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Measles Cases in US More Than Double Previous Year's Total

· Confirmed

Health Desk

In Short: The number of measles cases in the United States has more than doubled compared to last year, with Pennsylvania facing its worst outbreak in three decades.

The total synthesis carried out by Brunner in the year 1995
Photo: Ilimaquinone-Stan / Wikimedia Commons (CC0)

The number of measles cases in the United States has more than doubled compared to last year, reaching 4,588 confirmed cases as of October 2026, according to the Centers for Disease Control and Prevention (CDC).

Since the beginning of 2025, there have been 6,877 confirmed measles cases in the United States, a number that will likely lead to the nation losing its measles elimination status later this year, according to the CDC.

An additional 178 measles cases were reported this week, and over the past two weeks, 508 new measles infections have been confirmed, further exacerbating the ongoing outbreak.

Pennsylvania is at the epicenter of the outbreak, with more than 1,300 cases reported across 44 counties as of October 2026, according to the state health department.

The outbreak has resulted in five measles-associated deaths being identified, plus a sixth death reported recently by a local coroner.

The Pennsylvania Department of Health (DOH) said state health center staff have administered more than 6,500 measles, mumps, and rubella (MMR) vaccinations at pop-up clinics in the affected communities since the outbreak began in late April.

Ten percent of cases overall have required hospitalization, including 16% of the cases in children under 5.

Of the confirmed cases, 17% have been in children under the age of 5, and 42% have been in kids and adolescents ages 5 to 19.

Most of the confirmed cases (96%) have been in people who are unvaccinated or have unknown vaccination status.

The outbreak is the largest of multiple outbreaks across the US, happening amid an uproar over Health Secretary Robert F Kennedy Jr's controversial vaccine stance.

In Pennsylvania, the outbreak has been particularly severe in Lancaster County, which is known for its traditional Amish roots and open farmland.

The outbreak has also spread to other states, with Kentucky reporting 94 confirmed cases and Wisconsin reporting more than 40 new cases over the last 10 days.

What this adds

The outbreak in Pennsylvania has been particularly severe, with Lancaster County reporting 12 new cases since Monday.

The outbreak has also led to a health alert warning of an increase in measles cases among pregnant individuals and the subsequent rise in congenital measles cases, which have not been seen in decades.

The outbreak has also led to a health alert warning of an increase in measles cases among pregnant individuals and the subsequent rise in congenital measles cases, which have not been seen in decades.

Background

Pennsylvania is facing its worst measles outbreak in three decades, with the state health department reporting 1,260 cases as of Friday.

According to the CDC, the number of confirmed US measles cases has hit 4,588, more than doubling its total from last year.

Total internal reflection of Chelonia mydas
Photo: Brocken Inaglory / Wikimedia Commons (CC BY-SA 4.0)

What's confirmed

What's still developing

Sources