Will there be at least 4300 measles cases in the U.S. by October 31, 2026?

Analysis

As of October 8, 2026, the CDC reported 4,080 confirmed measles cases in the United States for the year. That is below the 4,300 threshold, so the forecast leans toward the count not reaching that level by the end of October, though not with certainty. The CDC says its page reflects confirmed cases reported as of 12:00PM on Thursday, and that 2025 to 2026 counts are preliminary and subject to change. Cases are assigned to a year by the epidemiological week of rash onset, so later reports can still be added or revised. The agency also notes that jurisdictions are reporting probable cases, but the page includes only confirmed cases that jurisdictions have notified to CDC. Those probable cases could add to the total if they are confirmed and reported in time, which is the main way the threshold could still be crossed. Most of the count is tied to outbreaks. The CDC reports 42 new outbreaks in 2026, and 96% of confirmed cases, 3,897 of 4,080, are outbreak-associated. Of those, 2,513 come from outbreaks starting in 2026 and 1,384 from outbreaks that started in 2025. Separately, a CDC record dated August 27 describes a South Carolina outbreak of 997 cases between October 2025 and March 2026. The supplied material does not say how much of the 2026 total that outbreak accounts for. The thing to watch is the CDC's weekly Thursday updates. A jump in confirmed cases from new or growing outbreaks would most change the picture.