Why Measles, Mumps and Whooping Cough Are Making a Comeback
Jake Newby
| 4 min read
Jake Newby is a brand journalist for Blue Cross Blue...
Key Takeaways
- Declining vaccination rates have created immunity gaps, allowing contagious diseases like measles and pertussis to resurge across vulnerable communities.
- High vaccination coverage supports herd immunity and immunocompromised people while limiting disease spread during outbreaks and reducing risks.
- Measles remains exceptionally contagious, spreading through lingering airborne particles and signaling population immunity weaknesses when outbreaks occur in under-vaccinated communities and regions.
- Routine childhood immunizations prevent outbreaks, save lives and help protect communities from preventable diseases through sustained coverage.
Diseases like measles, mumps and whooping cough may feel like illnesses from another era to most people. Decades of high childhood vaccination rates rendered these once-common infections rare, leading to generations of Americans growing up without ever seeing a case firsthand.
But according to public health experts, that’s changing in 2026.
Recent outbreaks of measles and whooping cough (Pertussis) in the United States – along with concerns about declining polio vaccination rates and poliovirus detections in parts of Europe –serve as reminders that vaccine-preventable diseases can return when immunity declines.
Continuing the progress made over the last half-century revolves around prevention and maintaining high vaccination rates across the country.
Why are certain diseases returning?
Vaccines don't eliminate viruses from existence — they prevent them from spreading.
When enough people in a community are vaccinated, diseases struggle to find new hosts. This concept is called herd immunity, according to the World Health Organization (WHO), and it protects vulnerable populations, such as infants, older adults and people with weakened immune systems who may not be able to receive certain vaccines.
However, vaccination rates have declined in many places since the COVID-19 pandemic because of disruptions to routine healthcare, increased vaccine hesitancy, misinformation and reduced access to preventive care. Even relatively small declines in vaccination rates can create pockets of under-vaccinated people where contagious diseases can spread rapidly.
A JAMA study determined that if childhood vaccination rates continue to decline, diseases previously eliminated in the U.S. — including measles, rubella and even polio — could eventually threaten the general population again. The researchers concluded that maintaining or increasing vaccination coverage is critical to preventing future outbreaks.
Measles are one of the most contagious viruses
Among vaccine-preventable diseases, measles is especially concerning because it spreads so easily. The virus can linger in the air for up to two hours after an infected person leaves a room, according to the U.S. Centers for Disease Control and Prevention (CDC), and one infected individual can spread it to most unvaccinated people nearby. Measles can cause pneumonia, brain swelling, hearing loss and in rare cases, death.
Although measles was declared eliminated in the U.S. in 2000, outbreaks have increased in recent years, largely in communities with lower vaccination rates. Measles often serves as an early warning sign that immunity gaps are developing within a population because it spreads so efficiently, per WHO.
Mumps and whooping cough are also resurging
Cases of mumps continue to occur in schools, colleges and other close-contact settings, per the CDC, even though outbreaks are generally much smaller than they were before widespread vaccination.
Meanwhile, whooping cough has also resurged in many countries, according to research, including the U.S. The bacterial infection causes severe coughing fits that can last for weeks and is particularly dangerous for infants, who are at the highest risk for hospitalization and death. Whooping cough comes from pertussis, and the pertussis vaccine is commonly coupled with tetanus and diphtheria vaccines.
In 2025, WHO reported that declining childhood vaccination coverage across Europe and Central Asia has contributed to renewed outbreaks of both measles and whooping cough, highlighting how quickly vaccine-preventable diseases can rebound when immunization rates decline.
Polio is not currently considered a budding problem in the U.S.. However, in recent years, vaccine-derived poliovirus has been detected through wastewater surveillance in several European countries, prompting health officials to emphasize the importance of maintaining high vaccination coverage. While these detections do not mean widespread polio transmission has returned, they demonstrate that the virus can still circulate where immunity gaps exist.
Why disease prevention is so important
The good news is these diseases remain largely preventable. Routine childhood vaccinations have saved millions of lives worldwide and continue to be among the safest and most effective public health tools available. Global immunization prevents millions of deaths each year, according to WHO, but millions of children still miss recommended vaccines annually, leaving communities vulnerable to outbreaks.
If you have questions about your family's vaccination schedule or aren't sure whether you're up to date on recommended vaccines, talk with your primary care provider. Staying current on immunizations not only protects individuals but also helps safeguard infants, older adults and others who rely on strong community immunity to stay healthy.
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