Related Experiment Video
Updated: Jul 10, 2025

A Method of Trigonometric Modelling of Seasonal Variation Demonstrated with Multiple Sclerosis Relapse Data
Published on: December 9, 2015
The lingering symptoms of post-COVID-19 condition (long-COVID): a prospective cohort study
Stuart Tan1,2,3, Anna J G Pryor4, Geoffrey W Melville4,5
1Physician in Trauma and Rehabilitation Medicine, Illawarra Shoalhaven Local Health District, New South Wales, Australia.
Background:
Longer-term symptoms (long COVID) may be present in seemingly recovered patients for several months and can be debilitating.
Aim:
To investigate the prevalence and type of symptoms in those with a prior COVID-19 diagnosis.
Methods:
This prospective, longitudinal observational study commenced in July 2020 investigating the longer-term health impacts of COVID-19. Participants were recruited via public health units and media publicity. Surveys were completed upon enrolment, and at 1, 3, 6 and 12 months. Outcome measures included incidence of activity limitations and symptoms against health and vaccination status, age and gender.
Results:
Overall, 339 participants were recruited. At 3 months after COVID-19, 66.8% reported symptoms, and 44.8% were still experiencing symptoms at 12 months. Fatigue was most common at every point (between 53.1% and 33.1%). Pain symptoms increased in relative prevalence over time, whereas respiratory/pulmonary-type symptoms decreased substantially after 3 months. Females and younger people were more likely to experience symptoms in the early stages of long COVID (P < 0.01) and those with more comorbidities in the latter stages (P < 0.001). Vaccination showed a statistically significant protective effect against symptoms (P < 0.01-0.001).
Conclusion:
Long-term COVID-19 symptoms exist among recovered patients up to 12 months after contracting the virus. Fatigue is a primary contributor, while chronic pain became more problematic after 6 months. Vaccination was a factor in preventing long-term symptoms and aiding faster recovery from symptoms. Further work exploring additional contributors to symptom prevalence would assist in developing appropriate follow-up care.
Related Concept Videos
Observational Studies
There are three types of observational studies – Prospective, retrospective, and cross-sectional.
Prospective Study
Prospective studies, also known as longitudinal or cohort studies, are carried out by collecting future data from groups sharing similar characteristics. One...
Longitudinal Research
Chronic Obstructive Pulmonary Disease-IV: Assessement and Diagnostic Studies
Medical History
COPD: 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...
Chronic Obstructive Pulmonary Disease-I: Introduction
Longitudinal Studies

