The United States has reached a troubling new milestone, recording the highest number of measles cases in more than three decades. As of July 7, 2025, according to the Johns Hopkins Measles tracker, a total of 1,281 confirmed measles cases have been reported in the United States. This surpasses the 1,274 cases reported in all of 2019, the last recent peak following an outbreak in several orthodox Jewish communities in suburban New York City.

The figure, by all accounts, represents an underestimation of the actual incidence of measles infection. Measles was officially declared eliminated in the US in 2000, and since then the country typically saw an average of about 180 cases, almost all linked to travel to other countries where measles was still encountered.

This alarming resurgence is primarily driven by falling childhood vaccination, particularly in under-vaccinated communities, as seen in a significant outbreak originating in West Texas. The vast majority of those affected, approximately 95 percent of confirmed cases in 2025, have been individuals who were unvaccinated or whose vaccination status was unknown.

The consequences have been severe, with three measles-related deaths reported in the US this year—two children in Texas and one adult in New Mexico, all of whom were unvaccinated—matching the total number of US measles deaths over the previous two-and-a-half decades. Experts warn that if current trends persist, the US is at risk of losing its measles elimination status.

While West Texas has been identified as a major epicenter of the current measles surge, accounting for 69 percent of reported cases in an outbreak spanning Texas, New Mexico, and Oklahoma, the prevalence of measles is alarmingly widespread across the United States.

As of July 5, 2025, at least 38 states have reported at least one case of measles this year, with a total of 27 identified outbreaks (defined as three or more related cases). Cases have appeared in various states, including Alaska, Arkansas, Arizona, California, Colorado, Florida, Georgia, Hawaii, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maryland, Michigan, Minnesota, Missouri, Montana, Nebraska, New Jersey, New Mexico, New York, North Dakota, Ohio, Oklahoma, Oregon, Pennsylvania, Rhode Island, South Dakota, Tennessee, Texas, Utah, Vermont, Virginia and Washington.

This widespread distribution shows that while some outbreaks stem from imported cases, local transmission is largely responsible for most reported cases. For instance, a recent spike in Colorado cases was linked to an infectious traveler on a plane, leading to further community spread.

The broad age range of affected individuals also suggests that this outbreak has been developing over years due to persistent gaps in measles vaccine coverage, predominantly the result of an insidious anti-vaccination and disinformation campaign that has taken a disturbing hold on the national and international theater.

The concerning resurgence of measles is directly linked to a decline in childhood vaccination rates across the US. A recent study published in JAMA (Journal of the American Medical Association) analyzed county-level vaccination data and found that childhood MMR (measles, mumps and rubella) vaccination rates have been declining in much of the US since the start of the COVID-19 pandemic.

Specifically, among 2,066 counties in 33 states, 78 percent reported a decline in vaccination rates. The county-level mean vaccination rate decreased from nearly 94 percent before the pandemic to about 91 percent after the pandemic. This puts the national average well below the 95 percent threshold public health experts consider necessary for herd immunity against measles, a target the US has missed for four consecutive years.

Notable drops include Hawaii, which saw its vaccination rate plummet from around 95 percent pre-pandemic to roughly 80 percent in the most recent estimates, and Wisconsin, which recorded the lowest average rate among studied states, in the 70s.

The connection between declining vaccination rates and the increase in measles infections is evident. Most confirmed measles cases in the US this year—approximately 95 percent to 96 percent—have occurred in individuals who were unvaccinated or whose vaccination status was unknown. This underscores the critical role of vaccination in preventing the disease.

Measles is one of the most highly transmissible infectious diseases, making even a small drop in immunity a significant risk factor for large outbreaks. Its basic reproduction number is estimated at 12, meaning one infected person can transmit it to up to 12 others in a fully susceptible population. Without a high percentage of vaccinated individuals, the virus can spread rapidly, leading to the return of diseases once eliminated. Experts warn that if current vaccination trends persist, measles may become endemic in the US within approximately two decades, giving up all the gains made in the public health effort to eliminate it.

The troubling trend of surging measles cases is not unique to the United States, as neighboring countries Canada and Mexico are also grappling with significant and deadly outbreaks. The Pan American Health Organization (PAHO) and World Health Organization (WHO) have highlighted these developments, warning that the “overall risk of measles in the Americas Region is considered high” due to low vaccination rates.

As of mid-June 2025, the Americas Region has confirmed 7,132 measles cases and 13 deaths. This marks a 29-fold increase compared to the 244 cases reported in the same period of 2024. Canada, Mexico, and the United States account for most of these cases. The most affected age groups across the region are among children under 5 and adolescents aged 10 to 19 years. A significant proportion of cases in the Americas (56 percent) were in unvaccinated individuals, with 35 percent having unknown or absent vaccination status. Globally, as of June 6, 2025, WHO reported 88,853 confirmed measles cases in 168 member states.

