Post-covid medical complaints following infection with SARS-CoV-2 Omicron vs Delta variants

Post-COVID symptoms after SARS-CoV-2 omicron infection and the effect of booster vaccination: A population-based cohort study

BACKGROUND

The impact of vaccination on the type and risk of specific post-COVID symptoms after Omicron infection is not clear. We aimed to investigate the excess risk and patterns of 22 symptoms 3-5 months after Omicron infection, comparing uninfected and infected subjects with and without recent booster vaccination.

METHODS

We conducted a population-based prospective study based on four questionnaire-based cohorts linked to national health registries. Our study includes female and male participants aged 11-80 years from The Norwegian Mother, Father, and Child Cohort Study, The Norwegian Influenza Pregnancy Cohort, The Senior Cohort, and The Young Adult Cohort. All participants registered presence of 22 COVID-related symptoms irrespective of infection and vaccination status.

RESULTS

The study sample includes more than 31,000 uninfected and 26,000 Omicron infected subjects. Among infected subjects, 12 % were vaccinated with two doses >130 days before the primary infection (median 154 days) but had not received a third dose, while 76 % had received a third (booster) dose (median 40 days before infection). Among those with two doses only, the excess risk for new symptoms after infection (vs. no infection) were up to 15 % for women and 9 % for men. Among infected subjects with recent booster dose, the corresponding excess risks were 7 % among women and up to 5 % among men. The largest risk differences after recent booster vaccination were seen for poor memory, brain fog, and fatigue. Post-COVID symptoms were more often detected among young and middle-aged adults than among adolescents and older age groups.

CONCLUSION

Recent booster vaccination before infection substantially reduced both neurocognitive and cardiorespiratory symptoms occurring at least 3 months after Omicron infection.

Lupus and SARS-CoV-2: What have we learned after the pandemic?

After the end of the COVID-19 public health emergency, we analysed the relationship between Systemic Lupus Erythematosous (SLE) and COVID-19 from the virologist's perspective based on recent findings. SLE and COVID-19 co-morbidity present unique challenges, as individuals with SLE may be at increased risk for severe COVID-19 illness due to immune system abnormalities and ongoing therapies. Effective management of both diseases requires careful monitoring, adherence to vaccination programs, preventive measures and approved and patient-tailored therapies. This review covers various aspects, including the clinical outcome of SLE patients infected by SARS-CoV-2, the impact of this infection on SLE onset or flare-ups and the benefits of vaccination for this population. Furthermore, this review presents the most recent recommendations on clinical management of COVID-19 in rheumatic patients, including those with SLE, discussing the currently available therapeutic options. Finally, we explore the most effective tools for SARS-CoV-2 diagnosis in autoimmune conditions and examine prognostic biomarkers in COVID-19 rheumatic patients with potential implications on their clinical oversight. By adopting a comprehensive approach, we address these complexities from the virologist's perspective, aiming to improve health care for this vulnerable population.

Review of organ damage from COVID and Long COVID: a disease with a spectrum of pathology

Long COVID, as currently defined by the World Health Organization (WHO) and other authorities, is a symptomatic condition that has been shown to affect an estimated 10 %-30 % of non-hospitalized patients after one infection. However, COVID-19 can also cause organ damage in individuals without symptoms, who would not fall under the current definition of Long COVID. This organ damage, whether symptomatic or not, can lead to various health impacts such as heart attacks and strokes. Given these observations, it is necessary to either expand the definition of Long COVID to include organ damage or recognize COVID-19-induced organ damage as a distinct condition affecting many symptomatic and asymptomatic individuals after COVID-19 infections. It is important to consider that many known adverse health outcomes, including heart conditions and cancers, can be asymptomatic until harm thresholds are reached. Many more medical conditions can be identified by testing than those that are recognized through reported symptoms. It is therefore important to similarly recognize that while Long COVID symptoms are associated with organ damage, there are many individuals that have organ damage without displaying recognized symptoms and to include this harm in the characterization of COVID-19 and in the monitoring of individuals after COVID-19 infections.

Refinement of post-COVID condition core symptoms, subtypes, determinants, and health impacts: a cohort study integrating real-world data and patient-reported outcomes

BACKGROUND

Post-COVID-19 condition (PCC) affects millions of people, and is an essential component of the long-term impact of COVID-19 during the post-pandemic era. Yet, consensus on clinical case definition and core components of PCC remains lacking, affecting our ability to inform research and evidence-based management. Our study aims 1) to identify the most specific symptoms for PCC, and identify clinical subtypes; 2) to evaluate both virus- and host-related determinants of PCC, and 3) assess the impact of PCC on physical and mental health.

METHODS

We studied participants from UK Biobank who completed a health and wellbeing survey between June and September 2022. Participants reported the current conditions of the presence, duration, and functional limitations of 45 symptoms, using an online questionnaire designed specifically for COVID-19 research. SARS-CoV-2 infection status and disease history were obtained through linkage to surveillance data and electronic medical records, respectively. Participants reporting symptoms within 30 days after infection (acute phase) were excluded. The most specific PCC symptoms were defined using two criteria: statistical significance (P < 0.05 after Bonferroni correction) and clinical relevance (absolute risk increase > 5%). Propensity score weighting was used to control for confounding. Subtypes of PCC were then defined based on the specific symptoms among the COVID-19 infected individuals. A multivariable regression was used to study pathogen- and host-related risk factors for PCC, and its impact on 13 physical and 4 mental health patient-reported functional outcomes.

FINDINGS

172,303 participants (mean age 68.9, 57.4% female) were included in the analysis, of whom 43,395 had PCR-confirmed COVID-19. We identified 10 most specific symptoms and classified four PCC subtypes: ENT subtype (30.1%), characterized by alterations in smell, taste, and hearing loss; cardiopulmonary subtype (10.4%), characterized by shortness of breath, postural tachycardia, chest tightness, and chest pressure; neurological subtype (23.5%), characterized by brain fog and difficulty speaking; and general fatigue subtype (38.0%), characterized by mild fatigue. A higher PCC risk was observed for patients with Wild-type variant, multiple infections, and severe acute COVID-19 illness, consistently across the four PCC subtypes. In addition, a range of factors, including socioeconomic deprivation, higher BMI, unhealthy lifestyle, and multiple chronic health conditions, were associated with increased PCC risk, except for age and sex. Conversely, vaccination was associated with a largely reduced PCC risk, particularly for the cardiopulmonary subtypes. Individuals with PCC experienced a much worse physical and mental health. Specifically, the cardiopulmonary subtype had the most pronounced adverse impact on function impairments, followed by neurological, mild fatigue, and ENT subtype. The most affected functions included the ability to concentrate, participate in day-to-day work, and emotional vulnerability to health problems.

INTERPRETATION

PCC can be categorized into four distinct subtypes based on ten core symptoms. These subtypes appeared to share a majority of pathogen and host-related risk factors, but their impact on health varied markedly by subtype. Our findings could help refine current guidelines for precise PCC diagnosis and progression, enhance the identification of PCC subgroups for targeted research, and inform evidence-based policy making to tackle this new and debilitating condition.

FUNDING

NIHR Senior Research Fellowship (grant SRF-2018-11-ST2-004).

Persistence of Long COVID Symptoms Two Years After SARS-CoV-2 Infection: A Prospective Longitudinal Cohort Study

BACKGROUND/OBJECTIVES

Millions of individuals worldwide continue to experience symptoms following SARS-CoV-2 infection. This study aimed to assess the prevalence and phenotype of multi-system symptoms attributed to Long COVID-including fatigue, pain, cognitive-emotional disturbances, headache, cardiopulmonary issues, and alterations in taste and smell-that have persisted for at least two years after acute infection, which we define as "persistent Long COVID". Additionally, the study aimed to identify clinical features and blood biomarkers associated with persistent Long COVID symptoms.

