A vaccine developed by University of Georgia researchers successfully protects against and treats vaginal yeast infections in mice, according to a newly published study.
This is the newest application of the vaccine, which was previously shown to protect against the three most common fungal pathogens in four preclinical animal models, including nonhuman primates. These three fungi are responsible for more than 80% of fatal fungal infections.
The latest finding helps clear the way for the vaccine to enter clinical trials. If successful, the vaccine will be the first to prevent pathogenic fungal infections, which the World Health Organization considers one of the top threats to public health.
We can't just keep … trying to make new drugs to fight fungal infections because we're going to lose." -Karen Norris, College of Veterinary Medicine
"The thing that's keeping researchers like me up at night is increasing antifungal drug resistance," said Karen Norris, lead author of the study and a professor of immunology and translational biomedicine in the UGA College of Veterinary Medicine. Norris is also the CEO and founder of NXT Biologics, the company behind the vaccine. "It's not a prediction. We're living it right now.
"And we can't just keep swinging away and trying to make new drugs to fight fungal infections because we're going to lose. These organisms are always adapting to resist new drugs."
The vaccine, named NXT-2, aims to fill that gap, preventing fungal infections before they happen and reducing the need for antifungal medications by doing so.
First clinical trial to target yeast infections; later trials to focus on life-threatening infections
The vaccine will first be tested in women with recurrent yeast infections, also known as recurrent vulvovaginal candidiasis or RVVC.
Caused by a type of candida fungus, the condition affects hundreds of millions of women globally. It also costs billions of dollars in health care visits, medication and lost productivity each year in the U.S. alone.
"RVVC is not life-threatening, but it is miserable," Norris said. As many as one in 10 women develop the condition during their lifetime, suffering three or more yeast infections per year. "This is a huge need."
The current treatment protocol relies on one class of drug, increasing the likelihood that the medication will develop resistance and be harder to treat going forward. They also can't be used during pregnancy and don't prevent future infections.
I believe this vaccine will do the most good in people who are at high risk for highly dangerous, life-threatening infections." -Karen Norris
Most of the women suffering from recurrent yeast infections are young and otherwise healthy, which makes them an ideal population for a Phase 1 clinical trial.
The results will inform future trials in more vulnerable patient populations, such as transplant recipients and cancer patients, two groups that are particularly vulnerable to life-threatening fungal infections, also covered by the vaccine.
"I've had a physician say to me, 'I have patients that I get through stem cell transplants for their cancer treatment, and then they get aspergillosis. I often don't have adequate treatment for that,'" Norris said. Pulmonary aspergillosis is a serious complication of this treatment and up to half those patients will die from the infection.
"That's where I believe this vaccine will do the most good: in people who are at high risk for highly dangerous, life-threatening infections."
Fungal infections: A growing public health threat
Fungal infections are most commonly seen in people with immune disorders, including those with uncontrolled HIV or impaired immunity from therapies like chemotherapy or anti-inflammatories.
But previous research from Norris, postdoctoral fellow Emily Rayens and the College of Public Health's José Cordero showed that the at-risk population has expanded in recent years.
That study showed people with diabetes; chronic obstructive pulmonary disease (or COPD); or co-infections such as COVID-19, tuberculosis or flu are likewise at higher risk of developing fungal infections.
As drug resistance grows and infections become more difficult to treat, prevention becomes more critical, Norris said.
This is the first fungal vaccine that has shown broad, cross-protective antifungal immunity in multiple animal models, which bodes well for future clinical trials.
Published in Nature's NPJ Vaccines, the study was co-authored by the UGA Center for Vaccines and Immunology's Daniel Wychrij, Taylor Chapman, Whitney Rabacal, Hubertine Willems and Kwadwo Oworae. Additional co-authors include Emily Rayens, a doctoral graduate from UGA's Department of Infectious Diseases, and Brian Peters of the University of Tennessee.
