Symptoms and management of long COVID: A scoping review

How do people with long COVID utilize COVID-19 vaccination and rehabilitation services and what are their experiences with these services? results of a qualitative study with 48 participants from Germany

BACKGROUND

Studies estimate that at least 7.5% of adults are affected by long-term symptoms such as fatigue or cognitive impairment after the acute phase of COVID-19. COVID-19 vaccination may reduce the risk of long COVID. Rehabilitation can have a positive impact on recovery. This study aims to present the experiences of people with long COVID with COVID-19 vaccination and rehabilitation. Such research is important because perceptions of these measures can impact healthcare utilization and health status.

METHODS

48 adults with long COVID participated in this qualitative study, 25 of them in one-on-one interviews and 23 in focus groups. Participants were recruited via calls for participation on the websites and social media channels of two university hospitals and with the help of respondents' networks. The conversations were audio-recorded, transcribed, and analyzed using qualitative content analysis. Subsequently, the results were compared, interpreted, and discussed by scientific literature.

RESULTS

35 study participants reported that they had received a COVID-19 vaccination and 16 of them stated that they had utilized a rehabilitation service. These participants had varying experiences with COVID-19 vaccination and rehabilitation. Nine of them stated that they developed long COVID despite vaccination before COVID-19. Ten participants reported vaccine reactions, and two participants reported severe side effects. Two participants reported persistent deterioration of their long COVID symptoms after vaccination. This led to uncertainty about the safety, benefits, and handling of COVID-19 vaccination. However, most participants perceived the vaccine as effective regarding milder COVID-19 sequelae. Four participants felt their rehabilitation was helpful and four participants felt it was unhelpful. Two persons found the combination of inpatient rehabilitation and rehabilitation sport helpful.

CONCLUSIONS

Several implications can be derived from this study: (1) researchers should explore the effects of COVID-19 vaccination on long COVID symptoms; (2) vaccination campaigns should be more responsive to the perspectives of people with long COVID on vaccination; (3) care planners should build rehabilitation facilities specialized in long COVID; (4) rehabilitation providers should train their professionals regarding long COVID and develop rehabilitation programs tailored to different clinical pictures.

TRIAL REGISTRATION

German register for clinical trials DRKS00026007, 09 September 2021.

Traumatic Brain Injury in the Long-COVID Era

Major determinants of the biological background or reserve, such as age, biological sex, comorbidities (diabetes, hypertension, obesity, etc.), and medications (e.g., anticoagulants), are known to affect outcome after traumatic brain injury (TBI). With the unparalleled data richness of coronavirus disease 2019 (COVID-19; ∼375,000 and counting!) as well as the chronic form, long-COVID, also called post-acute sequelae SARS-CoV-2 infection (PASC), publications (∼30,000 and counting) covering virtually every aspect of the diseases, pathomechanisms, biomarkers, disease phases, symptomatology, etc., have provided a unique opportunity to better understand and appreciate the holistic nature of diseases, interconnectivity between organ systems, and importance of biological background in modifying disease trajectories and affecting outcomes. Such a holistic approach is badly needed to better understand TBI-induced conditions in their totality. Here, I briefly review what is known about long-COVID/PASC, its underlying-suspected-pathologies, the pathobiological changes induced by TBI, in other words, the TBI endophenotypes, discuss the intersection of long-COVID/PASC and TBI-induced pathobiologies, and how by considering some of the known factors affecting the person's biological background and the inclusion of mechanistic molecular biomarkers can help to improve the clinical management of TBI patients.

Parenting and Gender as Impact Factors for Social Participation, Quality of Life, and Mental Health in Long COVID

OBJECTIVES

This study aims to investigate the impact of gender and parental tasks on social participation, health-related quality of life (hrQoL), and mental health in persons with long COVID.

METHODS

A mixed-methods approach was followed including a cross-sectional web-based survey and semi-structured interviews. Multivariable linear regressions were used to quantify the effect of gender and parenting tasks on social participation, hrQoL, and mental health. Qualitative data from interviews with participants experiencing long COVID symptoms was analyzed using content analysis.