METHODS

We sent a detailed long COVID symptoms questionnaire to an existing cohort of 1258 vaccinated adults (age 18-79 years) who had mild infection (e.g., non-hospitalized) SARS-CoV-2 Delta variant 2 years earlier. These individuals had comprehensive datasets, including blood samples, available for further analysis. We estimated prevalence of persistent long COVID two years post-infection using weighted adjustment (Horvitz-Thompson estimator) to overcome reporting bias. Multivariable logistic regression models were used to determine association of clinical features and blood biomarkers (pre-infection SARS-CoV-2 RBD-IgG, SARS-CoV-2 neutralizing antibodies, and pre-infection and post-infection neurofilament light) with prevalence of persistent long COVID.

RESULTS

N = 323 participants responded to the survey, of whom N = 74 (23%) reported at least one long COVID symptom that had persisted for two years after the acute infection. Weighted prevalence of persistent long COVID symptoms was 21.5% (95% CI = 16.7-26.3%). Female gender, smoking, and severity of acute COVID-19 infection were significantly associated with persistent Long COVID. The blood biomarkers assessed were not significantly associated with persistent Long COVID.

CONCLUSIONS

Among vaccinated adults two years after mild infection with Delta variant SARS-CoV-2, persistent symptoms attributed to Long COVID are extremely common, certain subgroups are at higher risk, and further research into biological mechanisms and potential treatment targets is needed.

Comparison of post-COVID-19 symptoms in patients infected with the SARS-CoV-2 variants delta and omicron-results of the Cross-Sectoral Platform of the German National Pandemic Cohort Network (NAPKON-SUEP)

PURPOSE

The influence of new SARS-CoV-2 variants on the post-COVID-19 condition (PCC) remains unanswered. Therefore, we examined the prevalence and predictors of PCC-related symptoms in patients infected with the SARS-CoV-2 variants delta or omicron.

METHODS

We compared prevalences and risk factors of acute and PCC-related symptoms three months after primary infection (3MFU) between delta- and omicron-infected patients from the Cross-Sectoral Platform of the German National Pandemic Cohort Network. Health-related quality of life (HrQoL) was determined by the EQ-5D-5L index score and trend groups were calculated to describe changes of HrQoL between different time points.

RESULTS

We considered 758 patients for our analysis (delta: n = 341; omicron: n = 417). Compared with omicron patients, delta patients had a similar prevalence of PCC at the 3MFU (p = 0.354), whereby fatigue occurred most frequently (n = 256, 34%). HrQoL was comparable between the groups with the lowest EQ-5D-5L index score (0.75, 95% CI 0.73-0.78) at disease onset. While most patients (69%, n = 348) never showed a declined HrQoL, it deteriorated substantially in 37 patients (7%) from the acute phase to the 3MFU of which 27 were infected with omicron.

CONCLUSION

With quality-controlled data from a multicenter cohort, we showed that PCC is an equally common challenge for patients infected with the SARS-CoV-2 variants delta and omicron at least for the German population. Developing the EQ-5D-5L index score trend groups showed that over two thirds of patients did not experience any restrictions in their HrQoL due to or after the SARS-CoV-2 infection at the 3MFU.

CLINICAL TRAIL REGISTRATION

The cohort is registered at ClinicalTrials.gov since February 24, 2021 (Identifier: NCT04768998).

SARS-CoV-2 propagation to the TPH2-positive neurons in the ventral tegmental area induces cell death via GSK3β-dependent accumulation of phosphorylated tau

COVID-19, an infectious disease caused by SARS-CoV-2, was declared a pandemic by the WHO in 2020. Psychiatric symptoms including sleep disturbance, memory impairment, and depression are associated with SARS-CoV-2 infection. These symptoms are causes long-term mental and physical distress in recovering patients; however, the underlying mechanism is unclear. In this study, we determined the effects of SARS-CoV-2 infection on brain tissue using k18hACE2 mice. Using brain tissue from 18hACE2 mice infected with SARS-CoV-2 through intranasal administration, SARS-CoV-2 spike protein and RNA were analyzed by immunohistochemical staining and in-situ hybridization. Immunohistochemical analysis revealed that Tryptophan hydroxylase 2 (TPH2)-positive cells and SARS-CoV-2 spike protein were co-localized in the ventral tegmental area of SARS-CoV-2-infected mice. We observed decreased TPH2 expression and increased accumulation of phosphorylated tau protein and Phospho-Histone H2A.X (γH2AX) expression in the ventral tegmental region. In addition, activation of glycogen synthase kinase 3β (GSK3β) was induced by SARS-CoV-2 infection. Overall, our results suggest that SARS-CoV-2 infection of TPH2-positive cells in the ventral tegmental area induces neuronal cell death through increased accumulation of phosphorylated tau. Attenuation of the GSK3β pathway and decreased serotonin synthesis through suppression of TPH2 expression may contribute to the development of neurological symptoms.

Characteristics and predictors of Long Covid in children: a 3-year prospective cohort study

Background

Children can develop Long Covid, however long term outcomes and their predictors are poorly described in these patients. The primary aim is to describe characteristics and predictors of Long Covid in children assessed in-clinics up to 36 months post-SARS-CoV-2 infection, as well as investigate the role of vaccines in preventing Long Covid, risk of reinfections and development of autoimmune diseases.

Methods

Children aged 0-18 years old with confirmed SARS-CoV-2 infection were invited for a prospective follow-up assessment at a peadiatric post-covid clinic in Rome, Italy, at serial intervals (3-, 6-, 12-, 18-, 24- and 36-months post-infection onset, between 01/02/2020 and 28/02/2024). Long Covid was defined as persistence of otherwise unexplained symptoms for at least three months after initial infection.

Findings

1319 patients were initially included, 1296 reached the 3 months follow-up or more. Of the patients who underwent multiple follow-ups, 23.2% (301), 169 (13.2%), 89 (7.9%), 67 (6.1%), 47 (7.1%) were diagnosed with Long Covid at 3-6-12-18-24 months, respectively For the primary outcome of Long Covid at three months, age >12 years (P < 0.001, OR 11.33, 95% CI 4.2; 15.15), comorbidities (P = 0.008, OR 1.83, 95% CI 1.06; 2.44), being infected with original variants (P < 0.001, OR 4.77, 95% CI 2.46; 14.47), female sex (P < 0.001, OR 1.62, 95% CI 1.02; 1.89) were statistically significant risk factors. Age >12 years (P = 0.002, OR 9.37, 95% CI 1.58; 8.64), and infection with original (P = 0.012, OR 3.52, 95% CI 1.32; 8.64) and alfa (P < 0.001, OR 4.09, 95% CI 2.01; 8.3) SARS-CoV-2 variants remained statistically significant risk factors for Long Covid duration for at least 18 months. Vaccination was associated with a lower risk of long covid at 3, 6 and 12 months for older children and a lower risk of reinfections. Being infected with the original SARS-CoV-2 variant was associated with a higher risk of new-onset autoimmune diseases ((P = 0.035, 95% CI 1.12; 2.4). One patient was diagnosed with Long Covid after a re-infection.

Interpretation

This is the longest follow-up study of children with SARS-CoV-2 infection, showing a significant and long-lasting burden of Long Covid in the pediatric population. Our findings highlight the urgent need of investing in pediatric Long Covid in order to find effective diagnostic and therapeutic approaches, as well can inform preventive strategies in case of future pandemics.

Funding

This study has been funde by Pfizer non-competitive grant, granted to DB (#65925795).

The Omicron Variant Is Associated with a Reduced Risk of the Post COVID-19 Condition and Its Main Phenotypes Compared to the Wild-Type Virus: Results from the EuCARE-POSTCOVID-19 Study

Post COVID-19 condition (PCC) is defined as ongoing symptoms at ≥1 month after acute COVID-19. We investigated the risk of PCC in an international cohort according to viral variants. We included 7699 hospitalized patients in six centers (January 2020-June 2023); a subset of participants with ≥1 visit over the year after clinical recovery were analyzed. Variants were observed or estimated using Global Data Science Initiative (GISAID) data. Because patients returning for a post COVID-19 visit may have a higher PCC risk, and because the variant could be associated with the probability of returning, we used weighted logistic regressions. We estimated the proportion of the effect of wild-type (WT) virus vs. Omicron on PCC, which was mediated by Intensive Care Unit (ICU) admission, through a mediation analysis. In total, 1317 patients returned for a post COVID visit at a median of 2.6 (IQR 1.84-3.97) months after clinical recovery. WT was present in 69.6% of participants, followed by the Alpha (14.4%), Delta (8.9%), Gamma (3.9%) and Omicron strains (3.3%). Among patients with PCC, the most common manifestations were fatigue (51.7%), brain fog (32.7%) and respiratory symptoms (37.2%). Omicron vs. WT was associated with a reduced risk of PCC and PCC clusters; conversely, we observed a higher risk with the Delta and Alpha variants vs. WT. In total, 42% of the WT effect vs. Omicron on PCC risk appeared to be mediated by ICU admission. A reduced PCC risk was observed after Omicron infection, suggesting a possible reduction in the PCC burden over time. A non-negligible proportion of the variant effect on PCC risk seems mediated by increased disease severity during the acute disease.

