Related Experiment Video
Updated: Jun 4, 2025
Author Spotlight: Advancements in Multiplex Detection of Respiratory Viruses
Published on: November 10, 2023
Long COVID among the first three waves of COVID-19 in Japan: a multicentre cohort study
Hatsuyo Takaoka1, Ichiro Kawada2,3, Gaku Hiruma4
1Division of Pulmonary Medicine, Department of Medicine, Keio University School of Medicine, Tokyo, Japan.
Objectives:
Severe acute respiratory syndrome coronavirus 2 significantly impacts Japan with a high number of infections and deaths reported. Long coronavirus disease (COVID) characterised by persistent symptoms after COVID-19 has gained recognition but varies across studies. This study aimed to investigate the differences in long COVID among patients hospitalised during Japan's first three waves of the pandemic.
Design:
Multicentre prospective cohort study.
Setting:
26 medical facilities across Japan between February 2020 and February 2021.
Participants:
In total, 1066 hospitalised patients diagnosed with COVID-19 were included with 206, 301 and 559 patients in the first, second and third waves, respectively. Data were collected using electronic data capture and patient-reported outcome forms.
Primary And Secondary Outcome Measures:
Long COVID was assessed at 3, 6 and 12 months after COVID-19 diagnosis.
Results:
Significant differences were observed between the waves in various baseline and clinical characteristics such as age, body mass index (BMI), comorbidities, the severity of COVID-19, complications and treatment during hospitalisation. Long COVID, particularly dyspnoea, was most prevalent in the first wave. Multivariate logistic regression analysis confirmed a significant positive association between the first wave and long COVID including dyspnoea after adjusting for age, sex, BMI, smoking status and COVID-19 severity.
Conclusions:
Patients hospitalised during the first wave had a higher risk of experiencing long COVID, especially dyspnoea, than those hospitalised during the other waves. These findings underscore the need for continued monitoring and managing long COVID in COVID-19 survivors, particularly in those hospitalised during the first wave.
Trial Registration Number:
UMIN000042299.
Related Concept Videos
00:36Viral Mutations
01:18Factors Affecting Illness
For instance, risk factors are connected to illness,...
01:20COPD: Pathogenesis and Clinical Features
The primary cause for the onset of COPD is cigarette smoking and exposure to air pollution. These hazardous factors initiate a chain reaction within the lungs, resulting in chronic inflammation, damage to the airways, and a...
01:22Chronic Obstructive Pulmonary Disease
Smoking is a primary risk factor for COPD, with over 80% of patients having a history of it. Patients typically experience progressive dyspnea or labored breathing, frequent coughing, and recurrent pulmonary infections. Many eventually succumb to respiratory failure, characterized by...
01:25Chronic Obstructive Pulmonary Disease-III: Symptoms and Complications.
Symptoms of COPD can be classified as primary or systemic. Primary symptoms relate to reduced airflow, while systemic or extrapulmonary symptoms relate to COPD's broader impact on the body.
Primary Symptoms of COPD:
01:27Chronic Obstructive Pulmonary Disease-IV: Assessement and Diagnostic Studies
Medical History