Measles Cases Surge in the U.S.: A Growing Concern
Measles, a highly contagious viral disease, is witnessing a worrying resurgence in the United States. As of May 2025, the U.S. Centers for Disease Control and Prevention (CDC) has reported 935 confirmed cases across 30 states, a significant increase from 285 cases in 2024. Texas has emerged as the epicenter of the outbreak, with 702 cases, 91 hospitalizations, and three fatalities, including two children. Experts are now warning that measles could become endemic in the U.S. for the first time in 25 years if vaccination rates do not improve.
Global Measles Trends Reflect a Larger Issue
The rise in measles cases is not confined to the U.S. Globally, measles is on the rise in Canada, Mexico, South America, and parts of Europe. Canada has reported 1,177 cases as of April 2025, with most linked to an outbreak that began in New Brunswick in late 2024. Mexico has confirmed 421 cases, while Europe is experiencing its highest measles rates in 25 years, with 35,212 cases reported in 2024. These trends highlight a global decline in vaccination rates, exacerbated by the COVID-19 pandemic.
Why Measles Is So Contagious and Dangerous
Measles is one of the most contagious diseases known, with an R0 (basic reproduction number) of 12 to 18, meaning one infected person can spread the virus to 12 to 18 others. This is significantly higher than the R0 for influenza (1 to 4) and COVID-19 (2 to 5). The disease can lead to severe complications, including pneumonia, encephalitis, and death. In Texas alone, 13% of infected individuals have been hospitalized during the current outbreak.
The Role of Vaccination in Preventing Measles
Vaccination has been the cornerstone of measles prevention. The measles, mumps, and rubella (MMR) vaccine is 97% effective after two doses. To achieve herd immunity and prevent outbreaks, at least 95% of the population must be vaccinated. However, vaccination rates have been declining globally, with a sharp drop during the COVID-19 pandemic due to limited access to healthcare and rising vaccine hesitancy.
Could Measles Become Endemic Again?
Measles was declared eliminated in the U.S. in 2000, meaning there was no continuous transmission of the disease within the country. However, experts now warn that measles could re-establish endemicity if vaccination rates remain low. A recent study published in JAMA predicts that the U.S. could experience up to 850,000 measles cases over the next 25 years under current vaccination rates. If vaccination rates decline further, this number could rise to 11 million cases.
What Needs to Be Done?
Reversing the trend will require a concerted effort to increase vaccination rates. According to the JAMA study, boosting vaccination rates by just 5% could reduce the number of measles cases to between 3,000 and 19,000 over the next 25 years. Public health campaigns must focus on restoring trust in vaccines and ensuring access to free and accessible childhood immunizations. Early intervention during outbreaks is also crucial; containing outbreaks is possible if at least 85% of the population is vaccinated.
The resurgence of measles serves as a stark reminder of the importance of vaccination. As the U.S. and other countries grapple with rising cases, the need for robust public health measures and community engagement has never been more urgent. By addressing vaccine hesitancy and improving access to immunizations, it is possible to prevent measles from becoming endemic again and protect future generations from this preventable disease.
Source: The Conversation, Reuters, CDC, JAMA