The US Centers for Disease Control and Prevention (CDC) has recorded the country's third measles death this year, as the United States confronts its largest measles outbreak in decades.
The CDC did not specify which state the death occurred in. The federal agency's tally remains lower than the figures published by state officials, particularly in Pennsylvania, the hardest-hit state. As of the end of Monday, Pennsylvania had reported 1,286 cases and five deaths.
The CDC confirmed the new death after the National Center for Health Statistics (NCHS) verified that measles was listed as the underlying cause of death on the death certificate.
According to the CDC, 4,410 measles cases had been recorded nationwide as of October 15. The agency said the death toll could change as further review steps are completed. In Pennsylvania, the outbreak has spread beyond the initial epicenter in Lancaster County, with 42 counties now reporting cases.
How federal authorities count measles deaths is drawing scrutiny after the CDC shifted to relying on NCHS mortality data rather than reports from state health departments.
The CDC previously told Al Jazeera that it was working with the Council of State and Territorial Epidemiologists to develop a standardized definition for measles deaths. In the meantime, it will use NCHS mortality data as its measure.
