A leading immunologist has raised alarm over a troubling phenomenon: a “post-herd-immunity world.” This warning comes in the wake of significant measles outbreaks affecting communities with low vaccination rates across the American south-west, as well as parts of Mexico and Canada. The United States is currently grappling with its largest measles outbreak in a quarter-century, with the epicenter located in west Texas.
The ongoing measles outbreak has tragically resulted in the deaths of two unvaccinated children and one adult, and has spread to neighboring states, including New Mexico and Oklahoma. Dr. Paul Offit, an expert in infectious disease and immunology who directs the Vaccine Education Center at the Children’s Hospital of Philadelphia, stated, “We’re living in a post-herd-immunity world. I think the measles outbreak proves that.” He further emphasized the contagious nature of measles, noting, “Measles is the most contagious of the vaccine-preventable diseases, the most contagious human disease really – it is the first to come back.”
Measles was declared eliminated in the U.S. in 2000, but this status is at risk of being lost if there are 12 months of sustained transmission of the virus. As of May 1, the U.S. Centers for Disease Control and Prevention (CDC) reported 935 confirmed measles cases across 30 jurisdictions. Alarmingly, nearly one in three children under five years old involved in the outbreak, totaling 285 young children, have been hospitalized.
Three major outbreaks in Canada, Mexico, and the U.S. now account for the overwhelming majority of approximately 2,300 measles cases reported in the World Health Organization’s six-country Americas region. The risk of measles is considered high across the Americas, with cases increasing elevenfold compared to 2024. Meanwhile, data from the European Centre for Disease Prevention and Control (ECDC) and WHO indicates that measles cases in Europe have surged tenfold in 2024 compared to the previous year. Notably, of the 35,212 reported cases in Europe for 2024, 87% were in Romania.
The ECDC highlighted that the drop in vaccination rates has contributed significantly to the recent spike in measles cases. Only three countries—Hungary, Malta, and Portugal—have achieved vaccination coverage of 95% or more for both doses of the measles vaccine. Leticia Ruíz, the director of prevention and disease control in Chihuahua, Mexico, noted that many cases are occurring in areas with tight-knit Mennonite communities that have a history of migration through the American south-west, Mexico, and Canada.
While Mennonite teachings do not explicitly prohibit immunization, there is a reluctance to assimilate into broader society, which may limit their contact with public health authorities and result in lower vaccination rates. Experts are concerned that as misinformation spreads, the rate of infection for vaccine-preventable diseases like measles will continue to rise.
Compounding the issue, U.S. health secretary Robert F. Kennedy Jr. has been criticized for spreading misleading claims about vaccines and vaccine-preventable diseases, which undermines public confidence in the safety and effectiveness of vaccines. Dr. Offit referred to Kennedy as “an anti-vaccine activist” and noted that his long-standing belief is that vaccines do more harm than good. Although Kennedy has tentatively endorsed the measles, mumps, and rubella (MMR) vaccine, he has also made false claims about its components.
Recently, Kennedy made misleading statements regarding treatments for measles, suggesting that antibiotics like clarithromycin and steroids like budesonide could lead to “miraculous and instantaneous recovery.” However, leading health authorities, including the American Academy of Pediatrics (AAP), emphasize that there is no cure for measles, and the best preventive measure is vaccination with the MMR vaccine, which boasts a 97% effectiveness rate.
Measles is a highly contagious virus that can result in severe complications, including death, with about one in 1,000 infected children succumbing to the disease. Furthermore, measles can lead to serious conditions such as encephalitis, which may cause lifelong disabilities. Experts urge the public to recognize that promoting unproven treatments for measles is not only misleading but also dangerous. The best strategy to combat measles outbreaks is through widespread vaccination, safeguarding both individual and public health.
