infection.

What’s Next for Aspergillosis Surveillance?

Public health officials are continually evaluating the need for enhanced surveillance of fungal infections, including aspergillosis. The CDC is actively monitoring antifungal resistance patterns and providing guidance to healthcare professionals on appropriate diagnostic and treatment strategies. Ongoing research efforts are focused on developing more effective antifungal medications and improving diagnostic tools. The data from studies like this one will be crucial in informing future public health interventions and ensuring timely and accurate diagnosis and treatment of aspergillosis.

For more information on aspergillosis, consult the CDC’s Aspergillosis webpage or discuss any concerns with a qualified healthcare provider.