Fungal infections are becoming more common. Why isn’t there a vaccine?

Share

Fungal infections are becoming more common in the United States, but unlike diseases caused by bacteria or viruses, there is no vaccine to protect against the fungal threat.

Fungi cause a wide range of illnesses in people, from the irritating athlete’s foot to life-threatening bloodstream infections..

In the US, fungal infections are responsible for more than 75,000 hospitalizations and nearly 9 million outpatient visits each year, according to the Centers for Disease Control and Prevention. In 2021, around 7,200 people died from fungal diseases. These numbers, the CDC said, are likely underestimates.

a type of fungus candid auris, it can be resistant to all drugs used to treat it and is particularly dangerous for hospitalized and nursing home patients. The fungus was first identified in Japan in 2009 and has since been found in more than 30 countries, including the US. CDC said.

Climate change also threatens to make several infection-causing fungi more widespread: the fungus that causes valley fever thrives in warm, dry soil, and the fungus that causes a disease called histoplasmosis prefers high humidity.

Despite the growing threat, there are currently no licensed vaccines, either in the US or abroad, to prevent fungal infections.

While scientists aren’t concerned that a fungal infection like the one seen on HBO’s «The Last of Us» will wipe out humanity, infections are certainly cause for concern.

«These are the most important infectious diseases you haven’t heard of,» said Karen Norris, an immunologist and vaccine expert at the University of Georgia. «A vaccine has the potential to advance and protect a large number of people.»

fatal fungal infections

Norris said the ultimate goal would be to develop a single vaccine that protects against all fungal infections.

But a «pan-fungal» vaccine is incredibly difficult to make.

That’s because, he said, unlike Covid vaccines, which target a single pathogen, the SARS-CoV-2 virus, a fungal vaccine would ideally protect against the broad spectrum of fungi out there, each biologically different from the next. .

For now, Norris and his team have decided to focus on the three fungi responsible for the vast majority of fatal fungal infections in the US:

  • Aspergillusa common mold that can cause a infection in the lungs and sinuses which can then spread to other parts of the body.
  • candidparticularly candid auris, a type of yeast that can cause serious blood infections, particularly in people in healthcare settings.
  • pneumocystiswhich can cause pneumonia.

In preclinical trials, the experimental vaccine developed by Norris and his team was shown to generate antifungal antibodies in animals, including rhesus macaques. With financial support, researchers could start and finish human vaccine trials within the next five years, she said.

In Arizona, researchers are focused on a vaccine to prevent Valley fever, a lung infection caused by the fungus. coccidioides. The fungus, which is typically found in the hot, dry soils of the Southwest, is an «emerging threat,» Norris said, because climate change is expanding its range.

So far, the vaccine has been shown to be effective in dogs, said John Galgiani, director of the Valley Fever Center of Excellence at the University of Arizona School of Medicine.

Little urgency, lack of funding

While experts know which fungi are best to target, vaccine development has been slow, mainly due to a lack of funding, said Galgiani, who is working to begin a human trial for the valley fever vaccine.

Fungal vaccines are not seen by many in public and private spaces as a «critical unmet need.» he said. Respiratory viruses, such as those that cause covid, flu or measles, infect millions of people and cause thousands of hospitalizations around the world each year, he said. Viruses can be deadly to anyone, anywhere in the world, he said, illustrating the need for vaccines to prevent such diseases.

By comparison, hundreds of species of fungi can cause disease in people, but the most common ones, such as those that infect the skin and nails, or cause vaginal yeast infections or athlete’s foot, are not life-threatening, according to Galgiani. .

Also, serious cases are sporadic in the US, he said.

valley fever, For example, is generally limited to the southern and western parts of the US and is often severe for people with weakened immune systems. Most people inhale Aspergillus every day without getting sick, but it can be life-threatening for people with cystic fibrosis or asthma. candid auris Infections have mostly been confined to healthcare settings and pose the greatest threat to very sick patients.

“As a risk-reward investment proposition, it fails,” Galgiani said of developing a vaccine. «You wouldn’t put your retirement investment into this.» He said it could be eight years before a vaccine against the fungus is available in the US.

But as awareness of the impact of climate change on fungal infections grows, financial support could increase and a fungal vaccine could be developed sooner, Norris said.

In response to growing public health concerns about serious and life-threatening fungal diseases, the National Institutes of Health in September threw a frame about how the US could create a valley fever vaccine in the next 10 years.

Last October, the World Health Organization published its first list of fungi that pose the greatest threat to public health, and called for more research on 19 fungal diseases.

Dr. Andrew Limper, a pulmonologist at the Mayo Clinic in Rochester, Minnesota, said there are several oral treatments for most mild to moderate fungal infections. Depending on the fungus, he said, people may need to take the drugs for three to six months to clear the infection from their system. drugs can come with side effectsincluding headache, stomach ache, vomiting and diarrhea.

People with strong immune systems often recover with medication, but fungal infections, particularly those that affect the lungs, can leave scars, he said.

In severe cases, some people may need to take intravenous medications, such as Amphotericin Bhe said.

Continue NBC HEALTH in Twitter & Facebook.

You may also like...