10 Diseases That Could Make a Comeback in the U.S.

Many diseases that were once rare or eliminated in the U.S. are starting to reappear. Vaccine hesitancy, antibiotic resistance, and climate change are making it easier for old threats to return.

Here are 10 diseases that could make a comeback—and what you need to know about them.

Measles

woman inject a woman on left shoulder — Photo by CDC

Measles was almost wiped out in the U.S., but it’s coming back fast. This highly contagious disease spreads through coughing and sneezing. Unvaccinated children and adults are most at risk. Measles can cause serious complications like pneumonia, brain swelling, and even death.

Polio

Polio was one of the biggest health threats in the 20th century. Thanks to vaccines, it was nearly eliminated in the U.S., but now it’s showing up again. Polio spreads through contaminated water and can cause paralysis. Some people don’t even know they have it until it’s too late.

Tuberculosis (TB)

Tuberculosis used to be called “consumption” because it slowly ate away at people’s health. It spreads through the air and mainly affects the lungs. New drug-resistant strains are making TB harder to treat. Without proper care, TB can be deadly.

Diphtheria

Diphtheria is a rare but dangerous bacterial infection that can block a person’s airways. It spreads through sneezing, coughing, or touching contaminated surfaces. Without treatment, diphtheria can lead to breathing problems, heart failure, or paralysis.

Whooping Cough (Pertussis)

Whooping cough is making a comeback in young kids and teens. This disease causes severe coughing fits that can last for months. Babies are most at risk because their airways are smaller. The vaccine helps, but immunity can wear off over time.

Mumps

A Sick Girl Wiping Her Nose with Tissue — Photo by Andrea Piacquadio

Mumps causes swollen glands, fever, and body aches. It spreads through saliva, making it easy to catch in schools and colleges. While most people recover, mumps can sometimes lead to hearing loss or brain swelling. Outbreaks are becoming more common as vaccine rates decline.

Smallpox (Bioterrorism Threat)

Smallpox was officially eradicated in 1980, but scientists worry it could return. If someone released smallpox as a bioweapon, it could spread quickly. The disease causes fever, body aches, and a deadly rash. The vaccine exists, but most people born after 1972 never got it.

Plague (Bubonic & Pneumonic)

Yes, the plague still exists! It lives in wild rodents in parts of the U.S., especially the Southwest. Bubonic plague can cause swollen lymph nodes and fever. Pneumonic plague, the more deadly form, spreads through the air and can kill within days if untreated.

Yellow Fever

Yellow fever once killed thousands in the U.S., but it’s been gone for over a century. Now, as the climate warms, the mosquitoes that carry it are expanding their range. Yellow fever causes fever, vomiting, and liver damage, sometimes leading to internal bleeding.

Dengue Fever

Dengue fever, also called “breakbone fever,” causes severe joint pain, headaches, and a high fever. It used to be rare in the U.S., but warmer temperatures are bringing dengue-carrying mosquitoes into places like Florida and Texas. Some cases can turn deadly if they cause internal bleeding.