America’s Youngest Children Are Unshielded Against Measles — and the Fallout Is Just Beginning

The math is brutal. Infants under 12 months can’t receive the measles, mumps, and rubella vaccine. That means millions of babies in the United States depend entirely on the immunity of the people around them — a shield that is now cracking in ways public health officials haven’t seen in a generation.

As Fortune reported, babies too young for vaccination are essentially defenseless against measles, a virus so contagious that 90% of unvaccinated people exposed to it will become infected. The MMR vaccine’s first dose isn’t administered until a child is 12 to 15 months old. The second dose comes between ages 4 and 6. Until that first shot, an infant’s only protection comes from maternal antibodies — which fade within months — and the vaccination rates of the surrounding community.

Those community rates are falling. Fast.

Nationally, kindergarten vaccination coverage for MMR dropped to 92.7% for the 2023–2024 school year, according to the Centers for Disease Control and Prevention. That’s below the 95% threshold epidemiologists consider necessary for herd immunity against measles. In some counties and school districts, rates have plunged far lower — into the 80s or even 70s. Pockets of vulnerability are no longer pockets. They’re widening into corridors.

The consequences aren’t theoretical. The United States saw 284 confirmed measles cases in 2024 across 17 jurisdictions, the highest annual total since 2019, per CDC data. And 2025 has already outpaced that figure. A significant outbreak in west Texas, centered in Gaines County, has driven case counts sharply upward, with many of the infected being unvaccinated children. As of early April 2025, the CDC has reported hundreds of cases nationally, with clusters appearing in communities where vaccine exemptions have become commonplace.

For infants, the stakes are particularly severe. Measles in babies under 12 months carries a higher risk of complications — pneumonia, encephalitis, and in rare cases, subacute sclerosing panencephalitis, a fatal degenerative disease that can emerge years after the initial infection. These aren’t marginal risks. Measles kills approximately 1 to 3 of every 1,000 infected children in developed countries. In infants and immunocompromised individuals, the fatality rate is higher.

The erosion of vaccine confidence didn’t happen overnight. It’s the product of more than two decades of misinformation, beginning with Andrew Wakefield’s now-retracted 1998 study falsely linking the MMR vaccine to autism. That paper was discredited and Wakefield lost his medical license, but the damage metastasized. Social media amplified the message. Algorithms rewarded outrage and fear over data and nuance. And a loosely organized but politically effective anti-vaccine movement found footholds in state legislatures, school boards, and eventually the White House.

Robert F. Kennedy Jr.’s appointment as Secretary of Health and Human Services in January 2025 marked a turning point. Kennedy, who spent years as one of America’s most prominent vaccine skeptics, has publicly questioned the safety of the MMR vaccine and promoted debunked theories about vaccines and autism. His confirmation sent shockwaves through the public health establishment. Career scientists at the CDC, FDA, and NIH have described an atmosphere of uncertainty and self-censorship, according to reporting by The New York Times.

The federal government’s messaging on vaccines has grown muddled. Where previous administrations — Republican and Democratic alike — spoke with one voice about the safety and efficacy of childhood immunizations, the current HHS leadership has introduced ambiguity. Kennedy has stopped short of calling for an end to vaccine mandates outright, but his public statements have emboldened state-level efforts to expand exemptions. And his department has redirected funding away from vaccine promotion campaigns.

This matters because trust, once lost, is extraordinarily difficult to rebuild.

Pediatricians across the country are reporting a shift in parental attitudes. Dr. Sean O’Leary, a pediatric infectious disease specialist at the University of Colorado and chair of the American Academy of Pediatrics’ Committee on Infectious Diseases, told Fortune that he’s seeing more parents delay or refuse vaccines entirely — not just for philosophical reasons, but because they genuinely don’t know what to believe anymore. The information environment has become so polluted that even well-educated, well-intentioned parents struggle to distinguish evidence from propaganda.

The Texas outbreak illustrates the pattern with painful clarity. Gaines County, a rural area in the Permian Basin, had kindergarten MMR vaccination rates well below 80% when the outbreak began. Many families belonged to religious communities that discouraged vaccination. When measles arrived — likely imported by a traveler — it spread with the ruthless efficiency the virus is known for. Children too young to be vaccinated were among the first infected. Several were hospitalized. At least one infant required intensive care, according to Texas Department of State Health Services reports covered by The Texas Tribune.

But this isn’t just a Texas problem. Or a red-state problem. Or a rural problem.

Vaccine hesitancy has become bipartisan and geographically diverse. Affluent enclaves in California, Oregon, and New York have some of the lowest vaccination rates in the country. Waldorf schools, certain private academies, and homeschool networks have become hotspots of non-vaccination. The reasons vary — some parents cite religious beliefs, others express concerns about ingredients or side effects, and a growing number simply distrust institutions. The pandemic accelerated all of these trends. COVID-19 vaccine mandates and the politicization of public health created a backlash that spilled over into attitudes toward all vaccines, including those with decades of safety data behind them.

The irony is staggering. The MMR vaccine is one of the most thoroughly studied medical interventions in history. Two doses are approximately 97% effective at preventing measles. The vaccine has been in use since 1971. Hundreds of millions of doses have been administered worldwide. Its safety profile is well-established, with serious adverse events occurring at a rate of roughly one per million doses. By any rational measure, it is one of modern medicine’s greatest achievements.

And yet here we are.

