Why are measles cases rising so fast?
A rapid resurgence of a preventable disease
Measles has surged across multiple countries in 2026, driven largely by gaps in vaccination. National and local health reports show the United States has logged nearly 1,000 cases so far this year, a multiple-fold increase over the same period last year. Large localized outbreaks have emerged in several places: a major cluster centered in Spartanburg, South Carolina, and a fast-spreading outbreak among under-10s in north‑east London that has infected more than 60 children and led to hospital admissions.
What’s driving the rise
- Under-vaccination: Many of the affected children were not protected by the measles, mumps and rubella (MMR) vaccine. Declining uptake in some communities has left pockets of susceptibility.
- Local transmission: When measles reaches under-immunized groups, it spreads extremely efficiently because it is one of the most contagious viruses known.
- Surveillance and reporting gaps: Some states do not require hospitals to report measles-related admissions, which can obscure the full clinical burden and delay targeted responses.
Public health response
- Vaccination campaigns and curbside clinics have been mounted in outbreak areas.
- Health officials have urged parents to check immunization records and get children vaccinated; some local authorities have considered or used school exclusion policies for close contacts.
- Internationally, affected regions have used a mix of mask recommendations and intensified school screening; one Mexican state mandated masks in schools amid rising cases.
Why it matters
Measles causes severe complications including pneumonia, encephalitis and hospitalization, and can be fatal—risks that are highest in unvaccinated children. The outbreaks underscore how vaccine coverage gaps can quickly reverse decades of progress. It remains uncertain how widely the current surges will spread and how long intensified public health measures will be needed.