RESULTS

Data from 920 participants in the quantitative study and 25 participants in the qualitative study was analyzed. Parenting tasks were associated with increased impairments in family and domestic responsibilities in persons with long COVID compared to lower impairments in persons without long COVID (P = .02). The qualitative data indicate that coping with long COVID and pursuing parenting tasks limit participants' ability to perform leisure activities and attend social gatherings. In long COVID, men had higher anxiety symptoms than women, and in those without long COVID, the opposite was observed (P < .001). In the qualitative study, participants expressed feelings of dejection and pessimism about their future private, occupational, and health situations. No differences between the genders could be observed.

CONCLUSIONS

Long COVID is associated with impairments in family and domestic responsibilities in individuals who have parenting tasks. Among participants with long COVID, anxiety symptoms are higher in men than women.

Evolution of musculoskeletal symptoms in Long COVID syndrome: a lexical analysis to approach requirements for an interdisciplinary management

Long COVID syndrome is characterized by new, returning, or persistent symptoms after the initial SARS-CoV-2 infection. Among the potential long-term effects of COVID-19, several different musculoskeletal symptoms have been reported in many patients with an important impact on quality of life. The rehabilitation needs of Long COVID patients could be dynamic. However, to date there are no studies that have evaluated how the rehabilitation needs of patients with Long COVID syndrome have changed over time. We conducted a literature review to summarize the most recurrent manifestations of the Long COVID syndrome during the three years of the pandemic, as well as the evolution of musculoskeletal symptoms, through lexical analysis. This approach allowed us to investigate the literature, highlighting how the most used words to describe Long COVID symptoms and outcomes have changed over different periods. Our analysis showed an increasing involvement of the musculoskeletal system in Long COVID symptomatology, as evidenced by the progressive growth of fatigue and weakness symptoms over time. In addition, arthralgia has always been associated with Long COVID. The lexical analysis we conducted emphasizes the need for interdisciplinary management, as the symptoms reported are interconnected. Moreover, this novel approach highlights that the Long COVID syndrome can be interpreted as a dynamic entity requiring up-to-date rehabilitative interventions. The worldwide healthcare systems should be founded on multidisciplinary teams to guarantee early and comprehensive rehabilitation to reduce the socio-sanitary burden associated with this syndrome.

Post-discharge Healthcare Usage and Costs From March 2020 Through the Omicron Surge for Individuals Hospitalized With COVID-19

INTRODUCTION

Despite the rise of post-COVID care centers, few studies exist that quantify the burden of patient healthcare usage and hospital costs after COVID-19 hospitalization. It is essential to target post-COVID follow-up care to the individuals who need it most, such that costs and emergencies are minimized and health and appointment attendance are optimized.

METHODS

This was a retrospective cohort comparison among four groups of 50 patients (200 total). Post-discharge healthcare utilization metrics were collected for individuals hospitalized with COVID-19 during the first four surges of the pandemic to compare how patients receive and seek care in the year after they contract COVID-19. A brief cost analysis was done to identify high-usage groups that could be targeted for intervention to decrease post-COVID hospitalization emergencies and burden.

RESULTS

Patients hospitalized during the Omicron surge were scheduled for the most specialist visits on average, significantly higher than average specialist visits in the Delta surge (p<0.05). The Delta surge had significantly less specialty care and missed visits than all other surges (p<0.05) and less primary care than the first two surges of the pandemic (p<0.05). Patients with type 2 diabetes and asthma had the highest overall costs (p<0.05). Females and Hispanic patients had the highest specialty and ED costs (p<0.05).

CONCLUSION

Each surge reflects a different approach to post-COVID care, with the Omicron surge demonstrating the heaviest usage overall, particularly with specialty visits. Increased specialty referrals may exacerbate rates of missed appointments, while primary care may lower emergency visits. Future approaches to post-COVID care design should identify patients at risk for emergencies and reinstate them with primary care.

