Systematic Review of the Prevalence of Long COVID

Abstract

Background Long Covid occurs in those infected with SARSCoV2 whose symptoms persist or develop beyond the acute phase. We conducted a systematic review to determine the prevalence of persistent symptoms, functional disability or pathological changes in adults or children at least 12 weeks post-infection. Methods We searched key registers and databases from 1st January 2020 to 2nd November 2021, limited to publications in English and studies with at least 100 participants. Studies where all participants were critically ill were excluded. Long Covid was extracted as prevalence of at least one symptom or pathology, or prevalence of the most common symptom or pathology, at 12 weeks or later. Heterogeneity was quantified in absolute terms and as a proportion of total variation and explored across pre-defined subgroups (PROSPERO ID CRD42020218351). Results 120 studies in 130 publications were included. Length of follow-up varied between 12 weeks - 12 months. Few studies had low risk of bias. All complete and subgroup analyses except one had I2 ≥ 90%, with prevalence of persistent symptoms range of 0% - 93% (pooled estimate (PE) 42.1%, 95% prediction interval (PI): 6.8% to 87.9%). Studies using routine healthcare records tended to report lower prevalence (PE 13.6%, PI: 1.2% to 68%) of persistent symptoms/pathology than self-report (PE 43.9%, PI: 8.2% to 87.2%). However, studies systematically investigating pathology in all participants at follow up tended to report the highest estimates of all three (PE 51.7%, PI: 12.3% to 89.1%). Studies of hospitalised cases had generally higher estimates than community-based studies. Conclusions The way in which Long Covid is defined and measured affects prevalence estimation. Given the widespread nature of SARSCoV2 infection globally, the burden of chronic illness is likely to be substantial even using the most conservative estimates.

Effects of the COVID-19 pandemic on people experiencing incarceration: a systematic review

“…A lack of long-duration longitudinal/cohort studies is a contributory reason for this. A systematic review of long COVID prevalence in the general population noted a pooled estimate of prevalence between 13.6% and 43.9%, depending on definition and method of measurement 86. The review also noted increased prevalence in hospitalised patients 86.…”

“…A systematic review of long COVID prevalence in the general population noted a pooled estimate of prevalence between 13.6% and 43.9%, depending on definition and method of measurement 86. The review also noted increased prevalence in hospitalised patients 86. Given the increased hospitalisation rates and poorer COVID-19 outcomes evident in PEI, long COVID burden in PEI is likely to be substantial.…”

Reengineering a machine learning phenotype to adapt to the changing COVID-19 landscape: A study from the N3C and RECOVER consortia

“…With the lack of a consensus clinical definition of Long COVID, 20 assessment of the true accuracy of algorithms like ours is challenging. Moreover, the lack of a consistent estimate for Long COVID's prevalence 21 makes it difficult to determine an appropriate model threshold using real-world evidence. Assessing performance using the U09.9 label as ground truth is the most readily available option, but the inconsistency of the code's use by providers and its late availability 4 mean that many patients with Long COVID lack the label.…”

Long COVID as a functional somatic symptom disorder caused by abnormally precise prior expectations during Bayesian perceptual processing: A new hypothesis and implications for pandemic response

“…51,69,70 Another systematic review found the risk difference (95% prediction intervals) for Long-COVID compared to controls was 13.9% (−16.2, 43.9), compared to controls in community-based samples 10.1% (−12.7, 32.8), and compared to controls in community-based samples assessed as at low risk of bias 4.8% (−13.2, 22.7). 71 Among COVID-19 cases, risk factors for Long-COVID in systematic reviews included female gender, 5,[7][8][9]41,42,45,72 dyspnea in the acute phase or asthma/chronic-lung-disease/ chronic-dyspnea, 5,41,42,72 previous psychiatric diagnosis (including prepandemic psychological distress), 5,8,41,72 severity of acute COVID-19 (including number of acute symptoms 42 and hospitalization, 7,42,43,72 especially in intensive care), 5,[7][8][9]42,43,72 and underlying comorbidity. 8,42,45,72 Individual studies have also emphasized psychiatric diagnoses as risk factors, for example, preexisting fibromyalgia, anxiety, depression, migraine, irritable bowel syndrome (IBS), eating disorder, or back pain; 50 and preexisting diagnosis of depression or anxiety.…”