Exploring cognitive impairments and the efficacy of phosphatidylcholine and computer-assisted cognitive training in post-acute COVID-19 and post-acute COVID-19 Vaccination Syndrome

Purpose

The COVID-19 pandemic has led to millions of confirmed cases worldwide, resulting in numerous deaths and hospitalizations. Long-term symptoms after infection or vaccination, known as Post-acute COVID-19 Syndrome (PACS) or Post-acute COVID-19 Vaccination Syndrome (PACVS), present a challenge for the healthcare system. Among the various neurological symptoms, cognitive impairments are frequently observed in PACS/PACVS patients. This study aimed to understand cognitive deficits in PACS/PACVS patients and evaluated potential treatment options, including phosphatidylcholine and computer-assisted cognitive training (CCT).

Methods

The Neuro-COVID Outpatient Clinic at Evangelic Hospital Vienna evaluated n = 29 PACS/PACVS patients from May 2023 to October 2023. Enrolled patients were divided into three therapy schemes: Group A received phosphatidylcholine, B received phosphatidylcholine plus access to a computer-assisted cognitive training program, and C (divided into two subgroups) served as a control group. Cognitive impairments were evaluated in multiple assessments (initial and during therapy) using the COGBAT test. Simultaneously, an assessment of the quality of life was conducted using the WHOQOL-BREF.

Results

Primary cognitive impairments, especially attentional deficits were notably evident compared to the general population. While all treatment groups showed cognitive improvement (significant or with a positive trend, but without reaching the level of statistical significance) after therapy, no significant interaction was found between assessment time points and treatment schemes for overall cognitive performance, attention, memory, and executive functions, suggesting consistency across the groups. The WHOQOL-BREF primarily demonstrated deficits in the domains of physical health and psychological well-being.

Conclusion

This study examined the impact of PACS/PACVS on cognitive performance and evaluated phosphatidylcholine and CCT as potential treatment options. Patients with PACS/PACVS showed notable cognitive deficits, especially in the domain attention. While the effectiveness of phosphatidylcholine and CCT in treating cognitive deficits was inconclusive, the study indicated the possibility of spontaneous remission of cognitive deficits in PACS/PACVS.

Impact of Long SARS-CoV-2 Omicron Infection on the Health Care Burden: Comparative Case-Control Study Between Omicron and Pre-Omicron Waves

BACKGROUND

Following the initial acute phase of COVID-19, health care resource use has escalated among individuals with SARS-CoV-2 infection.

OBJECTIVE

This study aimed to compare new diagnoses of long COVID and the demand for health services in the general population after the Omicron wave with those observed during the pre-Omicron waves, using similar assessment protocols for both periods and to analyze the influence of vaccination.

METHODS

This matched retrospective case-control study included patients of both sexes diagnosed with acute SARS-CoV-2 infection using reverse transcription polymerase chain reaction or antigen tests in the hospital microbiology laboratory during the pandemic period regardless of whether the patients were hospitalized. We included patients of all ages from 2 health care departments that cover 604,000 subjects. The population was stratified into 2 groups, youths (<18 years) and adults (≥18 years). Patients were followed-up for 6 months after SARS-CoV-2 infection. Previous vaccination, new diagnoses, and the use of health care resources were recorded. Patients were compared with controls selected using a prospective score matched for age, sex, and the Charlson index.

RESULTS

A total of 41,577 patients with a history of prior COVID-19 infection were included, alongside an equivalent number of controls. This cohort encompassed 33,249 (80%) adults aged ≥18 years and 8328 (20%) youths aged <18 years. Our analysis identified 40 new diagnoses during the observation period. The incidence rate per 100 patients over a 6-month period was 27.2 for vaccinated and 25.1 for unvaccinated adults (P=.09), while among youths, the corresponding rates were 25.7 for vaccinated and 36.7 for unvaccinated individuals (P<.001). Overall, the incidence of new diagnoses was notably higher in patients compared to matched controls. Additionally, vaccinated patients exhibited a reduced incidence of new diagnoses, particularly among women (P<.001) and younger patients (P<.001) irrespective of the number of vaccine doses administered and the duration since the last dose. Furthermore, an increase in the use of health care resources was observed in both adult and youth groups, albeit with lower figures noted in vaccinated individuals. In the comparative analysis between the pre-Omicron and Omicron waves, the incidence of new diagnoses was higher in the former; however, distinct patterns of diagnosis were evident. Specifically, depressed mood (P=.03), anosmia (P=.003), hair loss (P<.001), dyspnea (<0.001), chest pain (P=.04), dysmenorrhea (P<.001), myalgia (P=.011), weakness (P<.001), and tachycardia (P=.015) were more common in the pre-Omicron period. Similarly, health care resource use, encompassing primary care, specialist, and emergency services, was more pronounced in the pre-Omicron wave.

CONCLUSIONS

The rise in new diagnoses following SARS-CoV-2 infection warrants attention due to its potential implications for health systems, which may necessitate the allocation of supplementary resources. The absence of vaccination protection presents a challenge to the health care system.

Risk of COVID-19 in Children throughout the Pandemic and the Role of Vaccination: A Narrative Review

At the beginning of the coronavirus disease 2019 (COVID-19) pandemic, persons ≥65 years of age and healthcare personnel represented the most vulnerable groups with respect to risk of infection, severe illness, and death. However, as the pandemic progressed, there was an increasingly detrimental effect on young children and adolescents. Severe disease and hospitalization increased over time in pediatric populations, and containment measures created substantial psychosocial, educational, and economic challenges for young people. Vaccination of children against COVID-19 has been shown to reduce severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections and severe outcomes in pediatric populations and may also help to prevent the spread of variants of concern and improve community immunity. This review discusses the burden of COVID-19 on children throughout the pandemic, the role of children in disease transmission, and the impact of COVID-19 vaccination.

Symptoms, Course, and Factors Related to Long-Term Morbidity, Including Differences between Infection Strains, in Patients with Long COVID in a Primary Care Clinic in Japan: An Observational Study

Objectives: The objectives were to investigate the clinical characteristics and course of long COVID, defined as the persistence of symptoms at least one month after the onset of COVID-19, in outpatients and to clarify differences in symptoms between SARS CoV-2 mutant strains. Methods: Our observational study in a primary care institution in Japan included 1053 patients with long COVID who visited our outpatient clinic between April 2021 and March 2023. Symptom distribution, performance status, and patient background at the time of the first outpatient visit were compared between infectious strains (Delta and before group and Omicron group). Background factors and symptoms related to time to remission were also analyzed. Results: The severity of COVID-19 in the acute phase was mild, moderate, and severe in 82.2%, 14.9%, and 2.9% in the Delta and before group; and in 97.6%, 1.7%, and 0.4% in the Omicron group, respectively. Vaccination coverage was significantly different between the Delta and before (37.1%) and Omicron groups (73.1%) (p < 0.001), probably due to the period of vaccine unavailability in the former group. Symptoms of fatigue and headache occurred most frequently, irrespective of infectious strain. The mean number of symptoms per patient was significantly higher in the Delta and before group than the Omicron group (3.4 vs. 2.7, p < 0.0001). The median time overall to remission of long COVID was 169 days. Cox hazard model analysis identified female sex, high body mass index, and dyspnea (but not infectious strain) as significant factors prolonging the time to remission (p < 0.05). Conclusions: Differences in the number of symptoms between infectious strains may be related to differences in viral virulence and/or vaccination coverage. However, the clinical course was found to be minimally influenced by the infectious strain. The present results should improve the understanding of prognosis in patients with long COVID from both the clinical and social perspectives.