Living with pulmonary sequelae of COVID-19 and the implications for clinical nursing practice: A qualitative systematised review

AIM

To synthesise qualitative research on pulmonary sequelae of COVID-19 and identify patient needs and experiences to develop nursing care strategies.

BACKGROUND

Qualitative research on long COVID by subtype has not yet occurred. As pulmonary sequelae constitute a serious long COVID subtype, exploring patient experience and needs can generate knowledge to guide nursing practice.

DESIGN

Systematised review methodology utilised on a purposive sample of published articles and reported using the PRISMA guidelines and checklists. Searched MEDLINE, Cumulative Index to Nursing and Allied Health, and Google Scholar, for English or French articles published from February 2020 to June 2022; qualitative research with adults recovering from COVID-19 with evidence of pulmonary sequelae.

METHODS

Established principles for data extraction followed related to data reduction, data presentation, data comparison, and conclusion formulation and verification. Analysis was informed by Thorne's Interpretive Description and extended with Meleis' transitions theory, Mishel's uncertainty in illness theory and Moore et al.'s holistic theory of unpleasant symptoms. The quality of included studies was assessed Joanna Briggs Institute critical appraisal tool for qualitative research.

RESULTS

Four articles with six pooled participants provided data to yield three main themes: (1) a novel health-illness transition, (2) lung injury and pulmonary fibrosis as antecedent to illness uncertainty, (3) and pulmonary symptoms that are compounded by fatigue and weakness.

CONCLUSION

Pulmonary sequelae of COVID-19 confers a unique health-illness transition, uncertainties and symptoms that can be addressed by theory informed nursing practice.

RELEVANCE TO CLINICAL PRACTICE

Advocacy, optimising the nurse-patient relationship, offering up-to-date information and addressing uncertainty may help patients cope with pulmonary sequelae, a complex subtype of long COVID with important considerations for clinical nursing care. Despite a lack of evidence-informed clinical pathways, nurses can support patients to understand novel treatments, support discharge planning and acknowledge the synergistic nature of pulmonary symptoms and fatigue to support health-illness transitions.

NO PATIENT OR PUBLIC CONTRIBUTION

This article involved analysis of previously published works.

"There is no one who helps you with it": experiences of people with long COVID regarding medical care, therapeutic measures, and barriers in the German healthcare system: results of a qualitative study with four focus groups

BACKGROUND

Many people experience long-term symptoms such as fatigue, cognitive problems, or shortness of breath after an acute infection with COVID-19. This emerging syndrome, known as long COVID, is new and complex in many aspects. This study aims to collect the experiences of people with long COVID with ambulatory healthcare structures.

METHODS

Four focus groups were conducted with a total of 23 adults with long COVID in June and July 2022. These discussions were audio-recorded, subsequently transcribed, and analyzed using the qualitative content analysis of Mayring and Kuckartz.

RESULTS

Fourteen out of 19 participants who had a primary care encounter regarding their long COVID symptoms did not perceive it as helpful. Many respondents reported that their general practitioners did not take their long COVID symptoms seriously and did not refer them to specialists or made therapeutic recommendations. However, some participants reported that they were prescribed non-pharmaceutical therapies (e.g., group meetings supported by psychotherapists, occupational therapy, etc.) that improved their condition. 14 of 23 respondents perceived care barriers such as providers' lack of awareness of long COVID, poor access to specialists, a lack of specialized care (e.g., long COVID clinics), or high bureaucratic hurdles for specific healthcare services. To improve medical care, participants suggested campaigns to raise awareness of long COVID among healthcare providers and the general population, increase research and government investments regarding the development of treatment structures for long COVID, expanding existing therapeutic services, and establishing one-stop shops for integrated specialist healthcare for people with long COVID.

