South Carolina's measles outbreak jumped to Washington state 5 times in 2 weeks
International travel used to be the main risk of measles cases in the US—not anymore.
Measles, declared eliminated in the United States in 2000, primarily enters the country through international travelers or unvaccinated residents returning from abroad. However, as vaccination rates decline and outbreaks intensify, domestic travel has become a greater concern. A recent study in NEJM Evidence reveals how an outbreak in South Carolina spread to Washington state through five separate importation events over a two-week period in January.
These instances resulted in 26 cases among Washington state residents before the outbreak was contained. The South Carolina measles outbreak began on October 2, 2025, and concluded on April 26, 2026, with 997 confirmed cases, marking the largest measles outbreak since the virus was declared eliminated in the US. Nonetheless, Pennsylvania's ongoing outbreak has since outpaced it.
Written by urgent.news from Ars Technica Health's reporting — not their text. Machine-written — may contain errors; check the original before relying on it.