Comparative SARS-CoV-2 Omicron BA.5 variant and D614G-Wuhan strain infections in ferrets: insights into attenuation and disease progression during subclinical to mild COVID-19

Introduction

As the SARS-CoV-2 virus continues to evolve and new variants emerge, it becomes crucial to understand the comparative pathological and immunological responses elicited by different strains. This study focuses on the original Wuhan strain and the Omicron variant, which have demonstrated significant differences in clinical outcomes and immune responses.

Methods

We employed ferrets as an experimental model to assess the D614G variant (a derivative of the Wuhan strain) and the Omicron BA.5 variant. Each variant was inoculated into separate groups of ferrets to compare disease severity, viral dissemination, and immune responses.

Results

The D614G variant induced more severe disease and greater viral spread than the Omicron variant. Notably, ferrets infected with the D614G variant exhibited a robust neutralizing antibody response, whereas those infected with the Omicron variant failed to produce a detectable neutralizing antibody response. Despite the clearance of the virus from nearly all tissues by 7 days post-infection, an increase in pathological lesions was observed from 14 to 21 days, particularly in those infected with the D614G variant, suggesting a sustained immune response even after viral clearance.

Discussion

These findings underscore the adaptability of SARS-CoV-2 and illuminate how susceptibility and clinical manifestations vary across different strains and species. The results emphasize the necessity of considering both the direct effects of viral infection and the indirect, often prolonged, impacts of the immune response in evaluating the outcomes of SARS-CoV-2 infections.

Protracted exercise tolerance post-coronavirus disease 2019 in endurance athletes: A survey

Background

The global coronavirus disease 2019 (COVID-19) pandemic irrevocably influenced our lives, yet research in a diversity of countries is lacking. Cardiorespiratory fitness may be impaired for up to a year post-COVID-19 infection.

Objectives

Our study aimed to compare acute and exertional symptoms, fatigue, and exercise performance in masters-age endurance athletes according to their return-to-sport status.

Method

A cross-sectional survey-based observational study of long-distance runners and cyclists was conducted. Data were stratified into two groups: those who returned to their pre-illness level of sport and those who did not and were compared statistically.

Results

A total of 308 survey responses were included in the analysis. The mean age of the athletes was 44.9 + 10.2 years, with 55.2% being male. The group that did not return to their pre-illness level of sport (31.5%) had more post-COVID sequelae, worse illness severity, with a higher frequency of resting and exertional symptoms, notably fatigue and dyspnoea. Decreased exercise capacity was correlated with increased physical fatigue scores.

Conclusion

Almost one-third of endurance athletes suffered protracted exercise tolerance post-COVID-19. Long-term symptoms may be more consequential in this athlete population.

Clinical Implications

Symptoms that may indicate cardiopulmonary consequences in recreational athletes should be investigated in order to facilitate return to sport and the important mental and physical benefits thereof. This will augment outcomes after respiratory tract infections and management of return to sport and expectations of endurance athletes.

Nirmatrelvir/ritonavir treatment and the risk of post-COVID condition over 180 days in Malaysia

BACKGROUND

The effect of nirmatrelvir/ritonavir on preventing post-COVID condition (PCC) in the BA4, BA5, and XBB Omicron predominant periods is not well understood. The purpose of this study was to assess how nirmatrelvir/ritonavir treatment affected both PCC and health-related quality of life.

METHODS

This retrospective cohort study enrolled 2,524 adults aged 18 years and older who were eligible for nirmatrelvir/ritonavir between July 14 to November 14, 2022. All outcomes were observed from the patient's first visit to the primary health clinic, 1 week, 1 month, 3 months, and 6 months after testing positive for COVID-19. The primary outcome was the presence of PCC. Secondary outcomes included the effects on health-related quality of life, such as walking, bathing and dressing, activities, cause adverse emotions or signs that prevent individuals from leading normal lives over a 180-day observation period.

RESULTS

There were no significant differences observed between the nirmatrelvir/ritonavir and those not administered (control group) in terms of PCC symptoms at 3 months (OR 0.71 95% CI 0.31, 1.64) and 6 months (OR 1.30 95% CI 0.76, 2.21). At 3 months, the use of nirmatrelvir/ritonavir was associated with a 26% reduction in symptoms causing negative emotions (OR 0.74 95% CI 0.60, 0.92) and an increased likelihood of symptoms limiting walking (OR 1.58 95% CI 1.10, 2.27). However, there were no significant differences between the nirmatrelvir/ritonavir and the control group in terms of the impact of PCC on health-related quality of life at 6 months.

CONCLUSIONS

Our study indicates that the administration of nirmatrelvir/ritonavir does not significantly reduce PCC after 3 months and 6 months in a population with high vaccination coverage.

Using the ClinFIT COVID-19 Instrument to Assess the Functional Impairments Specific to Post-COVID-19 Patients in Romania

INTRODUCTION

The COVID-19 pandemic has led to approximately 3.5 million cases in Romania, causing systemic inflammation and over 200 symptoms affecting various body systems. This complexity has challenged rehabilitation systems, necessitating personalized plans tailored to each patient's illness stage and impairment level. The ISPRM-developed ClinFIT COVID-19 instrument, aligned with the ICF categories, assists in assessing patients during acute, post-acute, and long-term phases.

OBJECTIVE

This study aimed to evaluate and assess functional impairments in post-COVID-19 patients in Romania, with a secondary goal of generating rehabilitation directions.

METHODS

Data were collected from patients at two Bucharest medical centers, including those with persistent symptoms post-acute phase. Participants were assessed using the adapted ClinFIT COVID-19 instrument, and descriptive statistics were applied.

CONCLUSIONS

Findings revealed diverse functional impairments in physical, psychological, and social domains among post-COVID-19 patients, with severe impairments more common in those with long-term COVID-19. Complete impairment in complex movement and paid work was noted, affecting one-third of salaried employees and forcing some to retire. In the acute phase, the most frequent functional impairments were sleep, attention, pain sensation, and exercise tolerance functions. In contrast, the most severely affected functions were exercise tolerance and mobility joint functions. Age did not positively correlate with any of the analyzed functions. In the post-acute phase, sleep, energy, and drive functions remained the most frequently affected functions, while the most severely affected was, by far, the moving around function. In the post-acute period, respiratory and respiratory muscle functions strongly correlated with all tasks related to physical activity. In the long COVID-19 phase, remunerative employment was the most severely affected function, while attention functions remained the most frequently affected, similar to the acute phase. The ClinFIT COVID-19 instrument effectively captured these impairments, underscoring the need for comprehensive rehabilitation strategies.

SARS-CoV-2 envelope protein regulates innate immune tolerance

Severe COVID-19 often leads to secondary infections and sepsis that contribute to long hospital stays and mortality. However, our understanding of the precise immune mechanisms driving severe complications after SARS-CoV-2 infection remains incompletely understood. Here, we provide evidence that the SARS-CoV-2 envelope (E) protein initiates innate immune inflammation, via toll-like receptor 2 signaling, and establishes a sustained state of innate immune tolerance following initial activation. Monocytes in this tolerant state exhibit reduced responsiveness to secondary stimuli, releasing lower levels of cytokines and chemokines. Mice exposed to E protein before secondary lipopolysaccharide challenge show diminished pro-inflammatory cytokine expression in the lung, indicating that E protein drives this tolerant state in vivo. These findings highlight the potential of the SARS-CoV-2 E protein to induce innate immune tolerance, contributing to long-term immune dysfunction that could lead to susceptibility to subsequent infections, and uncovers therapeutic targets aimed at restoring immune function following SARS-CoV-2 infection.

