How methodological pitfalls have created widespread misunderstanding about long COVID

Key messages:

  • The existing epidemiological research on long COVID has suffered from overly broad case definitions and a striking absence of control groups, which have led to distortion of risk.

  • The unintended consequences of this may include, but are not limited to, increased societal anxiety and healthcare spending, a failure to diagnose other treatable conditions misdiagnosed as long COVID and diversion of funds and attention from those who truly suffer from chronic conditions secondary to COVID-19.

  • Future research should include properly matched control groups, sufficient follow-up time after infection and internationally-established diagnostic or inclusion and exclusion criteria.

Source: Høeg TB, Ladhani S, Prasad V. How methodological pitfalls have created widespread misunderstanding about long COVID. BMJ Evid Based Med. 2023 Sep 25:bmjebm-2023-112338. doi: 10.1136/bmjebm-2023-112338. Epub ahead of print. PMID: 37748921. https://ebm.bmj.com/content/early/2023/08/10/bmjebm-2023-112338 (Full text)

Post-COVID cognitive dysfunction: current status and research recommendations for high risk population

Abstract:

Post-COVID cognitive dysfunction (PCCD) is a condition in which patients with a history of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, usually three months from the onset, exhibit subsequent cognitive impairment in various cognitive domains, and cannot be explained by an alternative diagnosis.

While our knowledge of the risk factors and management strategy of PCCD is still incomplete, it is necessary to integrate current epidemiology, diagnosis and treatment evidence, and form consensus criteria to better understand this disease to improve disease management. Identifying the risk factors and vulnerable population of PCCD and providing reliable strategies for effective prevention and management is urgently needed.

In this paper, we reviewed epidemiology, diagnostic markers, risk factors and available treatments on the disease, formed research recommendation framework for vulnerable population, under the background of post-COVID period.

Source: Quan M, Wang X, Gong M, Wang Q, Li Y, Jia J. Post-COVID cognitive dysfunction: current status and research recommendations for high risk population. Lancet Reg Health West Pac. 2023 Jul 5;38:100836. doi: 10.1016/j.lanwpc.2023.100836. PMID: 37457901; PMCID: PMC10344681. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10344681/ (Full text)

Epidemiology of post-COVID conditions beyond 1 year: a cross-sectional study

Abstract:

Objective: The aim of this study was to investigate the epidemiology of post-COVID conditions beyond 12 months and identify factors associated with the persistence of each condition.

Study design: This was a cross-sectional questionnaire-based survey.

Methods: We conducted the survey among patients who had recovered from COVID-19 and visited our institute between February 2020 and November 2021. Demographic and clinical data and data regarding the presence and duration of post-COVID conditions were obtained. We identified factors associated with the persistence of post-COVID conditions using multivariable linear regression analyses.

Results: Of 1148 surveyed patients, 502 completed the survey (response rate, 43.7%). Of these, 393 patients (86.4%) had mild disease in the acute phase. The proportion of participants with at least one symptom at 6, 12, 18, and 24 months after symptom onset or COVID-19 diagnosis was 32.3% (124/384), 30.5% (71/233), 25.8% (24/93), and 33.3% (2/6), respectively. The observed associations were as follows: fatigue persistence with moderate or severe COVID-19 (β = 0.53, 95% confidence interval [CI] = 0.06-0.99); shortness of breath with moderate or severe COVID-19 (β = 1.39, 95% CI = 0.91-1.87); cough with moderate or severe COVID-19 (β = 0.84, 95% CI = 0.40-1.29); dysosmia with being female (β = -0.57, 95% CI = -0.97 to -0.18) and absence of underlying medical conditions (β = -0.43, 95% CI = -0.82 to -0.05); hair loss with being female (β = -0.61, 95% CI = -1.00 to -0.22), absence of underlying medical conditions (β = -0.42, 95% CI = -0.80 to 0.04), and moderate or severe COVID-19 (β = 0.97, 95% CI = 0.41-1.54); depressed mood with younger age (β = -0.02, 95% CI = -0.04 to -0.004); and loss of concentration with being female (β = -0.51, 95% CI = -0.94 to -0.09).

Conclusions: More than one-fourth of patients after recovery from COVID-19, most of whom had had mild disease in the acute phase, had at least one symptom at 6, 12, 18, and 24 months after onset of COVID-19, indicating that not a few patients with COVID-19 suffer from long-term residual symptoms, even in mild cases.