CONCLUSIONS

Several implications for healthcare professionals and policymakers can be derived from this study: (1) general practitioners should take the symptoms of long COVID seriously, assume a care coordinating role, make referrals, and establish contact with long COVID clinics; (2) care planners should focus on developing interprofessional evidence-based care and treatment approaches for long COVID; (3) existing care structures such as long COVID outpatient clinics should be expanded. The overarching goal must be to develop consistent guidelines for long COVID diagnosis, care, and treatment.

TRIAL REGISTRATION

The study is registered in the German register for clinical trials (DRKS00026007, first registration on 09/09/2021).

The Assessment of Post-COVID Fatigue and Its Relationship to the Severity and Duration of Acute COVID Illness

Emerging data suggests that COVID-19 is associated with fatigue well beyond the acute illness period. The present analysis aimed to: (1) characterize the prevalence and incidence of high fatigue at baseline and follow-up; (2) examine the impact of COVID-19 diagnosis on fatigue level following acute illness; and (3) examine the impact of acute COVID-19 symptom severity and duration on fatigue at follow-up. Subjects (n = 1417; 81.0% female; 83.3% White; X¯age = 43.6 years) completed the PROMIS-Fatigue during the initial wave of the pandemic at baseline (April-June 2020) and 9-month follow-up (January-March 2021). A generalized linear model (binomial distribution) was used to examine whether COVID-19 positivity, severity, and duration were associated with higher fatigue level at follow-up. Prevalence of high fatigue at baseline was 21.88% and 22.16% at follow-up, with 8.12% new cases at follow-up. Testing positive for COVID-19 was significantly associated with higher fatigue at follow-up. COVID-19 symptom duration and severity were significantly associated with increased fatigue at follow-up. COVID-19 symptom duration and severity during acute illness may precipitate longer-term fatigue, which could have implications for treatment planning and future research. Future studies should further evaluate the relationship between symptom severity, duration, and fatigue.

Prevalence of Long COVID Symptoms Related to SARS-CoV-2 Strains

BACKGROUND

Few studies have assessed the differences of patterns of Long COVID (L-COVID) with regards to the pathogenetic SARS-CoV-2 strains.

OBJECTIVES

To investigate the relationship between demographic and clinical characteristics of acute phase of infection and the persistence of L-COVID symptoms and clinical presentation across different SARS-CoV-2 strains.

METHODS

In this observational-multicenter study we recorded all demographic and clinical characteristics, severity of infection, presence/persistence of symptoms of fatigue, dyspnoea and altered quality of life (QoL) at baseline and after 6 months, in a sample of Italian patients from Liguria between March 2020 and March 2022.

RESULTS

308 patients (mean age 63.2 years; 55.5% men) with previous COVID were enrolled. Obese patients were 21.2% with a significant difference in obesity prevalence across the second and third wave (p = 0.012). Treatment strategies differed between waves (p < 0.001): more patients required invasive mechanical ventilation in the first wave, more patients were treated with high-flow nasal cannula/non-invasive ventilation in the in the second and more patients were treated with oxygen-therapy in the fourth wave. At baseline, a high proportion of patients were symptomatic (dyspnoea and fatigue), with impairment in some QoL indicators. A higher prevalence of patients with pain, were seen in the first wave compared to later infections (p = 0.01). At follow-up, we observed improvement of dyspnoea, fatigue and some dimensions of QoL scale evaluation such as mobility, usual activities, pain evaluations; instead there was no improvement in remaining QoL scale indicators (usual care and anxiety-depression).

CONCLUSIONS

There were no significant differences in the prevalence of the most frequent L-COVID symptoms, except for QoL pain domain that was especially associated with classical variant. Our results show substantial impact on social and professional life and usual care activities. These findings highlight the importance of multidisciplinary post COVID follow-up care including mental health support and rehabilitation program.

Fatigue outcomes following COVID-19: a systematic review and meta-analysis

OBJECTIVES

Fatigue is a pervasive clinical symptom in coronaviruses and may continue beyond the acute phase, lasting for several months or years. This systematic review and meta-analysis aimed to incorporate the current evidence for postinfection fatigue among survivors of SARS-CoV-2 and investigate associated factors.

