Measles have been eliminated in the United States of America since the year 2000. However, measles cases have reached its highest in 35 years with 2,318 cases logged by the Centers for Disease Control and Prevention as of the start of 2026.
Measles is a highly contagious disease which causes high fever, coughing, runny nose, red and watery eyes, and a rash; in extreme cases, symptoms include ear infections, diarrhea, pneumonia, encephalitis, and possible death. Starting in 1912, it was required for doctors and laboratories in the U.S. to report all cases to the CDC, where within the first decade, there was an average of 6,000 measles-related deaths annually. To combat this, John F. Enders and Dr. Thomas C. Peebles sought to find a vaccine; they collected the blood of several ill students and used this to create a vaccine for the strain of measles isolated — the Edmonston-B strain. The vaccine was released in 1963, and an updated version was released in 1968 for the Edmonston-Enders strain, which has been the only measles vaccine used in the U.S. since its release.
In 1989, the measles broke out among a group of vaccinated children, leading to the Advisory Committee on Immunization Practices, the American Academy of Pediatrics, and the American Academy of Family Physicians to recommend a second dose of the MMR (a combination of the measles, mumps, and rubella vaccines) for children. This greatly reduced the amount of reported cases of measles throughout the U.S.
For the MMR vaccine to provide herd immunity (the entire population is protected from a disease with only a portion being vaccinated), 95% of the population must be vaccinated. However, this number has now dropped to 92.5%, leaving people who are unvaccinated at a heightened risk of catching the measles.
In 2025, there were a total of 2,286 cases across the U.S compared to 282 cases as of 2024 which is an increase of over 710%. Within the first half of 2026, there have been 2,175. Assuming this will increase at a constant rate, there will be a total of 4,350 cases over the year, resulting in a 90% increase from 2025 to 2026. This is directly related to the declining vaccination rate across the United States, with a 78% decline between 2019 through 2024. If the vaccination rate continues to decline, it is believed that the measles could return to endemic levels.
A major reason for this decline in vaccination rates is that President Donald J. Trump stated that the MMR vaccine should be separated into 3 independent vaccinations against measles, mumps, and rubella. This follows a similar pattern against the DTP (Diphtheria, Tetanus and Pertussis) vaccination. There is a myth claiming that rubella vaccine contains fetal tissue: This stemmed from fetal cells being used in 1960 to replicate the virus, though it has been replicated since then without the use of fetal tissue. There is trace DNA in the vaccine, although it is below the natural background levels found in food across the U.S.
Japan in the 1990s separated the MMR vaccine, leading to a decreased amount of people who received all vaccinations other than the measles vaccine. Because of this, Japan faced outbreaks of rubella in 2013 and 2018. If the U.S. separates the vaccines, it is expected a similar pattern would return. Another reason for the declining vaccination rate is people in disagreement with authorities. Parents, for example, may feel they shouldn’t be requested to give their children vaccines for the health of others, regardless of the benefits. It is due to these factors the vaccination rate drops below the required 95%. To ensure the safety of future generations, it is important to ensure most of the population is vaccinated against measles, mumps, and rubella.
