JONATHAN M. METSCH, DrPH – Tracking Emerging Public Health Challenges – March 25, 2026 – Measles
“Measles was once eliminated in the U.S., but new nationwide analysis of vaccination data from more than 50,000 schools shows that the country is quietly slipping back toward conditions that can sustain large outbreaks. My colleagues and I assembled the most detailed school-by-school measles-mumps-rubella (MMR) vaccination database to date and used a new transmission model to estimate how easily measles could spread in different communities.
“We found that, after the Covid-19 pandemic, the share of children vulnerable to measles roughly doubled from about 5% to 10% and that in 2022–2023 many schools reached levels where a single measles case can trigger ongoing transmission, even though their counties still appear ‘safe’ on paper.” (1)
“According to the Utah Department of Health and Human Services (DHHS), the state now has 486 cases. ABC4 has compiled a list of all confirmed exposure locations over the last three weeks.”
As of Tuesday, Utah has seen 486 confirmed measles cases during the current outbreak, which started in June 2025. The Southwest Utah Health District has the most cases at 233, followed by Utah County at 78, and Salt Lake County at 53.” (2)
Florida measles count at 114, including 83 in Collier. One adult case at Naples school, https://www.wusf.org/health-news-florida/2026-02-27/florida-measles-count-at-114-including-83-in-collier-one-adult-case-at-naples-school
A measles outbreak in Florida is simmering, but we know almost nothing about it. We went to investigate, https://www.cnn.com/2026/03/23/health/florida-measles-outbreak-ave-maria
‘The total number of measles cases remain at 997, with no new cases reported in the state in a week, said Dr. Linda Bell, South Carolina’s epidemiologist.
The outbreak, which began in October and is the largest in the country in decades, has been slowing, helped by strong vaccination efforts.
“The possibility that we could end this outbreak and have measles introduced again from an external source is still a risk and why we will remain vigilant for surveillance for all cases,” Dr. Bell said.” (3)
1.analysis shows how US is slipping toward measles outbreak conditions,by Ana Bento, https://news.cornell.edu/media-relations/tip-sheets/new-analysis-shows-how-us-slipping-toward-measles-outbreak-conditions
2.Utah nears 500 measles cases, with dozens of confirmed exposure locations, by: Amelia Hobson, https://www.abc4.com/news/health/utah-nears-500-measles-cases/
3.South Carolina could declare measles outbreak over by April 26, health official says, By Siddhi Mahatole and Mariam E Sunny, https://www.reuters.com/business/healthcare-pharmaceuticals/south-carolina-measles-outbreak-could-end-by-april-26-health-official-says-2026-03-25/
curated by Jonathan M. Metsch, Dr.P.H.
Clinical Professor of Environmental Medicine, Icahn School of Medicine at Mount Sinai