Urbanicity and Lyme Disease: 20 Year Trends in Incidence and Case Burden in the United States

Incidence of Lyme disease (LD) has increased over the last few decades in the United States (US). We examined trends in LD incidence and case burden in high‐incidence jurisdictions in the US from 2000 to 2021 by urbanicity. County‐level counts of confirmed LD cases from 2000 to 2021 were obtained from national surveillance data. Incidence rates were calculated using census population projections. Urbanicity was categorized using Rural–Urban Continuum Codes (RUCC). Mixed effects models were used to analyze annual changes in LD incidence. Over 70% of LD cases each year were residents of metro counties. All RUCCs had an incidence greater than 10 LD cases per 100,000 per year from 2001 to 2021. LD incidence significantly increased across all RUCCs, with the largest estimated increases in counties in moderately urban areas. Urban populations have substantially contributed to the overall burden of LD in the US, whereas populations in more moderately urban areas had the largest estimated increases in LD incidence. These findings highlight the need for targeted educational interventions and public health measures across urbanicity levels to address the rising burden of LD in the US.