2299. A London Hospital’s Experience of Confirmed Measles Infections and Re-Infections Between 2009 and 2019

Abstract Background 2018 to 2019 has seen a global resurgence in measles cases, with the UK seeing an over 3-fold increase in cases in 2018 compared with 2017. In this context, our center saw a cluster of geographically linked measles cases presenting in the first quarter of 2019. We present this with comparative data of confirmed measles cases from our center over the preceding 10 years. Given the growing recognition of measles “re-infection” in fully vaccinated individuals, we also present our first confirmed cases of reinfection within this cohort. Methods Retrospective analysis of confirmed measles cases (positive Measles IgM or detectable Measles RNA) between 2009 and 2019. Laboratory and demographic data were obtained from electronic patient records. Results 18 cases (of which 14 were adults) of measles (all genotype D8 of those tested) were confirmed in the first 4 months of 2019. 12 presented within a 14 day period from a geographically linked part of North London. There were 4 confirmed measles re-infections (detectable measles RNA on a buccal swab with either a high Measles IgG avidity or previous documented measles immunity). From the 10 year data, cases peaked in 2011 and 2016 consistent with national trends. Of the 89 cases identified, 60 (67%) were adults, who were over twice as likely to be admitted as children, had a longer median length of stay in hospital (2 days vs. 1.5 days) and were more likely to develop a hepatitis (1/10 pediatric cases vs. 26/48 adults, p ≤ 0.01)or other complications. The majority of adults (68%) were unsure of their vaccination status. Conclusion 4 cases of 18 in the first 4 months of 2019 were confirmed re-infections. Re-infections in fully vaccinated individuals are described in the literature, typically presenting with a milder course; however, these are the first cases we have identified at our center. Overall, adult cases were more likely to be admitted to hospital and to have a complicated course compared with children. Vaccination history in adults was of limited clinical utility due to lack of reliable documentation and the potential for reinfection. Disclosures All authors: No reported disclosures.