Persistent immune abnormalities discriminate post-COVID syndrome from convalescence

BACKGROUND

Innate lymphoid cells (ILCs) are key organizers of tissue immune responses and regulate tissue development, repair, and pathology. Persistent clinical sequelae beyond 12 weeks following acute COVID-19 disease, named post-COVID syndrome (PCS), are increasingly recognized in convalescent individuals. ILCs have been associated with the severity of COVID-19 symptoms but their role in the development of PCS remains poorly defined.

METHODS AND RESULTS

Here, we used multiparametric immune phenotyping, finding expanded circulating ILC precursors (ILCPs) and concurrent decreased group 2 innate lymphoid cells (ILC2s) in PCS patients compared to well-matched convalescent control groups at > 3 months after infection or healthy controls. Patients with PCS showed elevated expression of chemokines and cytokines associated with trafficking of immune cells (CCL19/MIP-3b, FLT3-ligand), endothelial inflammation and repair (CXCL1, EGF, RANTES, IL-1RA, PDGF-AA).

CONCLUSION

These results define immunological parameters associated with PCS and might help find biomarkers and disease-relevant therapeutic strategies.

Specific sequelae symptoms of COVID-19 of Omicron variant in comparison with non-COVID-19 patients: a retrospective cohort study in Japan

Background

The specific long-term sequela of coronavirus disease 2019 (COVID-19), also known as long COVID of the Omicron variant remain unclear, due to a lack of cohort studies that include non-COVID patients with cold-like symptoms. The study was conducted to examine specific sequelae symptoms after severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection, which is considered the Omicron variant, compared with patients who were never-infected.

Methods

In this retrospective cohort study, we sent questionnaires in November 2022, targeting those who visited our fever outpatient unit of a single institution from July to September 2022. SARS-CoV-2 infection status was determined by SARS-CoV-2 polymerase chain reaction (PCR) test results during the study period collected in electronic medical records. Clinical characteristics at 30 days or more since the date of SARS-CoV-2 PCR test were assessed by the questionnaires. Multiple logistic regression was performed to investigate the independent association between SARS-CoV-2 infection and possible sequelae symptoms.

Results

In total, valid responses were received from 4,779 patients (mean age: 41.4 years, standard deviation: 19.8 years old). Among them, 3,326 (69.6%) and 1,453 (30.4%) were SARS-CoV-2 PCR test positive and never-infected, respectively. We found that patients with SARS-CoV-2 infection were more likely to have a loss of taste or smell [odds ratio (OR) 4.55, 95% confidence interval (CI): 1.93, 10.71], hair loss (OR 3.19, 95% CI: 1.67, 6.09), neurocognitive symptoms (OR 1.95, 95% CI: 1.43, 2.65), and respiratory symptoms (OR 1.23, 95% CI: 1.03, 1.47) than never-infected patients. SARS-CoV-2 infection was not associated with common cold symptoms, chronic physical distress, or diarrhea as sequelae symptoms. Further, SARS-CoV-2 vaccination showed protective effects on sequelae of loss of taste or smell and hair loss.

Conclusions

Loss of taste or smell, hair loss, neurocognitive symptoms, and respiratory symptoms were found to be specific sequelae of the SARS-CoV-2 Omicron variant. It is important not to miss these symptoms that follow SARS-CoV-2 infection and to recognize and manage the long COVID.

Post-COVID conditions following COVID-19 vaccination: a retrospective matched cohort study of patients with SARS-CoV-2 infection

COVID-19 vaccinations protect against severe illness and death, but associations with post-COVID conditions (PCC) are less clear. We aimed to evaluate the association between prior COVID-19 vaccination and new-onset PCC among individuals with SARS-CoV-2 infection across eight large healthcare systems in the United States. This retrospective matched cohort study used electronic health records (EHR) from patients with SARS-CoV-2 positive tests during March 2021-February 2022. Vaccinated and unvaccinated COVID-19 cases were matched on location, test date, severity of acute infection, age, and sex. Vaccination status was ascertained using EHR and integrated data on externally administered vaccines. Adjusted relative risks (RRs) were obtained from Poisson regression. PCC was defined as a new diagnosis in one of 13 PCC categories 30 days to 6 months following a positive SARS-CoV-2 test. The study included 161,531 vaccinated COVID-19 cases and 161,531 matched unvaccinated cases. Compared to unvaccinated cases, vaccinated cases had a similar or lower risk of all PCC categories except mental health disorders (RR: 1.06, 95% CI: 1.02-1.10). Vaccination was associated with ≥10% lower risk of sensory (RR: 0.90, 0.86-0.95), circulatory (RR: 0.88, 0.83-0.94), blood and hematologic (RR: 0.79, 0.71-0.89), skin and subcutaneous (RR: 0.69, 0.66-0.72), and non-specific COVID-19 related disorders (RR: 0.53, 0.51-0.56). In general, associations were stronger at younger ages but mostly persisted regardless of SARS-CoV-2 variant period, receipt of ≥3 vs. 1-2 vaccine doses, or time since vaccination. Pre-infection vaccination was associated with reduced risk of several PCC outcomes and hence may decrease the long-term consequences of COVID-19.

Prevalence and risk factors for long COVID among adults in Scotland using electronic health records: a national, retrospective, observational cohort study

Background

Long COVID is a debilitating multisystem condition. The objective of this study was to estimate the prevalence of long COVID in the adult population of Scotland, and to identify risk factors associated with its development.

Methods

In this national, retrospective, observational cohort study, we analysed electronic health records (EHRs) for all adults (≥18 years) registered with a general medical practice and resident in Scotland between March 1, 2020, and October 26, 2022 (98-99% of the population). We linked data from primary care, secondary care, laboratory testing and prescribing. Four outcome measures were used to identify long COVID: clinical codes, free text in primary care records, free text on sick notes, and a novel operational definition. The operational definition was developed using Poisson regression to identify clinical encounters indicative of long COVID from a sample of negative and positive COVID-19 cases matched on time-varying propensity to test positive for SARS-CoV-2. Possible risk factors for long COVID were identified by stratifying descriptive statistics by long COVID status.

Findings

Of 4,676,390 participants, 81,219 (1.7%) were identified as having long COVID. Clinical codes identified the fewest cases (n = 1,092, 0.02%), followed by free text (n = 8,368, 0.2%), sick notes (n = 14,469, 0.3%), and the operational definition (n = 64,193, 1.4%). There was limited overlap in cases identified by the measures; however, temporal trends and patient characteristics were consistent across measures. Compared with the general population, a higher proportion of people with long COVID were female (65.1% versus 50.4%), aged 38-67 (63.7% versus 48.9%), overweight or obese (45.7% versus 29.4%), had one or more comorbidities (52.7% versus 36.0%), were immunosuppressed (6.9% versus 3.2%), shielding (7.9% versus 3.4%), or hospitalised within 28 days of testing positive (8.8% versus 3.3%%), and had tested positive before Omicron became the dominant variant (44.9% versus 35.9%). The operational definition identified long COVID cases with combinations of clinical encounters (from four symptoms, six investigation types, and seven management strategies) recorded in EHRs within 4-26 weeks of a positive SARS-CoV-2 test. These combinations were significantly (p < 0.0001) more prevalent in positive COVID-19 patients than in matched negative controls. In a case-crossover analysis, 16.4% of those identified by the operational definition had similar healthcare patterns recorded before testing positive.

Interpretation

The prevalence of long COVID presenting in general practice was estimated to be 0.02-1.7%, depending on the measure used. Due to challenges in diagnosing long COVID and inconsistent recording of information in EHRs, the true prevalence of long COVID is likely to be higher. The operational definition provided a novel approach but relied on a restricted set of symptoms and may misclassify individuals with pre-existing health conditions. Further research is needed to refine and validate this approach.

Funding

Chief Scientist Office (Scotland), Medical Research Council, and BREATHE.

