ArticleBMC infectious diseases2024
Long COVID is not the same for everyone: a hierarchical cluster analysis of Long COVID symptoms 9 and 12 months after SARS-CoV-2 test.
Article in BMC infectious diseases, 2024. The graph could read no effect estimate from its abstract, so it casts no vote on the map. An erratum has been issued. Cited by 12 papers.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
12 citing papers in PubMed.
- Longitudinal observation of persistent Long COVID symptoms and health-related quality of life in an adult German cohort.BMC infectious diseases · 2026Observational
- Symptom-based clusters in people with post-COVID-19 condition (PCC).Journal of translational medicine · 2026Article
- Patient and public involvement and engagement in Long COVID research: embedding inclusion in research.Research involvement and engagement · 2026Article
- Long COVID longitudinal symptoms burden clusters within a national community-based cohort.BMC infectious diseases · 2026Article
- Identifying subtypes of Long COVID: a systematic review.EClinicalMedicine · 2026Article
- Factors associated with severe neurological sequelae of COVID-19: findings from the multicenter COVID-BRAIN imaging cohort.Frontiers in human neuroscience · 2026Article
- Understanding quality-of-life patterns in long COVID: How Symptoms and socioeconomic conditions shape patient wellbeing.PloS one · 2026Observational
- Long COVID Longitudinal Symptoms Burden Clusters Within A National Community-Based Cohort.medRxiv : the preprint server for health sciences · 2025Article
- The Development and Initial Validation of the Memorial Symptom Assessment Scale-Long COVID (MSAS-LC): A Promising Tool for Measuring Long COVID.International journal of environmental research and public health · 2025Article
- Japanese nationwide survey to track the impact of long COVID over 3 years.Environmental health and preventive medicine · 2025Article
- Sustainable rural development: differentiated paths to achieve rural revitalization with case of Western China.Scientific reports · 2024Article
- Correction: Long COVID is not the same for everyone: a hierarchical cluster analysis of long COVID symptoms 9 and 12 months after SARS-CoV-2 test.BMC infectious diseases · 2024Article
Corrections and comments
- Erratum issued
Authors and funding
5 authors.
Funding
Abstract
backgroundIdentifying symptom clusters in Long COVID is necessary for developing effective therapies for this diverse condition and improving the quality of life of those affected by this heterogeneous condition. In this study, we aimed to identify and compare symptom clusters at 9 and 12 months after a SARS-CoV-2 positive test and describe each cluster regarding factors at infection.
methodsThis is a cross-sectional study with individuals randomly selected from the Portuguese National System of Epidemiological Surveillance (SINAVE) database. Individuals who had a positive RT-PCR SARS-CoV-2 test in August 2022 were contacted to participate in a telephonic interview approximately 9 and 12 months after the test. A hierarchical clustering analysis was performed, using Euclidean distance and Ward's linkage. Clustering was performed in the 35 symptoms reported 9 and 12 months after the SARS-CoV-2 positive test and characterised considering age, sex, pre-existing health conditions and symptoms at time of SARS-CoV-2 infection.
results552 individuals were included at 9 months and 458 at 12 months. The median age was 52 years (IQR: 40-64 years) and 59% were female. Hypertension and high cholesterol were the most frequently reported pre-existing health conditions. Memory loss, fatigue or weakness and joint pain were the most frequent symptoms reported 9 and 12 months after the positive test. Four clusters were identified at both times: no or minor symptoms; multi-symptoms; joint pain; and neurocognitive-related symptoms. Clusters remained similar in both times, but, within the neurocognitive cluster, memory loss and concentration issues increased in frequency at 12 months. Multi-symptoms cluster had older people, more females and more pre-existing health conditions at 9 months. However, at 12 months, older people and those with more pre-existing health conditions were in joint pain cluster.
conclusionsOur results suggest that Long COVID is not the same for everyone. In our study, clusters remained similar at 9 and 12 months, except for a slight variation in the frequency of symptoms that composed each cluster. Understanding Long COVID clusters might help identify treatments for this condition. However, further validation of the observed clusters and analysis of its risk factors is needed.
Indexed as
Identifiers
What OpenQuestion holds
Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.