CDC Releases 2022 Lyme Disease Case Numbers

February 17, 2024

Morbidity and Mortality Weekly Report (Kugeler, K.J., et al.) 02.15.2024, published “Surveillance for Lyme Disease After Implementation of a Revised Case Definition — United States, 2022.” This report describes the impact of the revised surveillance case definition in 2022. A total of 62,551 Lyme cases were reported to the CDC in 2022. This number, compared to an annual average of 37,118 cases reported from 2017-2019, was a 69% increase in case numbers. There was a 73% increase in high-incidence jurisdictions and a 10% increase in low-incidence jurisdictions.

High incidence jurisdictions are no longer required to conduct case investigations to obtain clinical information for reporting. Cases in high-incidence jurisdictions (Connecticut, Delaware, District of Columbia, Maine, Maryland, Massachusetts, Minnesota, New Hampshire, New Jersey, New York, Pennsylvania, Rhode Island, Vermont, Virginia, West Virginia, and Wisconsin) are now based on laboratory evidence alone, reducing the investigational burden for public health resources in these states. As predicted in the paper, “Potential quantitative effect of a laboratory-based approach to Lyme disease surveillance in high-incidence states,” this significant increase is likely the outcome of changes in surveillance methods rather than change in disease risk. New data going forward will be difficult to compare to data collected prior to 2022.

The increase in case numbers is still an underreporting of actual cases of Lyme disease as early Lyme is often diagnosed without lab testing. The CDC estimates that nearly 500,000 people are diagnosed and treated for Lyme disease annually.

For More Information:

Read the Morbidity and Mortality Weekly Report

Read the 2022 Lyme Disease Case Definition