Recent reports of a passenger with measles aboard an Amtrak train traveling through Penn Station on its way to Washington, D.C., evoked scenes from pandemic thrillers like Contagion. The idea of one infected individual unknowingly spreading disease to countless others might seem dramatic—but in today’s highly interconnected world, it’s an increasingly realistic scenario.
Not long ago, such an event would have barely raised concern. In 2000, the United States declared measles eliminated, thanks to a highly effective vaccine introduced in 1963. With about 95% of the population immunized, herd immunity protected even those who couldn’t receive the vaccine. But in recent years, vaccination rates have declined in certain regions, allowing this once conquered virus to regain a foothold.
Troubling data
The consequences are already being felt. As of April 17, there have been 800 confirmed measles cases across 25 U.S. states—more than double last year’s total. Out of 800 patients, 85 patients were hospitalized and 47 patients who were hospitalized are under age 5. Three patients have died (the first measles-related deaths in the US in a decade).
Texas has been hit hardest, with 597 reported cases and two fatalities. The outbreak began in Gaines County, home to a sizable Mennonite population that often forgoes modern medicine, including vaccines. Although childhood vaccines are required for school attendance in Texas, exemptions are allowed for various reasons, including religious beliefs. According to The New York Times, only 82% of kindergarteners in Gaines County have received the MMR (measles, mumps, rubella) vaccine—far below the 95% threshold needed for herd immunity. Nearly all cases in Texas involve individuals known to be unvaccinated.
New York City has seen similar warning signs. While relatively small outbreaks occurred in 2013 (58 cases) and 2014 (25 cases), a major surge in Brooklyn in 2018 led to 649 cases by mid-2019. The outbreak, concentrated in the Williamsburg neighborhood, primarily affected unvaccinated children under 18. Twenty patients required intensive care. A citywide push to increase vaccination raised the rate of children with at least one MMR dose from 79.5% to 91.1%, but the effort cost the city $8.4 million.
Vaccine resistance fueling outbreaks
Since 2021, however, vaccine resistance—initially focused on COVID-19—has expanded to include vaccines more broadly. This shift has contributed to declining MMR coverage nationwide. According to the Centers for Disease Control and Prevention, MMR vaccination rates among kindergarteners dropped from 95.2% in the 2019–20 school year to 92.7% in 2023–24. That drop has left approximately 280,000 students at risk.
We need to remember just how easily and quickly measles spreads among the unvaccinated. The virus is airborne and highly contagious—it can be transmitted simply by breathing the same air as an infected person, even hours after they’ve left the area. Individuals are contagious for four days before and four days after the appearance of the signature rash. Most current patients are under 20, with children under five—many of whom are too young to be fully vaccinated—particularly vulnerable to severe complications.
Not a ‘normal’ illness
Seung Hee Kang, an infectious disease physician at The Floating Hospital, stressed the importance of remembering how deadly measles was before the vaccine era: “Before 1963, measles infected virtually every child in the U.S. and killed more than 12,000 people in 1900 alone,” she noted.
“Though often dismissed as a ‘normal’ childhood illness, measles brought fever, rash, and serious complications like pneumonia, blindness, and encephalitis (brain swelling).” The measles mortality rate varied by age group but could reach as high as 10%.
“There are countless accounts of personal tragedy due to measles in that era,” Dr. Kang added. “One that stood out to me recently came from The Atlantic, which referenced a harrowing scene from Jacob Riis’s How the Other Half Lives, describing the disease’s toll on families in 19th-century New York City slums: ‘Listen! That short hacking cough, that tiny, helpless wail—what do they mean? … The child is dying with measles. With half a chance it might have lived; but it had none.’ ”
The best defense
“What vaccines have achieved over the past 60 years is stunning,” she said. “I often share a CDC graph showing how measles cases plummeted after the vaccine was introduced. It’s a testament to science and public health.”
Experts unanimously agree that immunization is the best defense. Two doses of the MMR vaccine are more than 97% effective at preventing measles. The CDC recommends the first dose at 12–15 months of age and the second at 4–6 years. With global measles activity on the rise, declining U.S. vaccination rates, and ongoing international travel, health officials warn that what once felt like a disease of the past is now a real and growing threat.
“Measles is not a benign virus,” Dr. Kang concluded. “History, science, and current outbreaks all point to the same conclusion: vaccination isn’t just protection for the individual—it’s protection for the entire community.”