PASC (Post Acute Sequelae of COVID-19) is associated with decreased neutralizing antibody titers in both biological sexes and increased ANG-2 and GM-CSF in females

Post-acute sequelae of COVID-19 (PASC) or the continuation of COVID-19 (Coronavirus disease 2019) symptoms past 12 weeks may affect as many as 30% of people recovering from a SARS-CoV-2 (severe acute respiratory coronavirus 2) infection. The mechanisms regulating the development of PASC are currently not known; however, hypotheses include virus reservoirs, pre-existing conditions, microblood clots, immune dysregulation, as well as poor antibody responses. Importantly, virus neutralizing antibodies are essential for COVID-19 recovery and protection from reinfection but there is currently limited information on these immune regulators and associated cytokines in PASC patients. Understanding the key drivers of general and specific symptoms associated with Long COVID and the presence of virus neutralizing antibodies in PASC will aid in the development of therapeutics, diagnostics, and vaccines which currently do not exist. We designed a cross-sectional study to investigate systemic antibody and cytokine responses during COVID-19 recovery and PASC. In total, 195 participants were recruited in one of four groups: (1) Those who never had COVID-19 (No COVID); (2) Those in acute COVID-19 recovery (Acute Recovery) (4-12 weeks post infection); (3) Those who recovered from COVID-19 (Recovered) (+ 12 weeks from infection); and (4) those who had PASC (PASC) (+ 12 weeks from infection). Participants completed a questionnaire on health history, sex, gender, demographics, experiences with COVID-19 acute and COVID-19 recovery/continuing symptoms. Serum samples collected were evaluated for antibody binding to viral proteins, virus neutralizing antibody titers, and serum cytokine levels using Ella SimplePlex Immunoassay™ panels. We found participants with PASC reported more pre-existing conditions (e.g. such as hypertension, asthma, and obesity), and PASC symptoms (e.g. fatigue, brain fog, headaches, and shortness of breath) following COVID-19 than COVID-19 Recovered individuals. Importantly, we found PASC individuals to have significantly decreased levels of neutralizing antibodies toward both SARS-CoV-2 and the Omicron BA.1 variant. Sex analysis indicated that female PASC study participants had sustained antibody levels as well as levels of the inflammatory cytokines GM-CSF and ANG-2 over time following COVID-19. Our study reports people experiencing PASC had lower levels of virus neutralizing antibodies; however, the results are limited by the collection time post-COVID-19 and post-vaccination. Moreover, we found females experiencing PASC had sustained levels of GM-CSF and ANG-2. With lower levels of virus neutralizing antibodies, this data suggests that PASC individuals not only have had a suboptimal antibody response during acute SARS-CoV-2 infection but may also have increased susceptibility to subsequent infections which may exacerbate or prolong current PASC illnesses. We also provide evidence suggesting GM-CSF and ANG-2 to play a role in the sex-bias of PASC. Taken together, our findings maybe important for understanding immune molecular drivers of PASC and PASC subgroups.

Symptom trajectories of post-COVID sequelae in patients with acute Delta or Omicron infection in Bergen, Norway

Introduction

A substantial proportion of the over 700 million COVID-19 cases world-wide experience long-term symptoms. The objectives of this study were to compare symptom trajectories and risk factors for post-COVID-19 condition after Delta and Omicron infection.

Methods

This study consecutively recruited patients with SARS-CoV-2 infection from November 2021 to March 2022. We recorded demographics, comorbidities, vaccination status, sick leave, and 18 symptoms during acute infection and after 4 months. The primary outcome measures were symptoms during acute infection and after 4 months. Secondary outcome measures were work and school absenteeism.

Results

We followed a cohort of 1,374 non-hospitalized COVID-19 patients in Bergen, Norway, at three time points. The median age was 39.8 years and 11% were children <16 years. Common acute upper respiratory symptoms waned during follow-up. Fatigue remained common from acute infection (40%) until after 4 months (37%). Four months post-infection, patients reported increased frequencies of dyspnea (from 15% during acute illness to 25% at 4 months, p < 0.001), cognitive symptoms (from 9 to 32%, p < 0.001) and depression (from 1 to 17%, p < 0.001). Patients infected with Omicron reported less dyspnea (22% versus 27%, p = 0.046) and smell/taste problems (5% versus 19%, p < 0.001) at 4 months follow-up than those with Delta infection. Comorbidities and female sex were risk factors for persistent dyspnea and cognitive symptoms. Ten percent reported sick leave after acute illness, and vaccination reduced the risk of absenteeism (adjusted risk ratio: 0.36, 95% confidence interval: 0.15, 0.72, p = 0.008).

Conclusion

At 4 months, home-isolated patients infected with Omicron reported overall comparable symptom burden, but less dyspnea and smell/taste problems than Delta infected patients. Several acute symptoms waned during follow-up. It is worrying that dyspnea, neurocognitive symptoms, and particularly depression, increased significantly during the first 4 months after acute infection. Previous vaccination was protective against prolonged sick leave.

Impact of COVID-19 on risks and deaths of non-communicable diseases in the Western Pacific region

Countries and areas in the Western Pacific region (WPR) experienced the COVID-19 pandemic and took various preventive measures, which affected non-communicable diseases (NCDs) risks and mortality. Due to differences in COVID-19 prevention measures and other characteristics such as culture, religions, political systems, socioeconomic development, lifestyles, and health care systems, the effects of COVID-19 on NCDs varied greatly among WPR countries. Most countries had an increased all-cause and NCDs mortality during the pandemic, but some developed countries, including New Zealand, Singapore and Australia reported decreased mortality. The pandemic and the preventive measures increased NCD risk factors including unhealthy diet, lack of physical activity and sleep disorders. The effects varied by socioeconomic status and health conditions. COVID-19 related stress, food shortages, and confined lifestyle had immediate detrimental effects on NCDs, and also affected pregnancy outcomes with long-term effects on NCDs risks in coming years.

Damage to endothelial barriers and its contribution to long COVID

The world continues to contend with COVID-19, fueled by the emergence of viral variants. At the same time, a subset of convalescent individuals continues to experience persistent and prolonged sequelae, known as long COVID. Clinical, autopsy, animal and in vitro studies all reveal endothelial injury in acute COVID-19 and convalescent patients. Endothelial dysfunction is now recognized as a central factor in COVID-19 progression and long COVID development. Different organs contain different types of endothelia, each with specific features, forming different endothelial barriers and executing different physiological functions. Endothelial injury results in contraction of cell margins (increased permeability), shedding of glycocalyx, extension of phosphatidylserine-rich filopods, and barrier damage. During acute SARS-CoV-2 infection, damaged endothelial cells promote diffuse microthrombi and destroy the endothelial (including blood-air, blood-brain, glomerular filtration and intestinal-blood) barriers, leading to multiple organ dysfunction. During the convalescence period, a subset of patients is unable to fully recover due to persistent endothelial dysfunction, contributing to long COVID. There is still an important knowledge gap between endothelial barrier damage in different organs and COVID-19 sequelae. In this article, we mainly focus on these endothelial barriers and their contribution to long COVID.

Post-COVID-19 Condition After SARS-CoV-2 Infections During the Omicron Surge vs the Delta, Alpha, and Wild Type Periods in Stockholm, Sweden

Little is known about the post-COVID-19 condition (PCC) after infections with different SARS-CoV-2 variants. We investigated the risk of PCC diagnosis after primary omicron infections as compared with preceding variants in population-based cohorts in Stockholm, Sweden. When compared with omicron (n = 215 279, 0.2% receiving a PCC diagnosis), the adjusted hazard ratio (95% CI) was 3.26 (2.80-3.80) for delta (n = 52 182, 0.5% PCC diagnosis), 5.33 (4.73-5.99) for alpha (n = 97 978, 1.0% PCC diagnosis), and 6.31 (5.64-7.06) for the wild type (n = 107 920, 1.3% PCC diagnosis). These findings were consistent across all subgroup analyses except among those treated in the intensive care unit.

