March 29, 2023 – Infection with the fungus Candida auris could be problematic for some and fatal for others, especially people who find themselves at higher risk due to their age or weakened immune system (immunosuppression). A vaccine under development may offer hope.
The fundamental problem shouldn't be necessarily the fungus itself, but the shortage of treatment options. C. auris is immune to two of the three fundamental categories of antifungal therapies, and in some cases to all three.
“It's the only truly multidrug-resistant fungus we have,” said Dr. Ashraf Ibrahim, a researcher on the Lundquist Institute in Torrance, California. He can also be lead writer of a new study Evaluating how well Vitalex Biosciences' monoclonal antibody vaccine might work in stopping or treating these infections.
Although relatively rare, C. auris Infections could cause death in 30 to 70 percent of individuals at higher risk, said Ibrahim, founding father of Vitalex and an infectious disease physician at Harbor-UCLA Medical Center.
“So you don’t need a scientist to explain to you how dangerous this thing is.”
The CDC describes C. auris as “acute threat to public health.” C. auris The infection spreads mainly in healthcare facilities. The fungus is not airborne – so you cannot get it by sneezing or coughing. However, it can survive on surfaces and on human skin.
If the vaccine continues to show promising results, it could one day be used to boost immune protection in older people entering a nursing home, people receiving multiple antibiotics in hospital, and people likely to require intensive care after a medical procedure.
Safest at the moment
Health authorities want to increase surveillance for C. auris infections, Ibrahim said. Right now, people with healthy immune systems are not at higher risk unless they become susceptible at some point. “If you may have any form of immunosuppression, it really takes advantage of that and starts to grow rather a lot – after which starts to invade.”
The vaccine could kill C. auris fungi when combined in laboratory experiments. The vaccine also reduced the production of a “biofilm” by 30 to 40%. A fungal biofilm is a barrier that can prevent antifungal drugs from entering an infected cell or organ.
In experiments with mice with C. auris infection, for example, the vaccine reduced fungi in the kidneys and heart by tenfold. This means that there may be some protection against systemic bloodstream infections with C. auris, said the researchers.
Not the only mushroom in the family
One could assume that the monoclonal antibody vaccine directly against C. aurisHowever, this is not the case. Scientists are developing the vaccine with Candida albicansa common fungus that is responsible for the majority of yeast infections in healthy women.
So why C. albicans“We are actually working on both right now, but we are trying to get the vaccine to patients as quickly as possible,” Ibrahim said.
C. auris Infections have only been detected relatively recently, compared to C. albicanswhich has been known for decades. Vitalex already had a program to develop a dual-antigen vaccine against C. albicans. When comparing the two fungi, they found that they share certain cell surface proteins that can be targeted to prevent the two fungi from attaching to and invading body cells.
“We said, ‘Well, we have the dual antigen vaccine in hand. Why don’t we just try it in Candida auris and see if it protects?'” Ibrahim said. “And it is clear that the vaccine actually works very well with Candida auris.”
A possible role in treatment
The vaccine can not only prevent infections, but can also be used in combination with other antifungals in people who are already infected. C. aurisIn studies of an earlier version of the vaccine, there was a combined positive effect when the mice were vaccinated and additionally treated with an antifungal drug, Ibrahim said.
“It's pretty very similar to COVID-19,” Ibrahim said. “If the vaccine doesn't prevent the disease, an extra treatment option can actually save the person from dying.”
The next step will be a toxicity study on rabbits to assess the vaccine's safety. This could be followed by clinical trials on humans.
It is still early
“Candida auris is a major problem for a really specific population,” said Aaron Glatt, MD, chief of the Division of Infectious Diseases at Mount Sinai South Nassau in New York, when asked for comment. “For the overwhelming majority of the population, this shouldn't be an issue straight away. But as public health officials and as infectious disease experts, we've got to be very concerned about everyone,”
“Further spread of this disease would certainly put more people at potential risk,” Glatt added.
Glatt urged caution in interpreting preliminary results like this one. “It's a really serious public health issue … but it surely's not something that everybody within the United States must be eager about on a regular basis straight away.”