Valley Fever (Coccidioidomycosis) Risk & Prevention

Anyone who lives in or travels to the southwestern United States (Arizona, California, Nevada, New Mexico, Texas, or Utah), or parts of Mexico or Central or South America can get valley fever.  Valley fever can affect people of any age, but it’s most common in adults aged 60 and older. Certain groups of people may be at higher risk for developing the severe forms of valley fever, such as:

• People who have weakened immune systems, for example, people who:
  • Have HIV/AIDS¹
  • Have had an organ transplant ²
  • Are taking medications such as corticosteroids or TNF-inhibitors³
• Pregnant women⁴
• People who have diabetes⁵
• People who are Black^{5, 6} or Filipino⁷

No. The fungus that causes valley fever, Coccidioides, can’t spread from the lungs between people or between people and animals. However, in extremely rare instances, a wound infection with Coccidioides can spread valley fever to someone else,⁸ or the infection can be spread through an organ transplant with an infected organ.⁹

Should I worry about valley fever if I'm traveling to an area where the fungus is common?

The risk of getting valley fever is low when traveling to an area where Coccidioides lives in the environment, such as the southwestern United States, Mexico, or Central or South America. Your risk for infection could increase if you will be in a very dusty setting, but even then the risk is still low. If you have questions about your risk of getting valley fever while traveling, talk to your healthcare provider. You can also consult CDC's Travelers' Health Yellow Book for more information.

Usually not. If you’ve already had valley fever, your immune system will most likely protect you from getting it again. Some people can have the infection come back again (a relapse) after getting better the first time, but this is very rare.

Yes. Pets, particularly dogs, can get valley fever, but it is not contagious between animals and people. Valley fever in dogs is similar to valley fever in humans.¹⁰ Like humans, many dogs that are exposed to Coccidioides never get sick. Dogs that do develop symptoms often have symptoms that include coughing, lack of energy, and weight loss. If you’re concerned about your pet’s risk of getting valley fever or if you think that your pet has valley fever, please talk to a veterinarian.

What should I do if I think I've been exposed to Coccidioides at my workplace or in a laboratory?

If you think you’ve been exposed to Coccidioides at work or in a laboratory, you should contact your Occupational Health, Infection Control, Risk Management, or Safety/Security Department. If your workplace or laboratory doesn’t have these services, you should contact your local city, county, or state health department. Recommendations about what to do in the event of a laboratory exposure have been published.¹¹ There is no evidence showing that antifungal medication (i.e., prophylaxis) prevents people from getting sick with valley fever after a workplace exposure to Coccidioides. If you develop symptoms of valley fever, contact your healthcare provider.

It’s very difficult to avoid breathing in the fungus Coccidioides in areas where it’s common in the environment. People who live in these areas can try to avoid spending time in dusty places as much as possible. People who are at risk for severe valley fever (such as people who have weakened immune systems, pregnant women, people who have diabetes, or people who are Black or Filipino) may be able to lower their chances of developing the infection by trying to avoid breathing in the fungal spores.  

The following are some common-sense methods that may be helpful to avoid getting valley fever. It’s important to know that although these steps are recommended, they haven’t been proven to prevent valley fever.

• Try to avoid areas with a lot of dust like construction or excavation sites. If you can’t avoid these areas, wear an N95 respirator (a type of face mask) while you’re there. Click for more information about respirators.
• Stay inside during dust storms and close your windows.
• Avoid activities that involve close contact to dirt or dust, including yard work, gardening, and digging.
• Use air filtration measures indoors.   
• Clean skin injuries well with soap and water to reduce the chances of developing a skin infection, especially if the wound was exposed to dirt or dust.
• Take preventive antifungal medication if your healthcare provider says you need it.

No. Currently, there is no vaccine to prevent valley fever, but scientists have been trying to make one since the 1960s. Because people who’ve had valley fever are usually protected from getting it again, a vaccine could make the body’s immune system think that it’s already had valley fever, which would likely prevent a person from being able to get the infection.

Scientists have tried several different ways to make a valley fever vaccine. When one version of the vaccine was tested on humans in the 1980s, it didn’t provide good protection, and it also caused people to develop side effects such as swelling at the injection site.¹² Since then, scientists have been looking at ways to make a vaccine with different ingredients that will provide better protection against valley fever and won’t cause side effects. Studies of these new vaccines are ongoing, so it’s possible that a vaccine to prevent valley fever could become available in the future.¹³

• Surveillance. In 19 states, healthcare providers and laboratories are required to report valley fever cases to public health authorities. State health departments collect information about valley fever cases and then send the information to CDC. Disease reporting helps government officials and healthcare providers understand why outbreaks occur and allows them to monitor trends in the number of valley fever cases.
• Raising awareness. CDC, state and local health departments, and other public health agencies work together to educate healthcare providers and the general public about valley fever in order to reduce delays in diagnosis and treatment and improve people’s health outcomes.
• Researching treatment. CDC is assisting other public health agencies with studies to understand the best treatment for valley fever.