Epidemiology of post-COVID conditions beyond 1 year: a cross-sectional study.

OBJECTIVE: The aim of this study was to investigate the epidemiology of post-COVID conditions beyond 12 months and identify factors associated with the persistence of each condition. STUDY DESIGN: This was a cross-sectional questionnaire-based survey. METHODS: We conducted the survey among patients who had recovered from COVID-19 and visited our institute between February 2020 and November 2021. Demographic and clinical data and data regarding the presence and duration of post-COVID conditions were obtained. We identified factors associated with the persistence of post-COVID conditions using multivariable linear regression analyses. RESULTS: Of 1148 surveyed patients, 502 completed the survey (response rate, 43.7%). Of these, 393 patients (86.4%) had mild disease in the acute phase. The proportion of participants with at least one symptom at 6, 12, 18, and 24 months after symptom onset or COVID-19 diagnosis was 32.3% (124/384), 30.5% (71/233), 25.8% (24/93), and 33.3% (2/6), respectively. The observed associations were as follows: fatigue persistence with moderate or severe COVID-19 (ß = 0.53, 95% confidence interval [CI] = 0.06-0.99); shortness of breath with moderate or severe COVID-19 (ß = 1.39, 95% CI = 0.91-1.87); cough with moderate or severe COVID-19 (ß = 0.84, 95% CI = 0.40-1.29); dysosmia with being female (ß = -0.57, 95% CI = -0.97 to -0.18) and absence of underlying medical conditions (ß = -0.43, 95% CI = -0.82 to -0.05); hair loss with being female (ß = -0.61, 95% CI = -1.00 to -0.22), absence of underlying medical conditions (ß = -0.42, 95% CI = -0.80 to 0.04), and moderate or severe COVID-19 (ß = 0.97, 95% CI = 0.41-1.54); depressed mood with younger age (ß = -0.02, 95% CI = -0.04 to -0.004); and loss of concentration with being female (ß = -0.51, 95% CI = -0.94 to -0.09). CONCLUSIONS: More than one-fourth of patients after recovery from COVID-19, most of whom had had mild disease in the acute phase, had at least one symptom at 6, 12, 18, and 24 months after onset of COVID-19, indicating that not a few patients with COVID-19 suffer from long-term residual symptoms, even in mild cases.

Post COVID-19 condition of the Omicron variant of SARS-CoV-2.

OBJECTIVES: To investigate the prevalence of post coronavirus disease (COVID-19) condition of the Omicron variant in comparison to other strains. STUDY DESIGN: A single-center cross-sectional study. METHODS: Patients who recovered from Omicron COVID-19 infection (Omicron group) were interviewed via telephone, and patients infected with other strains (control group) were surveyed via a self-reporting questionnaire. Data on patients' characteristics, information regarding the acute-phase COVID-19, as well as presence and duration of COVID-19-related symptoms were obtained. Post COVID-19 condition in this study was defined as a symptom that lasted for at least 2 months, within 3 months of COVID-19 onset. We investigated and compared the prevalence of post COVID-19 condition in both groups after performing propensity score matching. RESULTS: We conducted interviews for 53 out of 128 patients with Omicron and obtained 502 responses in the control group. After matching cases with controls, 18 patients from both groups had improved covariate balance of the factors: older adult, female sex, obesity, and vaccination status. There were no significant differences in the prevalence of each post COVID-19 condition between the two groups. The number of patients with at least one post COVID-19 condition in the Omicron and control groups were 1 (5.6%) and 10 (55.6%) (p = 0.003), respectively. CONCLUSIONS: The prevalence of post Omicron COVID-19 conditions was less than that of the other strains. Further research with a larger sample size is needed to investigate the precise epidemiology of post COVID-19 condition of Omicron, and its impact on health-related quality of life and social productivity.