The determinants of COVID-induced brain dysfunctions after SARS-CoV-2 infection in hospitalized patients

The severity of the pandemic and its consequences on health and social care systems were quite diverse and devastating. COVID-19 was associated with an increased risk of neurological and neuropsychiatric disorders after SARS-CoV-2 infection. We did a cross-sectional study of 3 months post-COVID consequences of 178 Cuban subjects. Our study has a unique CUBAN COVID-19 cohort of hospitalized COVID-19 patients and healthy subjects. We constructed a latent variable for pre-health conditions (PHC) through Item Response Theory (IRT) and for post-COVID neuropsychiatric symptoms (Post-COVID-NPS) through Factor Analysis (FA). There seems to be a potential causal relationship between determinants of CIBD and post-COVID-NPS in hospitalized COVID-19 patients. The causal relationships accessed by Structural Equation Modeling (SEM) revealed that PHC (p < 0.001) and pre-COVID cognitive impairments (p < 0.001) affect the severity of COVID-19 patients. The severity of COVID-19 eventually results in enhanced post-COVID-NPS (p < 0.001), even after adjusting for confounders (age, sex, and pre-COVID-NPS). The highest loadings in PHC were for cardiovascular diseases, immunological disorders, high blood pressure, and diabetes. On the other hand, sex (p < 0.001) and pre-COVID-NPS including neuroticism (p < 0.001), psychosis (p = 0.005), cognition (p = 0.036), and addiction (p < 0.001) were significantly associated with post-COVID-NPS. The most common neuropsychiatric symptom with the highest loadings includes pain, fatigue syndrome, autonomic dysfunctionalities, cardiovascular disorders, and neurological symptoms. Compared to healthy people, COVID-19 patients with pre-health comorbidities or pre-neuropsychiatric conditions will have a high risk of getting severe COVID-19 and long-term post-COVID neuropsychiatric consequences. Our study provides substantial evidence to highlight the need for a complete neuropsychiatric follow-up on COVID-19 patients (with severe illness) and survivors (asymptomatic patients who recovered).

The neurobiology of SARS-CoV-2 infection

Worldwide, over 694 million people have been infected with SARS-CoV-2, with an estimated 55-60% of those infected developing COVID-19. Since the beginning of the pandemic in December 2019, different variants of concern have appeared and continue to occur. With the emergence of different variants, an increasing rate of vaccination and previous infections, the acute neurological symptomatology of COVID-19 changed. Moreover, 10-45% of individuals with a history of SARS-CoV-2 infection experience symptoms even 3 months after disease onset, a condition that has been defined as 'post-COVID-19' by the World Health Organization and that occurs independently of the virus variant. The pathomechanisms of COVID-19-related neurological complaints have become clearer during the past 3 years. To date, there is no overt - that is, truly convincing - evidence for SARS-CoV-2 particles in the brain. In this Review, we put special emphasis on discussing the  methodological difficulties of viral detection in CNS tissue and discuss immune-based (systemic and central) effects contributing to COVID-19-related CNS affection. We sequentially review the reported changes to CNS cells in COVID-19, starting with the blood-brain barrier and blood-cerebrospinal fluid barrier - as systemic factors from the periphery appear to primarily influence barriers and conduits - before we describe changes in brain parenchymal cells, including microglia, astrocytes, neurons and oligodendrocytes as well as cerebral lymphocytes. These findings are critical to understanding CNS affection in acute COVID-19 and post-COVID-19 in order to translate these findings into treatment options, which are still very limited.

Vascular "Long COVID": A New Vessel Disease?

Vascular sequelae following (SARS-CoV-2 coronavirus disease) (COVID)-19 infection are considered as "Long Covid (LC)" disease, when occurring 12 weeks after the original infection. The paucity of specific data can be obviated by translating pathophysiological elements from the original Severe Acute Respiratory Syndrome-Corona Virus (SARS-CoV-2) infection (In a microcirculatory system, a first "endotheliitis," is often followed by production of "Neutrophil Extracellular Trap," and can evolve into a more complex leukocytoklastic-like and hyperimmune vasculitis. In medium/large-sized vessels, this corresponds to endothelial dysfunction, leading to an accelerated progression of pre-existing atherosclerotic plaques through an increased deposition of platelets, circulating inflammatory cells and proteins. Associated dysregulated immune and pro-coagulant conditions can directly cause thrombo-embolic arterial or venous complications. In order to implement appropriate treatment, physicians need to consider vascular pathologies observed after SARS-Cov-2 infections as possible "LC" disease.

Prevalence and risk factors of post-acute sequelae of COVID-19 among United States Veterans

PURPOSE

To better understand Post-Acute Sequelae of COVID-19 (PASC) in the Veteran population, this study aims to determine the prevalence of PASC and identify risk factors associated with its development.

METHODS

This retrospective cohort study included 363,825 Veterans that tested positive for COVID-19 between February 1, 2020, and September 30, 2022. The primary outcome was the development of PASC 30-180 days following an acute infection with SARS-CoV-2. Multivariate logistic regression was utilized to examine factors associated with PASC.

RESULTS

Of the 363,825 Veterans included in the analysis, 164,315 (45%) displayed symptoms of PASC. The Veterans in this analysis were predominantly male, non-Hispanic White, under the age of 65 years old, and lived in an urban residence. The strongest predictors for PASC included Non-Hispanic Black or African American race compared to Non-Hispanic White race (aOR=1.14), being between the ages of 50 and 64 compared to ages 50 and below (aOR=1.80), diabetes (aOR=8.46), and severe acute infection (aOR=1.42).

CONCLUSION

Results demonstrate potential health inequities for vulnerable individuals, as well as increased risk for individuals with pre-existing comorbidities. The prevalence of PASC provides estimates for future health care utilization. The risk factors identified can aid public health interventions to reduce the burden of PASC.

Summarizing Evidence of Associations of COVID-19 With a Future Diagnosis of Inflammatory Rheumatic and Musculoskeletal Diseases: A Rapid Review

OBJECTIVE

Musculoskeletal symptoms are commonly reported following acute COVID-19. It is unclear whether those with musculoskeletal symptoms subsequently develop inflammatory rheumatic musculoskeletal disease (iRMD). This review seeks to identify evidence for an association between acute COVID-19 and subsequent iRMD diagnosis.

METHODS

A rapid review of the literature using a systematic search of Medline, EMBASE and two COVID-19 databases was undertaken until August 2022. Case studies, case series, cross-sectional, case-control, and cohort studies reporting patients with an incident iRMD following COVID-19 were included. Title and abstract screening were conducted by one reviewer and full text screening by two reviewers. Data extraction and quality appraisal were by one reviewer, with a second verifying. Study-type specific critical appraisal tools were used.

RESULTS

Results were narratively synthesized. A total of 80 studies were included (69 case reports, 10 case series and 1 cross-sectional study). Commonly reported iRMDs were "reactive arthropathies" (n = 47), "inflammatory arthropathies unspecified" (n = 18), rheumatoid arthritis (n = 12) and systemic lupus erythematosus (n = 11). The cross-sectional study reported 37% of those with COVID-19 developed "post COVID arthritis." Time from diagnosis of COVID-19 to iRMD presentation ranged from 0 to 120 days. Several mechanisms were proposed to explain the association between COVID-19 and iRMD development: autoimmune processes, aberrant inflammatory responses, colonization of joint spaces, direct damage from the severe acute respiratory syndrome coronavirus 2 virus and genetic predisposition.

CONCLUSION

The level of evidence of the studies included in this review was low and the quality generally poor. Prospective observational studies are required to confirm associations and likely impact of post COVID-19 iRMDs at a population level.

Comparison of Omicron and Delta Variants of SARS-CoV-2: A Systematic Review of Current Evidence

INTRODUCTION

Severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) caused the outbreak of coronavirus disease 2019 (COVID-19) in late 2019 in Wuhan, China. In early 2020, the disease spread rapidly around the world. Since the pandemic, SARS-CoV-2 has evolved dramatically into a wide variety of variants endowed with devastating properties. As of March 6, 2022, five SARS-CoV-2 variants of concern, including Alpha, Beta, Gamma, Delta, and Omicron strains have been identified. Due to the crucial importance of understanding the differences between the Omicron and Delta variants, this systematic review was conducted.

METHODS

This systematic review investigated new variants of Omicron SARS-CoV-2 based on current studies. Online databases were searched for English articles as of January 03, 2023. Selection of publications was a two-step process of title/abstract and full-text assessment against eligibility criteria. The relevant data from the included articles were systematically collected and organized in a designed table for analysis. To ensure the quality of the review, the PRISMA checklist and Newcastle- Ottawa Scale (NOS) of quality assessment were utilized.