Mexico has reported 2,597 confirmed measles cases, including nine deaths, as of the week ending June 24, 2025. As of late May, Mexico had reported at least 1,520 cases. This marks Mexico’s worst measles outbreak in decades. The outbreak began in March and was traced to an 8-year-old unvaccinated Mennonite boy who visited relatives in Seminole, Texas, an epicenter of the US outbreak. Cases then rapidly spread through Chihuahua’s Mennonite community via schools and churches, then to workers in orchards and cheese plants.

The Mennonite community in Chihuahua has historically low vaccination rates due to misinformation about vaccines and deep-seated distrust of authorities. Some members view vaccination as a matter of “freedom of expression” and prefer “to cure themselves in their own way,” with some even intentionally exposing children at “measles parties.”

Canada has reported 3,170 measles cases (including confirmed and probable cases) and one death as of epidemiological week 23, 2025. This far exceeds the 177 cases reported in all of 2024 and constitutes the highest annual number of cases since measles elimination was achieved in 1998. The reported death was an infant born prematurely with a congenital measles infection from an unvaccinated mother. Most cases (93 percent) in 2025 were exposed within Canada. A multi-jurisdictional outbreak affecting unvaccinated individuals in communities with low coverage began in New Brunswick in October 2024 and has spread to nine provinces and territories.

While significant shares of outbreaks in the US, Canada, and Mexico have been concentrated in closely connected Mennonite communities with historically low vaccination rates, PAHO experts have not formally linked outbreaks in the three countries genetically due to limited genetic sequencing. However, travel links have been identified, such as cases in Colorado being linked to travel to Chihuahua, Mexico, and Canadian outbreaks linked to cases in Michigan, underscoring the essential point that viruses and disease do not respect borders, meaning a threat in one place is a threat to the entire world’s population. And given the highly safe and effective vaccine, such developments are a disturbing and expanding trend.

The troubling resurgence of measles and other vaccine-preventable diseases in the Americas is being further inflamed by deliberate political actions taken by Health and Human Services (HHS) Secretary Robert F. Kennedy Jr. and his chosen appointees. These maneuvers are widely perceived by scientific and medical communities as fostering deep mistrust in vaccines and posing a direct threat to the bedrock of childhood vaccination programs.

It should be recalled that on June 9, 2025, Kennedy abruptly dismissed all 17 members of the CDC’s Advisory Committee on Immunization Practices (ACIP), an unprecedented move in the committee’s 61-year history that bypassed standard CDC procedures. He falsely justified the purge by claiming ACIP was “plagued with persistent conflicts of interest” and was a “rubber stamp.” Former CDC director, Dr. Tom Frieden, called these claims “total misrepresentation” and “classic misinformation,” noting that a 2009 report cited by Kennedy found administrative errors but not widespread conflicts of interest. Then, just two days later, Kennedy appointed eight new ACIP members, many of whom are known for publicly expressing vaccine skepticism, promoting misinformation, or opposing established public health practices.

During the recent two-day meeting, chair of the ACIP and one of the authors of the Great Barrington Declaration, Martin Kulldorff, announced new working groups to “evaluate the cumulative effect of the recommended vaccine schedule.” This move was criticized by Dr. Sean O’Leary of the American Academy of Pediatrics (AAP) as an “anti-vaccine trope.”

The committee’s agenda also shifted to include revisiting “long-settled questions” such as the safety of thimerosal, a mercury-based preservative that has been scientifically debunked as having any link to autism. This echoes long-standing anti-vaccine narratives, even though most US vaccines have been thimerosal-free since 2001. In no uncertain terms, these comments and actions are an open attack on the entire public health edifice.

Additionally, the withdrawal of a US funding pledge to Gavi, the Vaccine Alliance, an international organization that immunizes children in the world’s poorest countries, further compounds this crisis. The US was a major funder, and this withdrawal of $1.2 billion could lead to over 1 million preventable child deaths within five years by disrupting immunization programs for 75 million children. Public health experts warn that these “destabilizing decisions, made without clear rationale, may roll back the achievements of US immunization policy, impact people’s access to lifesaving vaccines, and ultimately put US families at risk of dangerous and preventable illnesses.”

The resurgence of vaccine-preventable diseases like measles and whooping cough is directly linked to these actions and the declining trust and vaccine uptake they foster. Modeling indicates that if current vaccination rates persist, measles may become endemic again in the US within two decades, and a 10 percent decline in MMR vaccination could lead to 11.1 million measles cases over 25 years.