METHODS

Embase, PsyINFO, Medline, CINAHL, CDSR, Open Grey, BioRxiv and MedRxiv were systematically searched from January 2019 to December 2021. Eligible records included all study designs in English. Outcomes were fatigue or vitality in adults with a confirmed diagnosis of SARS-CoV-2 measured at >30 days post infection. Non-confirmed cases were excluded. JBI risk of bias was assessed by three reviewers. Random effects model was used for the pooled proportion with 95% CIs. A mixed effects meta-regression of 35 prospective articles calculated change in fatigue overtime. Subgroup analyses explored specific group characteristics of study methodology. Heterogeneity was assessed using Cochran's Q and I2 statistic. Egger's tests for publication bias.

RESULTS

Database searches returned 14 262 records. Following deduplication and screening, 178 records were identified. 147 (n=48 466 participants) were included for the meta-analyses. Pooled prevalence was 41% (95% CI: 37% to 45%, k=147, I2=98%). Fatigue significantly reduced over time (-0.057, 95% CI: -107 to -0.008, k=35, I2=99.3%, p=0.05). A higher proportion of fatigue was found in studies using a valid scale (51%, 95% CI: 43% to 58%, k=36, I2=96.2%, p=0.004). No significant difference was found for fatigue by study design (p=0.272). Egger's test indicated publication bias for all analyses except valid scales. Quality assessments indicated 4% at low risk of bias, 78% at moderate risk and 18% at high risk. Frequently reported associations were female gender, age, physical functioning, breathlessness and psychological distress.

CONCLUSION

This study revealed that a significant proportion of survivors experienced fatigue following SARS-CoV-2 and their fatigue reduced overtime. Non-modifiable factors and psychological morbidity may contribute to ongoing fatigue and impede recovery.

PROSPERO REGISTRATION NUMBER

CRD42020201247.

How do long COVID patients perceive their current life situation and occupational perspective? Results of a qualitative interview study in Germany

Introduction

Many people experience persistent or new-onset symptoms such as fatigue or cognitive problems after an acute infection with COVID-19. This phenomenon, known as long COVID, impacts physical and mental wellbeing, and may affect perceived quality of life and occupational perspectives likewise. The aim of this study is to gain a deeper understanding of how people with long COVID experience health-related restrictions in their daily life and their occupational situation, and to identify key challenges they face.

Methods

Guided qualitative interviews were conducted with 25 people with long COVID. The interviews were transcribed according to Dresing/Pehl and Kuckartz and analyzed using qualitative content analysis. Afterward, a systematic comparison of the data and a reflection under consideration of lifeworld-theoretical approaches (Berger and Luckmann) were carried out.

Results

The interviews revealed that many participants have severe symptoms which strongly impair them in perform daily and work-related activities, and in their personal interests. Many interviewees already reach their stress limit during routine household activities or childcare. Of the 25 participants, 19 experienced limitations in pursuing leisure activities, and 10 of the 23 interviewees with jobs reported being on sick leave for several months. Several respondents who had vocational reintegration are still affected by ongoing symptoms that affect their work performance considerably. This leads to uncertainty, role conflicts, a decline in social contacts, and decreased incomes, which contribute to an impairment in their quality of life.

Conclusions

This study shows the huge need for specific support for people with long COVID in different areas of life. To prevent people with long COVID from finding themselves in social and economic precarity, decision-makers should develop strategies to systematically support them in their sustainable reintegration into the workforce. The focus should be on creating long COVID-sensitive workplaces, compensating for decreased incomes, and improving access to relief services such as vocational reintegration. We argue, that a shift of perspectives is necessary and that long COVID should be considered rather as a “social disease” with considerably impairments in the social life of those affected.

Trial registration

The study is registered in the German register for clinical trials (DRKS00026007).

