A new vaccine targeting the three most common human fungal infections is showing promising results in early preclinical studies. The data paves the way for future human trials testing this pan-fungal vaccine in the hopes of preventing infections that have been linked to over one million deaths a year.
On HBO's new series The Last of Us, we're introduced to a world that has been decimated by a fungal pandemic. Succinctly explained in the very first moments of the premiere episode, fungi generally cannot survive in warm human body temperatures. In the fictional world of the series a certain type of mind-controlling fungus evolves to thrive in our warm bodies, triggering a zombie hellscape of infected humans.
There is, however, real science behind this horrifying fiction. And while it is true that the vast majority of fungi cannot survive at human body temperatures, there are a number of fungal species that thrive in the warmth of our bodies.
Trillions of micro-organisms live inside each of us. This is known as our microbiome. The vast majority of these microbes are bacteria but plenty of other things can also be found, including parasites and viruses.
About a decade ago researchers discovered a thriving population of fungi also reside within the human body. Dubbed the mycobiome, several dozen types of fungi have been found to symbiotically live inside of us, and most are relatively harmless. But some are not our friends, particularly when we are immunocompromised.
It's estimated about 1.6 million people die every year globally from invasive fungal infections. In 2022 the World Health Organization released its first ever list of "fungal priority pathogens," citing fungi as an emerging serious public health threat. There are limited anti-fungal medications, and increasing rates of fungal resistance to these crucial drugs.
“There’s a significant unmet clinical need for this kind of prevention and also treatment, particularly among immunocompromised individuals,” said Karen Norris, lead investigator on the new study. “The patient population at risk for invasive fungal infections has increased significantly over the last several years.”
Three specific genera of fungus account for the vast majority of deadly fungal infections in humans – Aspergillus, Candida, and Pneumocystis. So researchers set out to develop a recombinant peptide vaccine that targets those three primary pathogens.
A new study published in the journal PNAS Nexus is reporting on the efficacy of this experimental vaccine in several animal models. The study revealed the vaccine, dubbed NXT-2, effectively induced broad, cross-reactive antibody responses in all animal models. The vaccine also reduced morbidity and mortality in immunosuppressed animals exposed to the three key pathogenic fungi.
“Because it targets three different pathogens, the vaccine has the potential to be groundbreaking regarding invasive fungal infections,” said Norris.
It's early days for the research, and a little more work to establish optimal formulations and doses will be necessary before preliminary human testing can begin. But the need for these kinds of fungal therapies is clear.
Justin Beardsley, an infectious disease research from the University of Sydney, worked with the WHO on developing its Fungal Priority Pathogen list in 2022. He said tackling current and emerging fungal pathogens is a crucial research priority that has long been ignored.
“Fungi are the ‘forgotten’ infectious disease," Beardsley said late last year. "They cause devastating illnesses but have been neglected so long that we barely understand the size of the problem."
The new study was published in PNAS Nexus.
Source: University of Georgia