Source: Morioka S, Tsuzuki S, Maruki T, Terada M, Miyazato Y, Kutsuna S, Saito S, Shimanishi Y, Takahashi K, Sanada M, Ashida S, Akashi M, Kuge C, Osanai Y, Tanaka K, Suzuki M, Hayakawa K, Ohmagari N. Epidemiology of post-COVID conditions beyond 1 year: a cross-sectional study. Public Health. 2023 Feb 13;216:39-44. doi: 10.1016/j.puhe.2023.01.008. Epub ahead of print. PMID: 36791649. https://www.sciencedirect.com/science/article/pii/S0033350623000173?via%3Dihub (Full text)

Risk of Long Covid in people infected with SARS-CoV-2 after two doses of a COVID-19 vaccine: community-based, matched cohort study

Abstract:

We investigated Long Covid incidence by vaccination status in a random sample of UK adults from April 2020 to November 2021. Persistent symptoms were reported by 9.5% of 3,090 breakthrough SARS-CoV-2 infections and 14.6% of unvaccinated controls (adjusted odds ratio 0.59, 95% CI: 0.50-0.69), emphasising the need for public health initiatives to increase population-level vaccine uptake.

Source: Daniel Ayoubkhani, Matthew L Bosworth, Sasha King, Koen B Pouwels, Myer Glickman, Vahé Nafilyan, Francesco Zaccardi, Kamlesh Khunti, Nisreen A Alwan, A Sarah Walker, Risk of Long Covid in people infected with SARS-CoV-2 after two doses of a COVID-19 vaccine: community-based, matched cohort study, Open Forum Infectious Diseases, 2022;, ofac464, https://doi.org/10.1093/ofid/ofac464 (Full text available as PDF file)

Detecting anti-SARS-CoV-2 antibodies in urine samples: A noninvasive and sensitive way to assay COVID-19 immune conversion

Abstract:

Serum-based ELISA (enzyme-linked immunosorbent assay) has been widely used to detect anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies. However, to date, no study has investigated patient urine as a biological sample to detect SARS-CoV-2 virus-specific antibodies. An in-house urine-based ELISA was developed using recombinant SARS-CoV-2 nucleocapsid protein.

The presence of SARS-CoV-2 antibodies in urine was established, with 94% sensitivity and 100% specificity for the detection of anti-SARS-CoV-2 antibodies with the urine-based ELISA and 88% sensitivity and 100% specificity with a paired serum-based ELISA. The urine-based ELISA that detects anti-SARS-CoV-2 antibodies is a noninvasive method with potential application as a facile COVID-19 immunodiagnostic platform, which can be used to report the extent of exposure at the population level and/or to assess the risk of infection at the individual level.

Source: Ludolf F, Ramos FF, Bagno FF, Oliveira-da-Silva JA, Reis TAR, Christodoulides M, Vassallo PF, Ravetti CG, Nobre V, da Fonseca FG, Coelho EAF. Detecting anti-SARS-CoV-2 antibodies in urine samples: A noninvasive and sensitive way to assay COVID-19 immune conversion. Sci Adv. 2022 May 13;8(19):eabn7424. doi: 10.1126/sciadv.abn7424. Epub 2022 May 13. PMID: 35559681; PMCID: PMC9106288. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9106288/ (Full text)

A global systematic analysis of the occurrence, severity, and recovery pattern of long COVID in 2020 and 2021

Abstract:

Importance: While much of the attention on the COVID-19 pandemic was directed at the daily counts of cases and those with serious disease overwhelming health services, increasingly, reports have appeared of people who experience debilitating symptoms after the initial infection. This is popularly known as long COVID.

Objective: To estimate by country and territory of the number of patients affected by long COVID in 2020 and 2021, the severity of their symptoms and expected pattern of recovery.

Design: We jointly analyzed ten ongoing cohort studies in ten countries for the occurrence of three major symptom clusters of long COVID among representative COVID cases. The defining symptoms of the three clusters (fatigue, cognitive problems, and shortness of breath) are explicitly mentioned in the WHO clinical case definition. For incidence of long COVID, we adopted the minimum duration after infection of three months from the WHO case definition. We pooled data from the contributing studies, two large medical record databases in the United States, and findings from 44 published studies using a Bayesian meta-regression tool. We separately estimated occurrence and pattern of recovery in patients with milder acute infections and those hospitalized. We estimated the incidence and prevalence of long COVID globally and by country in 2020 and 2021 as well as the severity-weighted prevalence using disability weights from the Global Burden of Disease study.