The ambulatory care of patients with post-acute sequelae of COVID-19

Background

There is an increasing number of patients that do not make a rapid or full recovery from a SARS-CoV-2 infection, the Coronavirus Disease 2019 (COVID-19) and suffer from the so-called “long-COVID” or post-acute sequelae of COVID-19 (PASC). The long-term implications for health services are expected to be substantial. The objective of this analysis was to estimate the utilization of outpatient services from primary and secondary care. Further, we evaluated the multidisciplinary ambulatory care management of PASC patients in Germany.

Methods

All members of the Physician network “MEDI Baden-Württemberg e.V.”, i.e., 1,263 primary care physicians (PCPs) and 1,772 specialists working in secondary care were invited to participate in a questionnaire surveying routine data regarding the general care situation at the physician practice level of patients suffering from PASC. Bivariate analyses were applied to consider potential differences between primary and secondary care.

Results

In total, 194 physicians participated in this survey (response rates of 9.6% (primary care) and 4.1% (secondary care). On average, each physician treated 31.9 PASC patients. Most PASC patients (61.2%) had three or more long-COVID symptoms. On average, 10.6 PASC patients visited a physicians’ practice per quarter. The additional consulting effort for treating PASC patients was 34.1 min (median: 20 min) and higher in primary care. Most PCPs (71.1%) integrated secondary care in the treatment of their PASC patients. Less than half of the PASC patients (42.0%) sought secondary care with a referral from primary care. 5.7 patients visited the physicians’ practices per week, who were concerned about suffering from PASC without any following medical confirmation. This caused an average additional effort for the physicians of 17.5 min per visit. There were no differences between rural and urban areas.

Conclusion

Our results reveal that there is a substantial additional consulting effort for treating PASC patients that is especially high in primary care. The additional consulting effort results from the consultation of a particular high number of patients that are concerned about suffering from PACS without a following medical confirmation. To guarantee a high quality and adequate provision of care for a potentially further increasing number of concerned patients, the ambulatory health services should be strengthened and adequately compensated.

Post-acute COVID-19 symptom risk in hospitalized and non-hospitalized COVID-19 survivors: A systematic review and meta-analysis

Background

Post-acute coronavirus disease 2019 (COVID-19) symptoms occurred in most of the COVID-19 survivors. However, few studies have examined the issue of whether hospitalization results in different post-acute COVID-19 symptom risks. This study aimed to compare potential COVID-19 long-term effects in hospitalized and non-hospitalized COVID-19 survivors.

Methods

This study is designed as a systematic review and meta-analysis of observational studies. A systematic search of six databases was performed for identifying articles published from inception until April 20th, 2022, which compared post-acute COVID-19 symptom risk in hospitalized and non-hospitalized COVID-19 survivors using a predesigned search strategy included terms for SARS-CoV-2 (eg, COVID, coronavirus, and 2019-nCoV), post-acute COVID-19 Syndrome (eg, post-COVID, post COVID conditions, chronic COVID symptom, long COVID, long COVID symptom, long-haul COVID, COVID sequelae, convalescence, and persistent COVID symptom), and hospitalization (hospitalized, in hospital, and home-isolated). The present meta-analysis was conducted according to The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 statement using R software 4.1.3 to create forest plots. Q statistics and the I ² index were used to evaluate heterogeneity in this meta-analysis.

Results

Six observational studies conducted in Spain, Austria, Switzerland, Canada, and the USA involving 419 hospitalized and 742 non-hospitalized COVID-19 survivors were included. The number of COVID-19 survivors in included studies ranged from 63 to 431, and follow-up data were collected through visits in four studies and another two used an electronic questionnaire, visit and telephone, respectively. Significant increase in the risks of long dyspnea (OR = 3.18, 95% CI = 1.90-5.32), anxiety (OR = 3.09, 95% CI = 1.47-6.47), myalgia (OR = 2.33, 95% CI = 1.02-5.33), and hair loss (OR = 2.76, 95% CI = 1.07-7.12) risk were found in hospitalized COVID-19 survivors compared with outpatients. Conversely, persisting ageusia risk was significantly reduced in hospitalized COVID-19 survivors than in non-hospitalized patients.