The World Health Organization declared measles eliminated in the United States in 2000, meaning sustained transmission had been interrupted. That status has come under threat repeatedly in recent years. If current trends continue — declining vaccination rates, increasing exemptions, weakened federal leadership on immunization — the U.S. could lose its elimination status. WHO has already flagged the country as at risk.

For parents of newborns, the calculus is terrifying. A mother who was vaccinated or previously infected passes antibodies to her infant through the placenta, providing temporary protection. But those maternal antibodies wane, typically by 6 to 9 months of age. After that, the baby is exposed. There’s a window of several months — from roughly 6 months to 12 or 15 months — during which a child has no meaningful protection against measles unless the community around them is sufficiently vaccinated. In outbreak settings, the CDC recommends an early dose of MMR as young as 6 months, but this dose doesn’t count toward the routine series and may be less effective because maternal antibodies can interfere with the immune response.

So parents are left hoping. Hoping their neighbors vaccinated their kids. Hoping the daycare checks records. Hoping the person coughing in the pediatrician’s waiting room doesn’t have measles. Hoping isn’t a public health strategy.

The economic dimensions are significant too. A single measles case in the United States triggers an expensive public health response — contact tracing, quarantine, laboratory testing, healthcare costs. The CDC has estimated that a single outbreak can cost local health departments hundreds of thousands to millions of dollars. The 2019 outbreak in New York City, which involved 649 cases concentrated in Orthodox Jewish communities in Brooklyn and Queens, cost the city an estimated $8.4 million in direct response costs alone. Scale that to a national resurgence and the figures become staggering.

Hospitals are already strained. Emergency departments, still dealing with the aftereffects of pandemic-era staffing shortages, are poorly positioned to handle a surge of measles cases requiring isolation rooms and specialized care. Measles patients must be placed in negative-pressure rooms to prevent airborne transmission — the same rooms used for tuberculosis patients. Many community hospitals have only a handful of such rooms. A significant outbreak could overwhelm capacity quickly.

There’s also the question of what happens to other vulnerable populations. Immunocompromised individuals — cancer patients undergoing chemotherapy, organ transplant recipients on anti-rejection drugs, people with HIV — cannot receive live vaccines like MMR. They depend on herd immunity just as infants do. As vaccination rates decline, these individuals face increasing risk. It’s not an abstraction. It’s a grandmother undergoing breast cancer treatment. A toddler with leukemia. A teenager who received a kidney transplant.

Some states are pushing back. California, which tightened its vaccine exemption laws after a 2015 Disneyland-linked outbreak, has maintained relatively high overall vaccination rates, though pockets of resistance persist. New York strengthened its laws after the 2019 outbreak, eliminating religious exemptions for school-required vaccines. But other states have moved in the opposite direction. Several legislatures considered or passed bills in 2024 and 2025 expanding personal belief exemptions or prohibiting schools from requiring vaccination records, according to tracking by the National Conference of State Legislatures.

The federal government’s role has traditionally been to set the floor — funding the Vaccines for Children program, which provides free vaccines to uninsured and underinsured kids, and supporting CDC surveillance and outbreak response. That infrastructure remains in place but faces budget pressures and political headwinds. The Biden administration’s final budget proposal included increased funding for immunization programs. The current administration’s budget outline, released in March 2025, proposed cuts to the CDC’s immunization budget, though Congress has not yet acted on those proposals.

Meanwhile, misinformation continues to circulate at scale. On X, formerly Twitter, anti-vaccine accounts with hundreds of thousands of followers regularly post misleading claims about MMR safety. Some cite the Vaccine Adverse Event Reporting System, a passive surveillance database that anyone can submit reports to and that explicitly warns its data cannot be used to establish causation, as evidence of widespread vaccine harm. These posts generate millions of impressions. Platform moderation has been minimal since Elon Musk’s acquisition of Twitter in 2022, and the current political environment has made content moderation on health topics even less likely.

The scientific community hasn’t been silent. The American Academy of Pediatrics, the Infectious Diseases Society of America, and the American Medical Association have all issued statements in recent months reaffirming the safety and necessity of childhood vaccines. Individual physicians have taken to social media to counter misinformation, often at personal cost — facing harassment, threats, and coordinated attacks from anti-vaccine activists.

But statements and social media posts can only do so much against a well-funded, emotionally resonant movement that exploits parental anxiety and institutional distrust. The anti-vaccine movement understands something that public health officials have been slow to grasp: facts alone don’t change minds. Stories do. Fear does. And the movement has an endless supply of both.

What would a genuine measles resurgence look like in the United States? Before the vaccine was introduced in 1963, the country saw 3 to 4 million cases annually, with approximately 48,000 hospitalizations, 1,000 cases of encephalitis, and 400 to 500 deaths per year. Nobody is predicting a return to those numbers — vaccination rates, while declining, remain far above pre-vaccine levels. But the trajectory is concerning. Each percentage point drop in coverage creates exponentially more opportunities for the virus to find susceptible hosts. And measles, with a basic reproduction number of 12 to 18, is among the most transmissible infectious diseases known to science.

The babies can’t wait. They can’t advocate for themselves. They can’t choose to be vaccinated early. They are, as Fortune put it, sitting ducks — dependent on a social contract that an increasing number of Americans are opting out of.

The question facing the country isn’t whether measles will continue to spread. It will. The question is whether the political will exists to reverse the decline in vaccination rates before the outbreaks become large enough to kill children who never had a chance to be protected. That’s not a public health question. It’s a moral one. And right now, the answer is far from clear.