The United States is experiencing its worst measles outbreak since 1991, with four unvaccinated deaths reported in Pennsylvania.

What it means

The United States is experiencing its largest measles outbreak since 1991, driven by declining vaccination rates. Pennsylvania has reported four deaths linked to the outbreak, all in unvaccinated individuals, with the latest fatality confirmed in mid-September 2026. The outbreak has spread across dozens of counties, with hundreds of cases and numerous hospitalizations.

Accuracy & sourcesSourced

The claim is solid, based on reporting from STAT News, which cites Pennsylvania health officials and national surveillance data. Multiple outlets (CIDRAP, The Independent, etc.) corroborate the numbers and the broader context of the worst measles year in decades. As a reputable secondary source reporting on a primary public-health data stream, this is well-supported.

How new

Genuinely new: the fourth death was reported on September 15, 2026, and the outbreak is ongoing; this is current coverage of a developing event.

Past coverage

We covered the earlier stage of this outbreak in August 2026, when two deaths in Pennsylvania were reported as the first US measles fatalities of the year (USA Today, Aug 28 2026).

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