Results: Analyses are based on detailed information for 1906 community infections and 10526 hospitalized patients from the ten collaborating cohorts, three of which included children. We added published data on 37262 community infections and 9540 hospitalized patients as well as ICD-coded medical record data concerning 1.3 million infections. Globally, in 2020 and 2021, 144.7 million (95% uncertainty interval [UI] 54.8-312.9) people suffered from any of the three symptom clusters of long COVID. This corresponds to 3.69% (1.38-7.96) of all infections. The fatigue, respiratory, and cognitive clusters occurred in 51.0% (16.9-92.4), 60.4% (18.9-89.1), and 35.4% (9.4-75.1) of long COVID cases, respectively. Those with milder acute COVID-19 cases had a quicker estimated recovery (median duration 3.99 months [IQR 3.84-4.20]) than those admitted for the acute infection (median duration 8.84 months [IQR 8.10-9.78]). At twelve months, 15.1% (10.3-21.1) continued to experience long COVID symptoms.

Conclusions and relevance: The occurrence of debilitating ongoing symptoms of COVID-19 is common. Knowing how many people are affected, and for how long, is important to plan for rehabilitative services and support to return to social activities, places of learning, and the workplace when symptoms start to wane.

Source: Wulf Hanson S, Abbafati C, Aerts JG, Al-Aly Z, Ashbaugh C, Ballouz T, Blyuss O, Bobkova P, Bonsel G, Borzakova S, Buonsenso D, Butnaru D, Carter A, Chu H, De Rose C, Diab MM, Ekbom E, El Tantawi M, Fomin V, Frithiof R, Gamirova A, Glybochko PV, Haagsma JA, Javanmard SH, Hamilton EB, Harris G, Heijenbrok-Kal MH, Helbok R, Hellemons ME, Hillus D, Huijts SM, Hultström M, Jassat W, Kurth F, Larsson IM, Lipcsey M, Liu C, Loflin CD, Malinovschi A, Mao W, Mazankova L, McCulloch D, Menges D, Mohammadifard N, Munblit D, Nekliudov NA, Ogbuoji O, Osmanov IM, Peñalvo JL, Petersen MS, Puhan MA, Rahman M, Rass V, Reinig N, Ribbers GM, Ricchiuto A, Rubertsson S, Samitova E, Sarrafzadegan N, Shikhaleva A, Simpson KE, Sinatti D, Soriano JB, Spiridonova E, Steinbeis F, Svistunov AA, Valentini P, van de Water BJ, van den Berg-Emons R, Wallin E, Witzenrath M, Wu Y, Xu H, Zoller T, Adolph C, Albright J, Amlag JO, Aravkin AY, Bang-Jensen BL, Bisignano C, Castellano R, Castro E, Chakrabarti S, Collins JK, Dai X, Daoud F, Dapper C, Deen A, Duncan BB, Erickson M, Ewald SB, Ferrari AJ, Flaxman AD, Fullman N, Gamkrelidze A, Giles JR, Guo G, Hay SI, He J, Helak M, Hulland EN, Kereselidze M, Krohn KJ, Lazzar-Atwood A, Lindstrom A, Lozano R, Magistro B, Malta DC, Månsson J, Mantilla Herrera AM, Mokdad AH, Monasta L, Nomura S, Pasovic M, Pigott DM, Reiner RC, Reinke G, Ribeiro ALP, Santomauro DF, Sholokhov A, Spurlock EE, Walcott R, Walker A, Wiysonge CS, Zheng P, Bettger JP, Murray CJ, Vos T. A global systematic analysis of the occurrence, severity, and recovery pattern of long COVID in 2020 and 2021. medRxiv [Preprint]. 2022 May 27:2022.05.26.22275532. doi: 10.1101/2022.05.26.22275532. PMID: 35664995; PMCID: PMC9164454.  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9164454/ (Full text)

Obesity and lipid metabolism disorders determine the risk for development of long COVID syndrome: a cross-sectional study from 50,402 COVID-19 patients

Abstract:

Purpose: Metabolic disorders have been identified as major risk factors for severe acute courses of COVID-19. With decreasing numbers of infections in many countries, the long COVID syndrome (LCS) represents the next major challenge in pandemic management, warranting the precise definition of risk factors for LCS development.

Methods: We identified 50,402 COVID-19 patients in the Disease Analyzer database (IQVIA) featuring data from 1056 general practices in Germany. Multivariate logistic regression analysis was used to identify risk factors for the development of LCS.

