The United States is grappling with a sharp rise in measles cases, with nearly 900 infections confirmed across 10 states as of late April 2025. Health officials warn this marks one of the largest resurgences of the highly contagious virus in recent years, raising concerns about slipping vaccination rates and global travel-linked spread. Measles, once declared eliminated in the U.S. in 2000, has made a troubling comeback, highlighting gaps in community immunity and the dangers of vaccine misinformation.
What Is Measles, and Why Is It Spreading Now?
Measles is a viral infection spread through airborne droplets when an infected person coughs or sneezes. The virus can linger in the air for up to two hours, making it one of the most contagious diseases known—far more transmissible than flu or COVID-19. Symptoms typically begin with a high fever, cough, runny nose, and red, watery eyes, followed by a distinct red rash that spreads from the face downward. Complications range from ear infections and pneumonia to severe brain swelling, which can be fatal, particularly in children under 5 and immunocompromised individuals.
The current surge is largely tied to two factors: declining vaccination rates and international travel. The CDC notes that over 90% of recent cases involve unvaccinated individuals or those with unknown vaccination status. “When vaccination coverage drops below 95%, communities lose the ‘herd immunity’ needed to stop outbreaks,” explains Dr. Amanda Rivera, an epidemiologist at the Johns Hopkins Bloomberg School of Public Health. “We’re now seeing pockets of vulnerability where measles can ignite quickly.”
Outbreak Hotspots and Contributing Factors
As of April 2025, active outbreaks have been reported in Florida, Arizona, Ohio, Minnesota, Washington, and five other states. Florida’s Broward County accounts for nearly 20% of national cases, linked to a single unvaccinated traveler who returned from a country with ongoing measles transmission. In Ohio, a daycare center outbreak infected 32 children, most under age 2 and too young for full vaccination.
Vaccine hesitancy continues to play a role. While the measles-mumps-rubella (MMR) vaccine is 97% effective after two doses, CDC data shows national MMR coverage among kindergarteners fell to 93% in 2023—the lowest in a decade. Some communities report rates as low as 80%, driven by misinformation about vaccine safety and religious or philosophical exemptions. “The false link between vaccines and autism has been debunked for decades, but its legacy persists,” says Dr. Rivera. “Social media algorithms amplify fear, not facts.”
Global travel further fuels risks. Measles remains common in parts of Africa, Asia, and the Middle East. Unvaccinated travelers can bring the virus back, sparking outbreaks in under-protected communities. In 2025, over 60% of U.S. cases were tied to international travel, compared to 40% in pre-pandemic years.
The Critical Role of the MMR Vaccine
The MMR vaccine, introduced in 1971, is the safest and most effective way to prevent measles. Two doses provide lifelong immunity for most people. Before the vaccine, measles caused 3–4 million U.S. cases annually, including 400–500 deaths. By 2000, widespread vaccination reduced domestic transmission to near zero.
Recent CDC modeling estimates the current U.S. vaccination rate prevents 94 million infections and 1.3 million deaths over 20 years. Still, gaps remain. Approximately 250,000 kindergarteners are unvaccinated for measles yearly, per 2024 data. “Vaccines are victims of their own success,” says Dr. Paul Offit, director of the Vaccine Education Center at Children’s Hospital of Philadelphia. “Many parents have never seen measles, so they underestimate its severity.”
Recognizing Symptoms and Seeking Care
Early measles symptoms mimic a cold or flu: high fever (up to 104°F), cough, and nasal congestion. After 2–3 days, tiny white spots (Koplik spots) may appear inside the mouth. The hallmark red rash develops 3–5 days after symptoms begin, starting as flat red spots on the face and spreading to the torso and limbs.
Infected individuals can spread the virus for four days before and after the rash appears. There is no specific antiviral treatment, so care focuses on rest, hydration, and managing complications. High-risk patients, such as infants or pregnant women, may receive immune globulin to reduce severity.
Protecting Vulnerable Populations
Measles poses disproportionate risks to certain groups. Children under 5 are more likely to suffer severe complications, including pneumonia (1 in 20 cases) and encephalitis (1 in 1,000 cases). Pregnant women face higher risks of premature birth or low birth weight. Immunocompromised individuals, such as chemotherapy patients, cannot safely receive live vaccines like MMR, relying solely on community immunity for protection.
In outbreak areas, health departments recommend infants as young as 6 months receive an early MMR dose if traveling internationally. For others, the first dose is typically given at 12–15 months, with a booster at 4–6 years. Adults unsure of their vaccination status can request a blood test to check immunity or receive a booster.
Addressing Misinformation and Building Trust
Public health agencies are battling vaccine misinformation through targeted campaigns. The CDC’s “Join the Fight” initiative partners with schools and community leaders to share survivor stories and factual data. In Minnesota, where a 2023 outbreak infected 85 people, clinics now host “vaccine talk” workshops to address parental concerns.
“Trusted messengers matter,” says Dr. Maya Krishnan, a pediatrician in Phoenix. “When a parent hears about measles from their child’s doctor instead of a Facebook post, they’re more likely to vaccinate.” Some states, like New York and California, have tightened vaccine exemption policies for school enrollment, though debates over personal choice versus public health continue.
What’s Next for U.S. Measles Control?
Ending the current outbreaks requires a multi-pronged approach: boosting vaccination rates, rapid outbreak response, and global cooperation. The CDC advises unvaccinated individuals to avoid travel to outbreak regions and quarantine for 21 days after exposure. Schools and daycares in hotspot areas are urged to review student vaccine records and exclude unvaccinated children during outbreaks.
Globally, measles cases rose 18% from 2021 to 2024, with deaths up 43%, per the World Health Organization. Low-income countries, where vaccine access remains uneven, account for 95% of fatalities. The U.S. has pledged $75 million to Gavi, the Vaccine Alliance, to support measles campaigns in 15 high-risk nations.
For now, experts stress vigilance. “Measles is a preventable tragedy,” says Dr. Offit. “Every case represents a missed opportunity to protect someone.” With schools reopening and summer travel rising, health departments nationwide are ramping up vaccine clinics and public outreach to curb the virus’s spread before it escalates further.