A Vaccine Against Valley Fever Finally Works—for Dogs

An experimental vaccine that could protect millions of people living in the American Southwest from valley fever —an infection caused by a soil-dwelling fungus that is difficult to treat and can cause disability and death—has passed its first test of efficacy and is moving toward federal approval, possibly within two years.

The catch: The vaccine was tested in, and will be developed for, dogs. A formula that could be given to humans, if it can be achieved, lies many years and millions of dollars down the road. But researchers say even this first step is notable, a significant milestone on the way to preventing potentially hundreds of thousands of human cases a year.

To be clear, this vaccine is needed for dogs, too. They aren’t just a model system for lab work; for reasons that are not well understood, they develop the disease and its most severe manifestations at higher rates than humans do. Possibly 30 million dogs live in the area endemic for valley fever, which centers on Arizona, stretches from California to West Texas, and reaches into Nevada and Utah. In some Arizona counties, 1 in 10 dogs develops the disease each year, and it is the No. 1 cause of dogs being surrendered to animal control. A vaccine that could protect them would save loved pets from suffering and reduce the costs borne by owners and shelters.The vaccine candidate, which was developed by the Valley Fever Center for Excellence at the University of Arizona College of Medicine, uses a version of one of the fungi responsible for the infection, from which a gene that controls virulence has been deleted. Working with researchers at other universities and biotech startup Anivive Lifesciences of Long Beach, California, the team inoculated dogs with a solution containing live spores from the altered fungus. They found a two-dose regimen of an initial shot and a booster was safe and protected dogs against developing disease when they were exposed to wild fungus in the lab. The results were published ahead of October inclusion in the journal Vaccine.“We think the results are very convincing that the vaccine shows robust protection in this model—and it’s an aggressive model, compared to wild-type infection,” says John Galgiani, senior author on the paper and director of the University of Arizona center. The group is working now on scaling up the small-batch prototype developed in his lab to produce a shelf-stable formula that could be commercialized for use in dogs. The team will then submit it to the US Department of Agriculture, which regulates animal vaccines, for conditional approval. They hope to see it distributed by 2023.It’s the first good news in a long trail of disappointments that stretches back to the 1980s, when Galgiani was part of a thinly funded research group investigating a human vaccine candidate based on inactivated fungus. The trial was unsuccessful—the injection-site reactions were too painful—and from then on, there has been no vaccine for valley fever, nor for any fungal disease.