Long-term health effects of Omicron infection, particularly persistent Long COVID in hospitalized patients, require further investigation.
Methods
Patients hospitalized for Omicron infection (Dec 2022–Mar 2023) underwent follow-ups at 6 months and 1 year post-discharge. Univariate/multivariate analyses identified mortality predictors, symptom trends, and optimal CRP levels (mg/L) thresholds.
Results
Among 410 patients, 59 died; mortality predictors included age (OR = 1.070), ICU admission (OR = 15.748), diabetes (OR = 3.363), antibacterial use (OR = 0.283), and lymphocyte count (OR = 0.099). At 6 months, 86.0% reported ≥1 symptom (83.5% at 1 year). Fatigue, cough, and snoring were most common, with symptom counts decreasing significantly over time. Symptomatic patients had longer hospital stays (P = 0.022), lymphopenia (P = 0.036), and elevated CRP levels (P = 0.010). A CRP level ≥15.38 mg/L was associated with a greater risk of symptom persistence and may serve as a potential predictive marker.
Conclusion
Hospitalized Omicron survivors experience prolonged symptoms, with ICU admission, age, and diabetes as key mortality risks. Fatigue and snoring may persist despite overall improvement. Elevated CRP and prolonged hospitalization in symptomatic patients underscore the need for long-term monitoring and interventions targeting high-risk groups.
MahaseE. COVID-19: WHO declares pandemic because of “alarming levels” of spread, severity, and inaction. Br Med J2020; 368: m1036.
2.
LinaBBauerJ. SARS-CoV-2 genetic diversity: its impact on vaccine efficacy. Infect Dis Now2022; 52: S2–s3.
3.
FanYLiXZhangL, et al.SARS-CoV-2 omicron variant: recent progress and future perspectives. Signal Transduct Target Ther2022; 7: 141.
4.
CarfìABernabeiRLandiF. Persistent symptoms in patients after acute COVID-19. Jama2020; 324: 603–605.
5.
ShenSZhaoXPeiJ, et al.Exploring the psychological impact of long COVID: symptoms, mechanisms, and treatments. Front Psychiatry2025; 16: 1555370.
6.
ElyEWBrownLMFinebergHV. Long COVID Defined. N Engl J Med2024; 391: 1746–1753.
7.
WangSQuanLChavarroJE, et al.Associations of depression, anxiety, worry, perceived stress, and loneliness prior to infection with risk of post-COVID-19 conditions. JAMA Psychiatry2022; 79: 1081–1091.
8.
HedinKvan der VeldenAWHansenMP, et al.Initial symptoms and three months follow-up after acute COVID-19 in outpatients: an international prospective cohort study. Eur J Gen Pract2023; 29: 2154074.
9.
ZangCHouYSchenckEJ, et al.Identification of risk factors of long COVID and predictive modeling in the RECOVER EHR cohorts. Commun Med (Lond)2024; 4: 130.
10.
AntonelliMPujolJCSpectorTD, et al.Risk of long COVID associated with delta versus omicron variants of SARS-CoV-2. Lancet2022; 399: 2263–2264.
11.
BestallJCPaulEAGarrodR, et al.Usefulness of the medical research council (MRC) dyspnoea scale as a measure of disability in patients with chronic obstructive pulmonary disease. Thorax1999; 54: 581–586.
12.
JonesPWAdamekLNadeauG, et al.Comparisons of health status scores with MRC grades in COPD: implications for the GOLD 2011 classification. Eur Respir J2013; 42: 647–654.
13.
AronsonKIMartin-SchwarzeAMSwigrisJJ, et al.Validity and reliability of the fatigue severity scale in a real-world interstitial lung disease cohort. Am J Respir Crit Care Med2023; 208: 188–195.
14.
ZhouMDaiXYuanF. Improved fatigue management in primary sjögren's syndrome: a retrospective analysis of the efficacy of methotrexate in Chinese patients. J Inflamm Res2024; 17: 7551–7560.
15.
ScharfMT. Reliability and efficacy of the epworth sleepiness scale: is there still a place for it?Nat Sci Sleep2022; 14: 2151–2156.
16.
PengLLLiJRSunJJ, et al.Reliability and validity of the simplified Chinese version of epworth sleepiness scale. Zhonghua Er Bi Yan Hou Tou Jing Wai Ke Za Zhi2011; 46: 44–49.
17.
LimPVCurryAR. A new method for evaluating and reporting the severity of snoring. J Laryngol Otol1999; 113: 336–340.
18.
YuLMaoRZhangC, et al.Clinical study of two mandibular advancement devices in the treatment of obstructive sleep apnea: a pilot randomized controlled trial. BMC Oral Health2024; 24: 1492.
19.
ChenYKleinSLGaribaldiBT, et al.Aging in COVID-19: vulnerability, immunity and intervention. Ageing Res Rev2021; 65: 101205.
20.
AndersonJJSusserEArbeevKG, et al.Telomere-length dependent T-cell clonal expansion: a model linking ageing to COVID-19T-cell lymphopenia and mortality. EBioMedicine2022; 78: 103978.
21.
WangYWangQHeF, et al.Age-dependent decrease of circulating T follicular helper cells correlates with disease severity in elderly patients with COVID-19. Clin Immunol2024; 266: 110329.
22.
Fuenmayor-GonzálezLVera-OrmazaJShenH, et al.Risk factors for COVID-19 and their association with mortality in Ecuadorian patients admitted to the ICU: a retrospective cohort multicentric study. Medicine (Baltimore)2024; 103: e38776.
23.
