LB15. Measles Outbreak in New York State (NYS) Outside of New York City, 2018–2019

BACKGROUND: The United States is experiencing one of the largest and longest measles outbreaks since elimination was declared in 2000 and is at risk of losing this status. Most cases occurring in NYS were reported in undervaccinated communities. METHODS: We included all confirmed NYS measles cases (excluding NYC) from outbreak counties from October 1, 2018 to July 25, 2019. We used the CSTE measles case definition requiring an acute febrile rash illness and either laboratory confirmation or direct epidemiologic linkage to a lab-confirmed case. For each case, demographic and clinical characteristics were obtained. A medical record review was completed for those reported to have an encounter at a hospital, emergency department, or urgent care center. RESULTS: There were 371 cases of measles reported, including 11 internationally imported cases. Most occurred in Rockland county (n = 283); followed by Orange (n = 55), Westchester (n = 18), Sullivan (n = 14) and Greene (n = 1) (Figures 1 and 2). The median age was 5.5 years; 79% of all cases occurred among children younger than 18 years of age (Figure 3). Most cases (79%) had not received any doses of measles vaccine. Of the 371 cases, 263 (71%) were children who had received 0 doses of measles, mumps, rubella vaccine (MMR), 218 (83%) of whom were over 1 year of age (Table 1). There have been no deaths or documented cases of encephalitis. Twenty-eight (8%) patients were diagnosed with pneumonia and 25 (7%) patients were hospitalized. Among 17 hospitalized children, 5 (29%) were admitted to the intensive care unit (ICU) (ages 1 day to 7 years). There were two preterm births at 34 and 25 weeks gestation to women with measles while pregnant. During October 1, 2018–July 31, 2019, providers in outbreak counties vaccinated 72,465 individuals with MMR, a 46% increase from the same period the year prior. CONCLUSION: Unvaccinated children were identified as the largest group affected and experienced severe complications; nearly 30% of hospitalized children were admitted to an ICU. These data support the critical need for continued education and outreach on the risks of measles and the value of vaccination to prevent continued circulation in undervaccinated communities and potential further cases of severe disease. [Image: see text] [Image: see text] [Image: see text] [Image: see text] DISCLOSURES: Kirsten St. George, MAppSc, PhD, Akonni Biosystems (Other Financial or Material Support), ThermoFisher (Grant/Research Support), Zeptometrix (Other Financial or Material Support, royalty generating collaborative agreement); others, no disclosures reported..