Characterizing long COVID in an international cohort: 7 months of symptoms and their impact
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Abstract
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SciScore for 10.1101/2020.12.24.20248802: (What is this?)
Please note, not all rigor criteria are appropriate for all manuscripts.
Table 1: Rigor
Institutional Review Board Statement Consent: All respondents gave digital informed consent at the start of the survey.
IRB: This study was approved by the UCL Research Ethics Committee [16159.002], and Oregon Health and Science University, Portland, Oregon, USA, with UCL serving as primary site.Randomization not detected. Blinding not detected. Power Analysis not detected. Sex as a biological variable not detected. Table 2: Resources
No key resources detected.
Results from OddPub: We did not detect open data. We also did not detect open code. Researchers are encouraged to share open data when possible (see Nature blog).
Results from LimitationRecognizer: We detected the following sentences addressing …SciScore for 10.1101/2020.12.24.20248802: (What is this?)
Please note, not all rigor criteria are appropriate for all manuscripts.
Table 1: Rigor
Institutional Review Board Statement Consent: All respondents gave digital informed consent at the start of the survey.
IRB: This study was approved by the UCL Research Ethics Committee [16159.002], and Oregon Health and Science University, Portland, Oregon, USA, with UCL serving as primary site.Randomization not detected. Blinding not detected. Power Analysis not detected. Sex as a biological variable not detected. Table 2: Resources
No key resources detected.
Results from OddPub: We did not detect open data. We also did not detect open code. Researchers are encouraged to share open data when possible (see Nature blog).
Results from LimitationRecognizer: We detected the following sentences addressing limitations in the study:Limitations: There are several limitations to this study. First, the retrospective nature of the study exposes the possibility of recall bias. Second, as the survey was distributed in online support groups, there exists a sampling bias toward Long COVID patients who joined support groups and were active participants of the groups at the time the survey was published. Additionally, despite eight translations and inclusive outreach efforts, the demographics were strongly skewed towards English speaking (91.9%), white (85.3%), and higher socioeconomic status (see Figure S1). In future studies, more outreach and partnerships with diverse support groups, low-income communities, and communities of color can be established to counter sampling bias. Moreover, the study required respondents to have stable internet and email addresses, which may have excluded participants who lacked access and/or had low digital literacy. Lastly, the effort to complete the survey may have deterred some respondents who experienced cognitive dysfunction, or were no longer ill and did not have enough incentives to participate. Due to these limitations, we suggest that the results laid forth be considered only in this context, and caution that extrapolation to the entire Long COVID population may not be valid. Implications: Research by the United Kingdom’s Office of National Statistics estimates that 21% of people who were infected with SARS-CoV-2 still experience symptoms at five weeks, a number which inc...
Results from TrialIdentifier: No clinical trial numbers were referenced.
Results from Barzooka: We did not find any issues relating to the usage of bar graphs.
Results from JetFighter: We did not find any issues relating to colormaps.
Results from rtransparent:- Thank you for including a conflict of interest statement. Authors are encouraged to include this statement when submitting to a journal.
- Thank you for including a funding statement. Authors are encouraged to include this statement when submitting to a journal.
- No protocol registration statement was detected.
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Our take
This study, available as a preprint and thus not yet peer reviewed, details manifestations of “Long COVID” in a sample of 3,762 individuals (mostly white and female) who were recruited from 56 countries from patient support groups and social media, and who self-reported symptom prevalence and severity over time. Of all respondents, only 27% reported they had received a laboratory-confirmed COVID-19 diagnosis. The majority (65%) of participants experienced symptoms for more than 6 months, with fatigue, shortness of breath, and cognitive dysfunction as some of the most persistent and debilitating symptoms. However, results should be interpreted with caution, since all data were self-reported from a highly selected group of individuals who are not representative of the general population with confirmed SARS-CoV-2 …
Our take
This study, available as a preprint and thus not yet peer reviewed, details manifestations of “Long COVID” in a sample of 3,762 individuals (mostly white and female) who were recruited from 56 countries from patient support groups and social media, and who self-reported symptom prevalence and severity over time. Of all respondents, only 27% reported they had received a laboratory-confirmed COVID-19 diagnosis. The majority (65%) of participants experienced symptoms for more than 6 months, with fatigue, shortness of breath, and cognitive dysfunction as some of the most persistent and debilitating symptoms. However, results should be interpreted with caution, since all data were self-reported from a highly selected group of individuals who are not representative of the general population with confirmed SARS-CoV-2 infection.