DemouleAFartoukhMLouisG, et al.ICU Strain and outcome in COVID-19 patients-A multicenter retrospective observational study. PLoS One2022; 17: e0271358.
24.
Virseda-BerdicesABehar-LagaresRMartínez-GonzálezO, et al.Longer ICU stay and invasive mechanical ventilation accelerate telomere shortening in COVID-19 patients 1 year after recovery. Crit Care2024; 28: 267.
25.
XuYSangLWangY, et al.Impact of diabetes on COVID-19 and glucocorticoids on patients with COVID-19 and diabetes during the omicron variant epidemic: a multicenter retrospective cohort study in south China. BMC Infect Dis2024; 24: 706.
26.
TanJKLimGHMohamed SalimNN, et al.Associations between mean HbA1c, HbA1c variability, and both mortality and macrovascular complications in patients with diabetes Mellitus: a registry-based cohort study. Clin Epidemiol2023; 15: 137–149.
27.
ChauguleAHowardKSimonsonDC, et al.Predictors of readmission and mortality in adults with diabetes or stress hyperglycemia after initial hospitalization for COVID-19. BMJ Open Diabetes Res Care2024; 12.
28.
GolliALZlatianOMCaraML, et al.Pre- and Post-COVID-19 Antimicrobial Resistance Pattern of Pathogens in an Intensive Care Unit. Pharmaceuticals (Basel)2024; 17: 407.
29.
HelmiRTAl-MaqbaliJSGamalS, et al.Short-term effects of antimicrobial stewardship programs on antibiotics usage, clinical outcomes, and multidrug resistant organisms in the post COVID-19 era. J Infect Public Health2024; 17: 819–824.
30.
MihalovPHodosyJKoščálováA, et al.Antimicrobial therapy as a risk factor of multidrug-resistant Acinetobacter infection in COVID-19 patients admitted to the intensive care unit. Can J Infect Dis Med Microbiol2023; 2023: 4951273.
31.
DumanDKarakurtZDurmuş KoçakN, et al.Are lymphocytes and eosinophils associated with the COVID-19 severity: a large, retrospective study. Thorac Res Pract2023; 24: 6–13.
32.
XuXHuangJZhangH, et al.Differential expression of lymphocyte subpopulations in the peripheral blood of patients with COVID-19: implications for disease severity and prognosis. Immun Inflamm Dis2024; 12: e1281.
33.
Arango-IbanezJPCórdoba-MeloBDGutiérrez PossoJM, et al.Long COVID Clusters of Symptoms Persist beyond Two Years after Infection: Insights from the CARDIO COVID 20-21 Registry. Viruses2024; 16: 1028.
34.
Gutiérrez-CanalesLGMuñoz-CoronaCBarrera-ChávezI, et al.Persistence of COVID-19 Symptoms and Quality of Life at Three and Twelve Months after Hospital Discharge. Medicina (Kaunas)2024; 60: 944.
35.
ArishNIzbickiGRokachA, et al.Association of the risk of obstructive sleep apnoea with the severity of COVID-19. PLoS One2023; 18: e0284063.
36.
LinWCWuMCWangYH, et al.The prevalence of obstructive sleep apnea syndrome after COVID-19 infection. J Med Virol2024; 96: e29392.
37.
PhetsouphanhCDarleyDRWilsonDB, et al.Immunological dysfunction persists for 8 months following initial mild-to-moderate SARS-CoV-2 infection. Nat Immunol2022; 23: 210–216.
38.
ZhangHHuangCGuX, et al.3-year Outcomes of discharged survivors of COVID-19 following the SARS-CoV-2 omicron (B.1.1.529) wave in 2022 in China: a longitudinal cohort study. Lancet Respir Med2024; 12: 55–66.
39.
NugentKBerdineG. Dyspnea and long COVID patients. Am J Med Sci2024; 368: 399–404.
40.
Iam-ArunthaiKChamnanchanuntSThungthongP, et al.COVID-19 with high-sensitivity CRP associated with worse dynamic clinical parameters and outcomes. Front Med (Lausanne)2024; 11: 1346646.
41.
CheKZengZHongC, et al.Association between serum C-reactive protein (CRP) and omicron variant COVID-19 pneumonia in cancer patients: a multicenter cross-sectional study at the end of 2022 in China. Medicine (Baltimore)2024; 103: e36965.
42.
AvihaiBSundelEPLeeE, et al.CRP Monitoring in Early Hospitalization: Implications for Predicting Outcomes in Patients with COVID-19. Pathogens2023; 12: 1315.
43.
SykesDLVan der Feltz-CornelisCMHoldsworthL, et al.Examining the relationship between inflammatory biomarkers during COVID-19 hospitalization and subsequent long-COVID symptoms: a longitudinal and retrospective study. Immun Inflamm Dis2023; 11: e1052.
44.
WynbergEHanAXvan WilligenHDG, et al.Inflammatory profiles are associated with long COVID up to 6 months after COVID-19 onset: a prospective cohort study of individuals with mild to critical COVID-19. PLoS One2024; 19: e0304990.
45.
RadkhahHOmidaliMHejratiA, et al.Correlations of long COVID symptoms and inflammatory markers of complete blood count (CBC): a cross-sectional study. J Community Hosp Intern Med Perspect2023; 13: 112–119.
Supplementary Material
Please find the following supplemental material available below.
For Open Access articles published under a Creative Commons License, all supplemental material carries the same license as the article it is associated with.
For non-Open Access articles published, all supplemental material carries a non-exclusive license, and permission requests for re-use of supplemental material or any part of supplemental material shall be sent directly to the copyright owner as specified in the copyright notice associated with the article.
