No vaccines for fungal infections are currently approved for use in humans. As of 2025, not a single fungal vaccine has received FDA approval, placing fungi far behind viruses and bacteria in the vaccine landscape. This gap is striking given that fungal infections kill an estimated 2.5 million people each year worldwide, with another 1.3 million deaths partly attributable to fungal disease. Several promising candidates are in development, though, and the first human clinical trials for a Valley fever vaccine are on the horizon.
Why Fungal Vaccines Are So Hard to Make
The core problem is biology. Fungi are eukaryotes, meaning their cells are built much like human cells. They share genes and molecular machinery with us, which makes it difficult to find targets a vaccine could attack without also provoking a harmful immune response against the body’s own tissues. Viruses and bacteria are structurally far more foreign, giving vaccine designers clearer targets.
Fungi also shapeshift. Many disease-causing species can switch between completely different physical forms depending on their environment, and each form comes with a different set of surface proteins. Histoplasma and Blastomyces, for example, grow as mold in soil but transform into yeast once they enter the warmth of a human body. Coccidioides, the fungus behind Valley fever, converts into large structures called spherules that resist the immune system’s attempts to engulf them. Candida species can flip between yeast, hyphal, and pseudohyphal forms in response to changes in pH or nutrients.
These shifts aren’t cosmetic. Each new form activates a distinct genetic program that remodels the fungal cell wall, changing the very molecules a vaccine would need to recognize. A vaccine designed to target one stage of the lifecycle may be useless against another. This “moving target” problem is one of the biggest reasons fungal vaccine development has lagged decades behind other infectious diseases.
The Scale of the Problem
Fungal infections are far deadlier than most people realize. A 2024 analysis published in The Lancet estimated 6.5 million cases of invasive fungal infection per year globally. Invasive aspergillosis alone, which often strikes people with lung disease or weakened immune systems, accounts for over 1.8 million deaths annually. Candida bloodstream infections kill roughly 995,000 people each year. Cryptococcal meningitis, common in people with advanced HIV, has a 76% fatality rate.
The people most vulnerable are those with compromised immune systems: organ and stem cell transplant recipients, cancer patients undergoing chemotherapy, people living with HIV, and anyone on long-term immunosuppressive medications. These groups are the primary target populations for fungal vaccine development, since they face both the highest risk of infection and the worst outcomes.
Valley Fever Vaccine: Closest to Reality
The most advanced fungal vaccine effort centers on Valley fever (coccidioidomycosis), a lung infection caused by inhaling fungal spores common in the southwestern United States and parts of Latin America. Researchers at the University of Arizona’s Valley Fever Center for Excellence have been working on this problem for over 40 years.
Their biggest breakthrough came from dogs, which are even more susceptible to Valley fever than humans. A study showed that two doses of a vaccine, with a booster 28 days after the first shot, provided high levels of protection in dogs. The manufacturer, Anivive Life Sciences, has started the registration process with the USDA’s Center for Veterinary Biologics, which could make it the first approved vaccine against any systemic fungal disease in any species.
The canine success is now being translated to humans. The National Institute of Allergy and Infectious Diseases awarded a contract with first-year funding of $4.8 million and up to $33 million total to adapt the dog vaccine for people. That money will cover manufacturing, safety testing, and support for a Phase 1 human clinical trial. Researchers involved in the project have said there’s no biological reason the canine vaccine couldn’t also work in humans, since the immune mechanisms are similar across species.
Candida Vaccine Candidates
Candida species cause infections ranging from common yeast infections to life-threatening bloodstream infections in hospitalized patients. The most clinically advanced vaccine candidate is called NDV-3A, which targets a protein that Candida albicans uses to stick to human tissues and form biofilms on medical devices like catheters.
NDV-3A completed an early-phase clinical trial in patients with a history of recurrent vulvovaginal candidiasis. A single intramuscular dose was safe, well-tolerated, and triggered a strong immune response. Blood samples from patients who responded to the vaccine could block Candida from adhering to surfaces, forming biofilms, and invading vaginal cells in lab tests. In mouse studies, the vaccine also prevented Candida from colonizing central venous catheters and spreading to the kidneys. These are encouraging results, but the vaccine has not yet entered large-scale efficacy trials in humans.
Aspergillus and Broad-Spectrum Approaches
Aspergillus fumigatus is one of the most common fungal killers, particularly dangerous for people whose immune systems are suppressed. Vaccine research has identified a protein called Asp f 3 that, when used as a vaccine in mice, protects against invasive aspergillosis. The vaccine appears to work by activating immune cells that restore the fungus-killing ability of macrophages (a type of white blood cell) even when those cells have been weakened by immunosuppressive drugs. Researchers have also engineered modified versions of the protein that retain their protective effect while removing the portion that could trigger allergic reactions in humans.
Beyond species-specific vaccines, some research groups are pursuing a broader goal: a pan-fungal vaccine that could protect against multiple fungal species at once. This approach exploits the fact that many pathogenic fungi share certain cell wall components, particularly sugar-based molecules like beta-glucans and chitin. Experimental formulations using particles enriched with these shared molecules have shown promise in mouse models, stimulating immune responses effective against several different fungi. If successful, a pan-fungal vaccine could simplify protection for high-risk patients who face threats from multiple fungal species simultaneously.
What’s Holding Things Up
Even with promising candidates, fungal vaccines face practical hurdles beyond the biology. The populations most in need of protection, immunocompromised patients, are also the hardest to vaccinate effectively because their immune systems may not mount a strong enough response. Vaccine developers have to figure out the right timing, dosing, and immune-boosting additives to make vaccines work in people whose immune defenses are already weakened.
Funding has historically been another barrier. Fungal infections disproportionately affect people in low-income settings or those already burdened by other diseases like HIV, which has made them less attractive to pharmaceutical investment compared to more visible infectious diseases. The recent NIH commitment to Valley fever research signals a shift, but the overall investment in antifungal vaccine development remains small relative to the death toll.
The most realistic timeline for a human fungal vaccine puts a Valley fever vaccine in Phase 1 trials within the next few years, with broader availability still years beyond that. Candida and Aspergillus vaccines are further behind, still working through preclinical and early clinical stages. For now, prevention of fungal infections relies on antifungal medications, environmental precautions, and managing the underlying conditions that put people at risk.