Study design
retrospective-cohort
Study population and setting
This preprint provides extensive data on the long-term (through 7 months) experience and recovery process of individuals with confirmed or suspected COVID-19, using data collected from online surveys administered from September 6 to November 25, 2020. Survey links were disseminated over social media and through COVID-19 patient support groups. The study included 3,762 adults (79% women, 85% white, age range: 30-60 years) from 56 countries (41% US, 35% UK and Ireland), who self-reported symptoms consistent with COVID-19, and whose illness lasted longer than 28 days (with symptom onset occurring between December 2019 and May 2020). Participants were not required to have diagnostic or antibody testing for SARS-CoV-2. Participants reported symptom severity (none, very mild, mild, moderate, severe, very severe) and presence of symptoms during specific time intervals after initial symptom onset (weekly intervals for first 4 weeks, then monthly intervals through month 7) for 66 symptoms.
Summary of main findings
Among the 3,762 participants, 2,330 were ever tested for SARS-CoV-2; only 1,020 had a positive RT-PCR, antigen, or antibody test. Symptom prevalence and trends were similar between those who ever tested positive for SARS-CoV-2 and those who did not; loss of smell or taste was more common among those who tested positive. 3,505 (93%) participants were still experiencing symptoms at the time of survey completion, including 2,454 respondents who had experienced symptoms for at least 6 months, and 257 recovered. Among those with symptoms lasting more than 3 months, symptom peak occurred in month 2 (mean number of symptoms reported=17.2, 95% CI: 16.5-17.8). When patients were asked to list their most debilitating symptoms, the top three responses were fatigue, breathing issues, and cognitive dysfunction. The most prevalent and persistent symptom by week 28 was fatigue with a prevalence around 80% (all symptom prevalence estimates were conditional on no recovery having yet occurred by a given time); followed by brain fog/memory issues and other neurological sensations (~60%); headaches, insomnia, shortness of breath, palpitations, and tachycardia each had a prevalence near 40% though week 28. The authors identified 3 clusters of symptoms by the trajectory of their self-reported prevalence over time. Those in cluster 1 (including diarrhea, loss of appetite, vomiting, runny nose, sore throat, dry cough, and fever) were most common during early illness onset and then decreased over time. Those in cluster 2 (including chest pain/tightness, abdominal pain, muscle aches, confusion, headaches, chills, and fatigue) gradually increased during the first few weeks with a slow decrease or no change over time. Those in cluster 3 (including palpitations, dermatologic effects, constipation, hearing/vision alterations, joint pain, brain fog, and memory issues) increased over the first two months and then persisted. Only 27% of unrecovered patients and 49% of recovered patients reported working as many hours as they had done prior to becoming ill.
Study strengths
This study included a relatively large number of participants and collected extensive data on a wide range of symptom data, including severity and trends over time.
Limitations
This a preprint that has not yet been peer reviewed, so all findings should be interpreted with caution. All data were based on self-reported symptoms and COVID-19 testing results, which are subject to the standard limitations of self-reported data. Importantly, participants self-selected into the study, which limits generalizability and may induce a sampling bias toward individuals who actively sought support groups for their condition. The sample is primarily female and primarily white, which is generally not representative of the larger population of individuals with COVID-19. Persistent symptom trends should not be interpreted as prevalences among all individuals who had COVID-19, but rather represent the experience of a highly selected group of individuals who had symptoms lasting more than 28 days and elected to participate in the online survey. The majority of participants did not receive a positive RT-PCR, antigen, or antibody test for COVID-19, so it is possible that other conditions contributed to the symptoms experienced.
