Why Are Infectious Diseases Are Rising Again

Liam Saranich | News Editor

As of spring 2025, the United States is seeing a rise in infectious diseases that were once well-controlled. Diseases like measles and whooping cough are coming back, and other threats like tuberculosis and dengue may also make an appearance. These increases are not random. They are a result of changes in vaccination habits, public health systems, and people’s behaviors after the COVID-19 pandemic.

Measles, once eliminated in the United States in 2000, has returned. Nearly 900 cases have been reported this year across 30 states. Texas has been hit the hardest, with over 600 of these cases, including several hundred from just one county. Other states, including Indiana, Michigan, Ohio, and Pennsylvania, have also reported outbreaks. What makes this alarming is that two previously healthy children have died from measles in recent months, and many others have been hospitalized. The return of measles is due to a drop in vaccination rates. During the pandemic, less families visited doctors, and some missed routine shots. At the same time, misinformation about vaccines has spread quickly online, leading some parents to delay or refuse vaccination for their children. This created gaps, opening the door for highly contagious diseases like measles to spread.

Whooping cough, or pertussis, is another disease that is increasing. As of April 2025, more than 8,000 cases have been reported in the United States, double the number from this time last year. Whooping cough is especially dangerous for babies and young children. Several infants have already died this year from the disease. Before COVID-19, vaccination rates helped keep this illness down. But during the pandemic, with people wearing masks and staying home, the number of cases dropped. Now, as people have returned to normal life and fewer children are getting their full set of vaccines, the disease is spreading again. Another reason is that the pertussis vaccine loses its strength over time, so adults need booster shots. Many people do not realize this, making themselves and others at risk.

There is an outbreak of tuberculosis in Kansas. Although it is not as contagious as measles or whooping cough, it can be very serious and is spread through the air. Kansas has reported dozens of active TB cases in just a few months. TB is concerning in close living situations, like shelters, long-term care facilities, or places where people live in tight quarters. The source of this outbreak has not been fully identified, but health officials are trying to test and treat everyone at risk to keep it from spreading.

Another infectious disease on the radar is dengue fever. This mosquito-borne virus is common in tropical areas but is now being reported in parts of the United States, especially in southern states where the climate is warmer. The CDC has issued a warning asking doctors to be alert for dengue, especially in patients with recent travel to areas where it is common. With warmer temperatures and more frequent travel, diseases like dengue have a better chance of being contracted even in places where they were never a concern.

Behind all of these increasing threats is a bigger issue which is the weakening public health defenses. During the COVID-19 pandemic, many public health systems were stretched to their limits. Some local health departments have lost funding or staff. Fewer resources mean slower responses to outbreaks and less public education on vaccines and disease prevention. At the same time, vaccine hesitancy has increased. Some people are more hesitant of vaccines than they were before the pandemic. Social media and misinformation have played a large part in this, making it harder for real health information to reach families.

Health experts warn that unless communities work together to rebuild trust in vaccines and strengthen public health systems, these kinds of outbreaks will continue. Vaccines remain one of the best tools we have to prevent the spread of dangerous diseases. Encouraging routine check-ups, improving access to healthcare, and providing clear information can all help the country return to stronger protection against infectious threats.