Incidence of long COVID among U.S. children and adults during the omicron era - Tracking Post-COVID Conditions (Track-PCC) network, 2022-2023.

Background: Long COVID, or Post-COVID Conditions (PCC), refers to new and persisting sequelae occurring in the months following an acute SARS-CoV-2 infection. Although previous studies have reported estimates of PCC incidence, few have examined trends during the Omicron variant period or have included geographically distinct regions for the same time periods.

Methods: Track PCC is a surveillance network, leveraging electronic health records and public health data to monitor incidence over time across five diverse geographic sites in the U.S. This study examines the incidence of PCC in children and adults during the Omicron predominance period (January 1, 2022, to December 31, 2023) through April 2024. Incident conditions were identified using diagnostic codes for 49 conditions. Crude and adjusted incidence for the occurrence of PCC per 1000 person-days was calculated independently during three post-acute time periods: 31-90 days, 91-180 days, and 181-365 days. Incidence of PCC per 1000 person-days was also calculated by demographic and clinical characteristics.

Results: The Track PCC network included 438,491 adults and 85,264 children with COVID-19 during the Omicron period. PCC incidence was highest 31-90 days post-acute; range from 2.95 to 5.05 per 1000 person-days among adults and 1.53-3.15 per 1000 person-days among children. Incidence was higher among older patients and patients with 3 or more co-morbidities and generally stable across variant sublineage periods.

Conclusion: These data suggest the PCC incidence following acute COVID-19 has not increased during the Omicron period. This is useful for understanding the burden of PCC and estimating demand of medical services following acute COVID-19 infections. PCC surveillance, including tracking the incidence of PCC, understanding patients at higher likelihood of developing PCC, and creating robust estimates, is critical to public health efforts to understand disease burden and guide prevention and treatment efforts.