Value added
This is the largest known report of patients experiencing symptoms consistent with “long COVID,” with detailed data on duration and severity of symptoms in the months following confirmed or suspected COVID-19.
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SciScore for 10.1101/2020.12.24.20248802: (What is this?)
Please note, not all rigor criteria are appropriate for all manuscripts.
Table 1: Rigor
Institutional Review Board Statement All respondents gave digital informed consent at the start of the survey. Randomization not detected. Blinding not detected. Power Analysis not detected. Sex as a biological variable The majority of respondents were women (78.9%, significantly more than other genders, p < 0.001, chi-squared test), white (85.3%, p < 0.001, chi-squared test), and between the ages of 30 and 60 (33.7% between ages 40-49, 27.1% ages 50-59, 26.1% 30-39). Table 2: Resources
Software and Algorithms Sentences Resources For the sensorimotor textual input questions, which asked which body part was affected, natural language processing was used in Python. SciScore for 10.1101/2020.12.24.20248802: (What is this?)
Please note, not all rigor criteria are appropriate for all manuscripts.
Table 1: Rigor
Institutional Review Board Statement All respondents gave digital informed consent at the start of the survey. Randomization not detected. Blinding not detected. Power Analysis not detected. Sex as a biological variable The majority of respondents were women (78.9%, significantly more than other genders, p < 0.001, chi-squared test), white (85.3%, p < 0.001, chi-squared test), and between the ages of 30 and 60 (33.7% between ages 40-49, 27.1% ages 50-59, 26.1% 30-39). Table 2: Resources
Software and Algorithms Sentences Resources For the sensorimotor textual input questions, which asked which body part was affected, natural language processing was used in Python. Pythonsuggested: (IPython, RRID:SCR_001658)Results from OddPub: We did not detect open data. We also did not detect open code. Researchers are encouraged to share open data when possible (see Nature blog).
Results from LimitationRecognizer: We detected the following sentences addressing limitations in the study:
Limitations There are several limitations to this study. First, the retrospective nature of the study exposes the possibility of recall bias. Second, as the survey was distributed in online support groups, there exists a sampling bias toward Long COVID patients who joined support groups and were active participants of the groups at the time the survey was published. Additionally, despite eight translations and inclusive outreach efforts, the demographics were strongly skewed towards English speaking (91.9%), white (85.3%), and higher socioeconomic status (see Figure S1). In future studies, more outreach and partnerships with diverse support groups, low-income communities, and communities of color can be established to counter sampling bias. Moreover, the study required respondents to have stable internet and email addresses, which may have excluded participants who lacked access and/or had low digital literacy. Lastly, the effort to complete the survey may have deterred some respondents who experienced cognitive dysfunction, or were no longer ill and did not have enough incentives to participate. Due to these limitations, we suggest that the results laid forth be considered only in this context, and caution that extrapolation to the entire Long COVID population may not be valid. Implications Research by the United Kingdom’s Office of National Statistics estimates that 21% of people who were infected with SARS-CoV-2 still experience symptoms at five weeks, a number which inclu...
Results from TrialIdentifier: No clinical trial numbers were referenced.
Results from Barzooka: We found bar graphs of continuous data. We recommend replacing bar graphs with more informative graphics, as many different datasets can lead to the same bar graph. The actual data may suggest different conclusions from the summary statistics. For more information, please see Weissgerber et al (2015).
Results from JetFighter: We did not find any issues relating to colormaps.
About SciScore
SciScore is an automated tool that is designed to assist expert reviewers by finding and presenting formulaic information scattered throughout a paper in a standard, easy to digest format. SciScore checks for the presence and correctness of RRIDs (research resource identifiers), and for rigor criteria such as sex and investigator blinding. For details on the theoretical underpinning of rigor criteria and the tools shown here, including references cited, please follow this link.
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