1631. Background Incidence Rates of Health Outcomes Relevant to Vaccine Monitoring in Lyme Disease Endemic and Non-endemic US Regions using Administrative Claims Data

BACKGROUND: A 6-valent vaccine (VLA15) is being tested in clinical trials for the prevention of Lyme disease caused by Borrelia burgdorferi sensu lato strains expressing OspA serotypes 1-6. Background incidence rates (IRs) of health outcomes in Lyme disease endemic and non-endemic regions of the US may help to contextualize whether the frequencies of events reported during vaccine clinical trials or post-marketing are consistent with expected population level rates. The objective of this study was to estimate and compare IRs of health outcomes in Lyme disease endemic vs. non-endemic regions using US administrative claims data. METHODS: IQVIA PharMetrics(®) Plus commercial claims database was used to estimate IRs of 63 outcomes relevant to vaccine safety monitoring in the US during 01/01/2017-12/31/2019. Endemic regions were classified using 3-digit zip codes that overlapped with Lyme disease high incidence counties (10 cases/100,000 persons) according to the CDC. Analyses included all individuals aged ≥ 2 years with ≥ 1 year of enrollment. Outcomes were defined by ICD-10-CM diagnosis codes according to the literature or expert input and required ≥ 1 inpatient or ≥ 2 outpatient claims/codes. Crude IRs and 95% confidence intervals (CIs) were calculated for each outcome and compared between endemic vs. non-endemic regions using IR ratios (IRR). RESULTS: The study population included 8.7M in endemic and 27.8M in non-endemic regions. Mean age was slightly higher in endemic (37.7 yrs [SD=18.9]) vs. non-endemic (36.8 yrs [SD=19.5]) cohorts, and 51% in both cohorts were female. Table 1 provides a summary of the IRs and IRRs for the 10 highest and 10 lowest ranking IRRs for health conditions by endemic region status. IRRs (95% CI) ranged from a low of 0.74 (0.71, 0.78) for systemic lupus erythematosus to a high of 2.14 (1.93, 2.37) for meningoencephalitis. [Figure: see text] CONCLUSION: This study identified potential differences between Lyme endemic and non-endemic regions of the US in background IRs of health conditions in vaccine safety monitoring. Differences in background IRs between endemic and non-endemic regions should be considered when contextualizing possible safety signals in clinical trials and post-marketing. DISCLOSURES: Jill Dreyfus, PhD, MPH, Pfizer, Inc.: Employment|Pfizer, Inc.: Stocks/Bonds Swapna Munnangi, PhD, IQVIA: Employment Camilla Bengtsson, PhD, IQVIA: Employment|Pfizer, Inc: Advisor/Consultant Barbara Correia, PhD, IQVIA: Employee|Pfizer, Inc.: Advisor/Consultant Rejane Figueiredo, PhD, IQVIA: Biostatistician Sarah Galvin, BS, Pfizer, Inc.: Employment James H. Stark, PhD, Pfizer: Employee|Pfizer: Stocks/Bonds Michele Zawora, MD, FAAFP, Pfizer: Employment|Pfizer: Stocks/Bonds Mark Riddle, MD, DrPH, Pfizer: Employee salary Jason Maguire, MD, Pfizer, Inc.: Employee|Pfizer, Inc.: Stocks/Bonds Qin Jiang, PhD, Pfizer: Employee|Pfizer: Employee|Pfizer: Stocks/Bonds|Pfizer: Stocks/Bonds Juan Naredo Turrado, MS, IQVIA: Employee Steven Bailey, MD, MPH, MBA, Pfizer, Inc.: Employment