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Volume 27, Number 10—October 2021
Research Letter

Effects of COVID-19 Pandemic on Reported Lyme Disease, United States, 2020

David W. McCormickComments to Author , Kiersten J. Kugeler, Grace E. Marx, Praveena Jayanthi, Stephanie Dietz, Paul Mead, and Alison F. Hinckley
Author affiliations: Centers for Disease Control and Prevention, Fort Collins, Colorado, USA. (D.W. McCormick, K.J. Kugeler, G.E. Marx, P. Mead, A.F. Hinckley); ICF International Inc., Atlanta, Georgia, USA (P. Jayanthi); Centers for Disease Control and Prevention, Atlanta (P. Jayanthi, S. Dietz)

Main Article


Number and percent positive for Lyme disease tests performed by a large commercial laboratory and percent decrease in 2020 compared with 2019, United States*

Testing tier 2019
% Decrease in testing volume (95% CI) Absolute difference in % positive (95% CI)
Total tests % Positive Total tests % Positive
First tier† 925,939 9.6 691,453 9.2 25.3 (25.2–25.4) 0.3 (0.2–0.4)
Second tier‡

24.2 (24.1–24.3)
0.8 (0.6–0.9)
Total 1,348,740 10.0 1,012,069 9.5 25.0 (25.1–24.9) 0.5 (0.4–0.6)

*Percent positive indicates the percentage of the total laboratory tests that were positive for each test tier and overall. The percent decrease in testing volume shows the percentage decrease in total tests performed by tier and overall for 2020 compared with 2019. Two-tier testing for Lyme disease is recommended, whereby specimens positive or equivocal on the first tier are subjected to the second tier. Additional details about testing tiers are available at

†First-tier tests include enzyme immunoassays for IgM/IgG combined, IgM alone, and C6 antigen.

‡Second-tier tests include immunoblot for IgM or IgG.

Main Article

Page created: July 30, 2021
Page updated: September 19, 2021
Page reviewed: September 19, 2021
The conclusions, findings, and opinions expressed by authors contributing to this journal do not necessarily reflect the official position of the U.S. Department of Health and Human Services, the Public Health Service, the Centers for Disease Control and Prevention, or the authors' affiliated institutions. Use of trade names is for identification only and does not imply endorsement by any of the groups named above.