Conclusion

The findings suggested that special attention and patient-centered rehabilitation service based on a needs survey should be provided for hospitalized COVID-19 survivors who experienced high post-acute COVID-19 symptoms risk.

Psychological and Cognitive Effects of Long COVID: A Narrative Review Focusing on the Assessment and Rehabilitative Approach

Long COVID is a clinical syndrome characterized by profound fatigue, neurocognitive difficulties, muscle pain, weakness, and depression, lasting beyond the 3–12 weeks following infection with SARS-CoV-2. Among the symptoms, neurocognitive and psychiatric sequelae, including attention and memory alterations, as well as anxiety and depression symptoms, have become major targets of current healthcare providers given the significant public health impact. In this context, assessment tools play a crucial role in the early screening of cognitive alterations due to Long COVID. Among others, the general cognitive assessment tools, such as the Montreal Cognitive assessment, and more specific ones, including the State Trait Inventory of Cognitive Fatigue and the Digit Span, may be of help in investigating the main neurocognitive alterations. Moreover, appropriate neurorehabilitative programs using specific methods and techniques (conventional and/or advanced) through a multidisciplinary team are required to treat COVID-19-related cognitive and behavioral abnormalities. In this narrative review, we sought to describe the main neurocognitive and psychiatric symptoms as well as to provide some clinical advice for the assessment and treatment of Long COVID.

Global Trends and Research Hotspots in Long COVID: A Bibliometric Analysis

Long COVID is a condition distinguished by long-term sequelae that occur or persist after the convalescence period of COVID-19. During the COVID-19 pandemic, more and more people who tested positive for SARS-CoV-2 experienced long COVID, which attracted the attention of researchers. This study aims to assess the pattern of long COVID research literature, analyze the research topics, and provide insights on long COVID. In this study, we extracted 784 publications from Scopus in the field of long COVID. According to bibliometric analysis, it is found that: developed countries in Europe and America were in leading positions in terms of paper productivity and citations. The International Journal of Environmental Research and Public Health and the Journal of Clinical Medicine were leading journals in the perspective of publications count, and Nature Medicine had the highest number of citations. Author Greenhalgh T has the highest number of papers and citations. The main research topics were: pathophysiology, symptoms, treatment, and epidemiology. The causes of long COVID may be related to organ injury, inflammation, maladaptation of the angiotensin-converting enzyme 2 (ACE2) pathway, and mental factors. The symptoms are varied, including physical and psychological symptoms. Treatment options vary from person to person. Most patients developed at least one long-term symptom. Finally, we presented some possible research opportunities.

The "Elastic Perspective" of SARS-CoV-2 Infection and the Role of Intrinsic and Extrinsic Factors

Elastin represents the structural component of the extracellular matrix providing elastic recoil to tissues such as skin, blood vessels and lungs. Elastogenic cells secrete soluble tropoelastin monomers into the extracellular space where these monomers associate with other matrix proteins (e.g., microfibrils and glycoproteins) and are crosslinked by lysyl oxidase to form insoluble fibres. Once elastic fibres are formed, they are very stable, highly resistant to degradation and have an almost negligible turnover. However, there are circumstances, mainly related to inflammatory conditions, where increased proteolytic degradation of elastic fibres may lead to consequences of major clinical relevance. In severely affected COVID-19 patients, for instance, the massive recruitment and activation of neutrophils is responsible for the profuse release of elastases and other proteolytic enzymes which cause the irreversible degradation of elastic fibres. Within the lungs, destruction of the elastic network may lead to the permanent impairment of pulmonary function, thus suggesting that elastases can be a promising target to preserve the elastic component in COVID-19 patients. Moreover, intrinsic and extrinsic factors additionally contributing to damaging the elastic component and to increasing the spread and severity of SARS-CoV-2 infection are reviewed.