Post-acute sequelae of COVID-19 3 to 12 months after infection: Delta vs Omicron.

Objectives: Studies have shown temporal changes in post-acute sequelae of COVID-19 (PASC) prevalence for early SARS-CoV-2 variants, although often lacking controls. This prospective study assesses the prevalence of symptoms in Delta- and Omicron-infected cases up to 12 months compared with population controls.

Methods: Adult participants filled out surveys every 3 months (T0-T12) between July 2021 and August 2023. Cases were recruited with a positive SARS-CoV-2 test during the Delta or Omicron domination. Population controls were randomly invited from the Dutch Personal Records Database. Participants indicated the presence of 13 PASC-associated symptoms, and severity scores of fatigue, cognitive impairment, dyspnea, and pain. PASC prevalence was defined as the excess prevalence of havingat least one PASC-associated symptom in cases compared with population controls.

Results: PASC prevalence was 34.3% at T3 and decreased to 21.7% at T12 for Delta and decreased from 18.7% at T3 to 16.7% at T12 for Omicron. At T12, the difference between Delta and Omicron was not significant. Delta cases generally had higher excess symptom scores for fatigue, dyspnea, and cognitive impairment than Omicron.

Conclusions: In the first 9 months after infection, PASC prevalence was higher for Delta than Omicron, but the difference reduced over time and approximated after 12 months.