Prevalence of and Risk Factors for Post-COVID-19 Condition during Omicron BA.5-Dominant Wave, Japan.

The increased risk for post-COVID-19 condition after the Omicron-dominant wave remains unclear. This population-based study included 25,911 persons in Japan 20-69 years of age with confirmed SARS-CoV-2 infection enrolled in the established registry system during July-August 2022 and 25,911 age- and sex-matched noninfected controls who used a self-reported questionnaire in January-February 2023. We compared prevalence and age- and sex-adjusted odds ratios of persistent COVID-19 symptoms (lasting ≥2 months). We evaluated factors associated with post-COVID-19 condition by comparing cases with and without post-COVID-19 condition. We analyzed 14,710 (8,392 cases and 6,318 controls) of 18,183 respondents. Post-COVID-19 condition proportion among cases was 11.8%, higher by 6.3% than 5.5% persistent symptoms among controls. Female sex, underlying medical conditions, mild to moderate acute COVID-19, and vaccination were associated with post-COVID-19 condition. Approximately 12% had post-COVID-19 condition during the Omicron-dominant wave, indicating the need for longer follow-up.