United States: Measles, once thought to be nearly vanquished, is staging a disquieting comeback across continents—from the bustling metropolises of Europe to the stretched landscapes of the Americas. In a jarring comparison, North and South America have witnessed an elevenfold explosion in infections compared to the same stretch last year, while European regions are wrestling with their most pronounced surge in a quarter-century.
As of May 2, 2025, the United States has tallied 935 confirmed infections sweeping through 30 states—a staggering leap from the 285 infections noted in 2024. Canada, similarly beleaguered, is grappling with a spiraling outbreak surpassing 1,000 confirmed cases.
Rebecca Schein, a pediatric infectious disease expert, has lent her insights into this disturbing uptick, raising questions about a disease the US had previously declared eradicated back in 2000.
How Do 2025’s Numbers Stack Up Historically?
From 2000 through 2010, the US rarely breached 100 annual cases, with most clusters confined to vaccine-hesitant communities. Since 2010, sporadic flare-ups crept into the picture, peaking dramatically in 2019 with 1,274 cases, primarily enveloping New York City and suburban New Jersey.
Measles is back.
— The Conversation U.S. (@ConversationUS) May 8, 2025
Cases in the Americas are 11x higher than last year. The U.S. has 935 cases in 30 states as of May 2—up from 285 in all of 2024. A pediatrician warns: unless vaccination rates rise, measles could become a regular, endemic illness again. https://t.co/5BGKwCH0jf
The COVID-19 era saw a drop in cases, thanks to lockdowns and limited travel. However, normalcy brought resurgence, and 2024 witnessed a return to pre-pandemic patterns. Texas currently stands as ground zero for the 2025 outbreak, accounting for 702 infections, with 91 hospitalizations and three recorded deaths—two of whom were children.
Twelve documented outbreaks are blazing across the US this year alone.
A Continental and Global Outbreak
The World Health Organization has issued a high-alert status for the entirety of the Americas. Canada reported a formidable 1,177 cases by April 19, the lion’s share linked to a persistent outbreak in New Brunswick that has now gripped seven provinces. This is a shocking leap from just 12 cases seen across Canada in 2023.
In Mexico, 421 infections have been authenticated, with nearly 400 additional cases undergoing scrutiny. South America isn’t spared: Belize has reported its first cases since 1991, while Brazil and Argentina are seeing sparks of new outbreaks—Buenos Aires being the epicenter in the latter.
Europe isn’t faring any better. The continent reported 35,212 infections in 2024—ten times the previous year’s toll—according to data from the European Centre for Disease Prevention and Control.
How Did the US Eliminate Measles Before?
Measles is nothing short of a viral wildfire—highly communicable, with one carrier able to ignite infections in up to 18 others. For context, influenza’s spread rate hovers around 1 to 4, and COVID-19’s sits at 2 to 5, as per The Conversation.
Declared a notifiable disease in 1912, measles plagued the US with up to 4 million annual cases and 6,000 deaths. Breakthroughs in medical care reduced fatalities, but massive flare-ups persisted every few years.
The tide only turned in 1963, with the arrival of the first vaccine. The MMR shot, shielding against measles, mumps, and rubella, was introduced in 1971. A nationwide campaign in 1977 ensured schoolchildren were immunized, and by 1981, vaccination coverage in grade-schoolers surged to 96 percent.
The 1993 Vaccines for Children initiative further democratized access to immunizations, culminating in measles’s official elimination in the US by 2000.
Why Are Today’s Rising Rates So Dire?
Unlike bacteria, viruses such as measles resist medicinal treatment—prevention via immunization is the only true safeguard. A single vaccine dose shields most individuals, with a booster securing enduring immunity.
To stop the virus from gaining ground, 95 percent of the population must be vaccinated—a threshold known as herd immunity.
But over the past two decades, a slow erosion in vaccination adherence has taken root. The pandemic years deepened this slump as routine medical care fell out of reach for many.
With fewer people vaccinated, measles has found fertile ground once again. Health professionals fear it’s on the verge of regaining a firm, familiar foothold.
What If the Trend Persists?
When a virus remains consistently present in a region, it earns the label of being endemic. Measles, once eradicated, now threatens to join this group, alongside the common cold and COVID-19.
Three or more local cases constitute an outbreak. If these leap across regions, it morphs into an epidemic. Once it transcends borders and oceans, it becomes a pandemic.
Texas’s outbreak began in January 2025 across six counties but swiftly metastasized, affecting 29 counties with over 700 cases by early May, according to The Conversation.
A 2022 algorithm-based projection indicated that without catch-up vaccinations for children skipped during the pandemic, 21 percent of US youngsters—roughly 15 million- may be left defenseless against measles over the next five years. That’s well below the safety threshold.
An April 2025 model warned that measles could once again become a fixture in American life, projecting 850,000 cases over 25 years if current vaccine rates remain unchanged. Should those numbers dip further, the toll could climb to 11 million.
What Can Reverse This Dangerous Climb?
The only way out is forward: communities must reclaim confidence in vaccination. The April 2025 study asserts that a mere 5 percent rise in inoculation rates could slash future case estimates to somewhere between 3,000 and 19,000 over the next quarter-century.
Another study, issued in February, emphasized that swift local health interventions can still curb outbreaks, so long as 85 percent of the populace remains vaccinated.
This requires renewed trust, equal access, and robust public health support to make childhood vaccines both reachable and routine again.