Surveillance for Lyme Disease After Implementation of a Revised Case Definition - United States, 2022

Abstract

Lyme disease, a tickborne zoonosis caused by certain species of Borrelia spirochetes, is the most common vectorborne disease in the United States. Approximately 90% of all cases are reported from 15 high-incidence jurisdictions in the Northeast, mid-Atlantic, and upper-Midwest regions. After the implementation of a revised surveillance case definition in 2022, high-incidence jurisdictions report cases based on laboratory evidence alone, without need for additional clinical information. In 2022, 62,551 Lyme disease cases were reported to CDC, 1.7 times the annual average of 37,118 cases reported during 2017-2019. Annual incidence increased most in older age groups, with incidence among adults aged ≥65 years approximately double that during 2017-2019. The sharp increase in reported Lyme disease cases in 2022 likely reflects changes in surveillance methods rather than change in disease risk. Although these changes improve standardization of surveillance across jurisdictions, they preclude detailed comparison with historical data.

FIGURE 1

Reported Lyme disease incidence (A) and the ratio of the 2022 incidence to the average 2017–2019 incidence (B), by sex and 5-year age group — United States, 2017–2019 and 2022

FIGURE 2

Week of illness onset or laboratory test and reporting date for reported Lyme disease cases — United States, 2017–2019 and 2022 * Week 1 begins on the first Sunday of the calendar year.