Results: Of the 50,402 COVID-19 patients included into this analysis, 1,708 (3.4%) were diagnosed with LCS. In a multivariate regression analysis, we identified lipid metabolism disorders (OR 1.46, 95% CI 1.28-1.65, p < 0.001) and obesity (OR 1.25, 95% CI 1.08-1.44, p = 0.003) as strong risk factors for the development of LCS. Besides these metabolic factors, patients’ age between 46 and 60 years (compared to age ≤ 30, (OR 1.81 95% CI 1.54-2.13, p < 0.001), female sex (OR 1.33, 95% CI 1.20-1.47, p < 0.001) as well as pre-existing asthma (OR 1.67, 95% CI 1.39-2.00, p < 0.001) and depression (OR 1.27, 95% CI 1.09-1.47, p = < 0.002) in women, and cancer (OR 1.4, 95% CI 1.09-1.95, p = < 0.012) in men were associated with an increased likelihood of developing LCS.

Conclusion: Lipid metabolism disorders and obesity represent age-independent risk factors for the development of LCS, suggesting that metabolic alterations determine the risk for unfavorable disease courses along all phases of COVID-19.

Source: Loosen SH, Jensen BO, Tanislav C, Luedde T, Roderburg C, Kostev K. Obesity and lipid metabolism disorders determine the risk for development of long COVID syndrome: a cross-sectional study from 50,402 COVID-19 patients. Infection. 2022 Mar 30:1–6. doi: 10.1007/s15010-022-01784-0. Epub ahead of print. PMID: 35355237; PMCID: PMC8966865. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8966865/ (Full text)

Covid-19: Vaccinated people are less likely to get long covid, review finds

People who had been fully vaccinated against covid-19 were around half as likely to develop long covid symptoms as people who had received only one vaccine dose or were unvaccinated, the UK Health Security Agency has said.1

The agency conducted a rapid review of evidence, including 15 UK and international studies up to January 2022. Being vaccinated was defined as having two doses of the Pfizer-BioNTech, Oxford-AstraZeneca, or Moderna vaccine or one dose of the Janssen vaccine.

The review found that vaccine effectiveness against most post-covid symptoms in adults was highest in people over 60 and lowest in those aged 19 to 35.

Around 2% of the UK population have reported symptoms of long covid (or “post-covid syndrome”), which can last for more than four weeks after the initial SARS-CoV-2 infection. The most common symptoms are fatigue, shortness of breath, and muscle or joint pain.

Read the rest of this article HERE.

Source: Mahase E. Covid-19: Vaccinated people are less likely to get long covid, review finds. BMJ. 2022 Feb 16;376:o407. doi: 10.1136/bmj.o407. PMID: 35172970. https://www.bmj.com/content/376/bmj.o407 (Full text)

Long COVID: post-acute sequelae of COVID-19 with a cardiovascular focus

Abstract:

Emerging as a new epidemic, long COVID or post-acute sequelae of coronavirus disease 2019 (COVID-19), a condition characterized by the persistence of COVID-19 symptoms beyond 3 months, is anticipated to substantially alter the lives of millions of people globally. Cardiopulmonary symptoms including chest pain, shortness of breath, fatigue, and autonomic manifestations such as postural orthostatic tachycardia are common and associated with significant disability, heightened anxiety, and public awareness. A range of cardiovascular (CV) abnormalities has been reported among patients beyond the acute phase and include myocardial inflammation, myocardial infarction, right ventricular dysfunction, and arrhythmias.

Pathophysiological mechanisms for delayed complications are still poorly understood, with a dissociation seen between ongoing symptoms and objective measures of cardiopulmonary health. COVID-19 is anticipated to alter the long-term trajectory of many chronic cardiac diseases which are abundant in those at risk of severe disease.

In this review, we discuss the definition of long COVID and its epidemiology, with an emphasis on cardiopulmonary symptoms. We further review the pathophysiological mechanisms underlying acute and chronic CV injury, the range of post-acute CV sequelae, and impact of COVID-19 on multiorgan health. We propose a possible model for referral of post-COVID-19 patients to cardiac services and discuss future directions including research priorities and clinical trials that are currently underway to evaluate the efficacy of treatment strategies for long COVID and associated CV sequelae.

Source: Raman B, Bluemke DA, Lüscher TF, Neubauer S. Long COVID: post-acute sequelae of COVID-19 with a cardiovascular focus. Eur Heart J. 2022 Feb 18:ehac031. doi: 10.1093/eurheartj/ehac031. Epub ahead of print. PMID: 35176758. https://academic.oup.com/eurheartj/advance-article/doi/10.1093/eurheartj/ehac031/6529562 (Full text)