Lyme disease cases up 70 percent due to reporting change: CDC

Cases of Lyme disease were up about 70 percent nationwide in 2022 compared to years prior, according to data from the Centers for Disease Control and Prevention (CDC), but the agency said there is no cause for alarm because it changed how cases were reported.

About 62,500 cases of Lyme disease were reported in 2022, compared to an average of 31,100 cases between 2017 and 2019, according to CDC data published Thursday. Data from 2020 and 2021 were excluded due to the impact of the COVID-19 pandemic.

The big jump, the CDC said, is because cases that would not have been counted previously are now included in the count.

“Before 2022, many of these cases would have been excluded, either because health departments were unable to obtain the necessary clinical information or because available clinical data were inconsistent with the objective criteria specified in the case definition,” the agency said in a release Thursday.

Lyme disease is the most common tick-borne illness in the U.S., but it is highly localized to the Northeast and Upper Midwest.

The previous reporting requirement excluded many early-stage disease cases that are generally harder to detect. New testing technology also makes identifying Lyme disease easier, the agency said.

Despite the increase, researchers said cases of the disease are still likely under-reported, especially among mild cases and outside of the regions where the disease is most common.