RESULTS

The data extracted from 58 articles were analyzed, including 10003 pieces of evidence. Lower risk of hospitalization, ICU admission, and mortality after vaccination were reported in the Omicron variant compared to the Delta variant. Additionally, the Delta variant led to more severe clinical symptoms in comparison to the Omicron variant.

CONCLUSION

The Omicron variant of SARS-CoV-2 results in less severe disease outcomes as compared to Delta. Nevertheless, it remains crucial to maintain ongoing monitoring, implement containment measures, and adapt vaccination protocols to effectively address the evolving variants.

Differential Outcomes of Infection by Wild-Type SARS-CoV-2 and the B.1.617.2 and B.1.1.529 Variants of Concern in K18-hACE2 Transgenic Mice

BACKGROUND

SARS-CoV-2 is a respiratory virus with neurological complications including the loss of smell and taste, headache, and confusion that can persist for months or longer. Severe neuronal cell damage has also been reported in some cases. The objective of this study was to compare the infectivity of the wild-type virus, Delta (B.1.617.2) and Omicron (B.1.1.529) variants in transgenic mice that express the human angiotensin-converting enzyme 2 (hACE2) receptor under the control of the keratin 18 promoter (K18) and characterize the progression of infection and inflammatory response in the lungs, brain, medulla oblongata, and olfactory bulbs of these animals. We hypothesized that wild type, Delta and Omicron differentially infect K18-hACE2 mice, thereby inducing distinct cellular responses.

METHODS

K18-hACE2 female mice were intranasally infected with wild-type, Delta, or Omicron variants and euthanized either at 3 days post-infection (dpi) or at the humane endpoint. None of the animals infected with the Omicron variant reached the humane endpoint and were euthanized at day 8 dpi. Virological and immunological analyses were performed in the lungs, brains, medulla oblongata and olfactory bulbs isolated from infected mice.

RESULTS

At 3 dpi, mice infected with wild type and Delta displayed significantly higher levels of viral RNA in the lungs than mice infected with Omicron, while in the brain, Delta and Omicron resulted in higher levels of viral RNA than with the wild type. Viral RNA was also detected in the medulla oblongata of mice infected by all these virus strains. At this time point, the mice infected with wild type and Delta displayed a marked upregulation of many inflammatory markers in the lungs. On the other hand, the upregulation of inflammatory markers was observed only in the brains of mice infected with Delta and Omicron. At the humane endpoint, we observed a significant increase in the levels of viral RNA in the lungs and brains of mice infected with wild type and Delta, which was accompanied by the elevated expression of many inflammatory markers. In contrast, mice which survived infection with the Omicron variant showed high levels of viral RNA and the upregulation of cytokine and chemokine expression only in the lungs at 8 dpi, suggesting that infection and inflammatory response by this variant is attenuated in the brain. Reduced RNA levels and the downregulation of inflammatory markers was also observed in the medulla oblongata and olfactory bulbs of mice infected with Omicron at 8 dpi as compared with mice infected with wild-type and Delta at the humane end point. Collectively, these data demonstrate that wild-type, Delta, and Omicron SARS-CoV-2 induce distinct levels of infection and inflammatory responses in K18-hACE2 mice. Notably, sustained brain infection accompanied by the upregulation of inflammatory markers is a critical outcome in mice infected with wild type and Delta but not Omicron.

[Сardiac arrhythmias in people who have had a coronavirus infection COVID-19: A review]

Heart rhythm disorders are one of the most common complications of coronavirus infection. Heart rhythm disorders can develop in 6-17% of hospitalized patients, and in convalescents, COVID-19 can manifest itself up to 12 months after the completion of the acute phase of the disease. Among the mechanisms for the development of cardiac arrhythmias, there are a direct cytopathic effect of SARS-CoV-2 on the myocardium, systemic inflammatory response syndrome, electrolyte imbalance, hypoxia, the use of antibacterial, antimalarial and antiviral drugs, exudative pericarditis, autonomic dysfunction. The main COVID-19-mediated heart rhythm disorders are sinus tachycardia and bradycardia, atrial fibrillation, ventricular tachycardia, long QT syndrome. Despite a significant amount of research, the literature data on the prevalence of certain types of cardiac arrhythmias (especially in COVID-19 convalescents), as well as methods for their correction, are somewhat contradictory and need to be clarified. Taking into account the impact of arrhythmia on the quality of life and mortality, active monitoring of convalescents of coronavirus infection, identification and development of approaches to the treatment of heart rhythm disorders in patients who have had COVID-19, seem to be relevant and promising areas in modern cardiology.

Significant burden of post-COVID exertional dyspnoea in a South-Italy region: knowledge of risk factors might prevent further critical overload on the healthcare system

Background

Exertional dyspnoea in post-COVID syndrome is a debilitating manifestation, requiring appropriate comprehensive management. However, limited-resources healthcare systems might be unable to expand their healthcare-providing capacity and are expected to be overwhelmed by increasing healthcare demand. Furthermore, since post-COVID exertional dyspnoea is regarded to represent an umbrella term, encompassing several clinical conditions, stratification of patients with post-COVID exertional dyspnoea, depending on risk factors and underlying aetiologies might provide useful for healthcare optimization and potentially help relieve healthcare service from overload. Hence, we aimed to investigate the frequency, functional characterization, and predictors of post-COVID exertional dyspnoea in a large cohort of post-COVID patients in Apulia, Italy, at 3-month post-acute SARS-CoV-2 infection.

Methods

A cohort of laboratory-confirmed 318 patients, both domiciliary or hospitalized, was evaluated in a post-COVID Unit outpatient setting. Post-COVID exertional dyspnoea and other post-COVID syndrome manifestations were collected by medical history. Functional characterization of post-COVID exertional dyspnoea was performed through a 6-min walking test (6-mwt). The association of post-COVID exertional dyspnoea with possible risk factors was investigated through univariate and multivariate logistic regression analysis.

Results

At medical evaluation, post-COVID exertional dyspnoea was reported by as many as 190/318 patients (59.7%), showing relatively high prevalence also in domiciliary-course patients. However, functional characterization disclosed a 6-mwt-based desaturation walking drop in only 24.1% of instrumental post-COVID exertional dyspnoea patients. Multivariate analysis identified five independent predictors significantly contributing to PCED, namely post-COVID-fatigue, pre-existing respiratory co-morbidities, non-asthmatic allergy history, age, and acute-phase-dyspnoea. Sex-restricted multivariate analysis identified a differential risk pattern for males (pre-existing respiratory co-morbidities, age, acute-phase-dyspnoea) and females (post-COVID-fatigue and acute-phase-dyspnoea).

Conclusion

Our findings revealed that post-COVID exertional dyspnoea is characterized by relevant clinical burden, with potential further strain on healthcare systems, already weakened by pandemic waves. Sex-based subgroup analysis reveals sex-specific dyspnoea-underlying risk profiles and pathogenic mechanisms. Knowledge of sex-specific risk-determining factors might help optimize personalized care management and healthcare resources.

Uncovering a unique pathogenic mechanism of SARS-CoV-2 omicron variant: selective induction of cellular senescence

BACKGROUND

SARS-CoV-2 variants are constantly emerging with a variety of changes in the conformation of the spike protein, resulting in alterations of virus entry mechanisms. Solely omicron variants use the endosomal clathrin-mediated entry. Here, we investigate the influence of defined altered spike formations to study their impact on premature cellular senescence.

METHODS

In our study, in vitro infections of SARS-CoV-2 variants delta (B.1.617.2) and omicron (B.1.1.529) were analyzed by using human primary small alveolar epithelial cells and human ex vivo lung slices. We confirmed cellular senescence in human lungs of COVID-19 patients. Hence, global gene expression patterns of infected human primary alveolar epithelial cells were identified via mRNA sequencing.

RESULTS

Solely omicron variants of SARS-CoV-2 influenced the expression of cell cycle genes, highlighted by an increased p21 expression in human primary lung cells and human ex vivo lungs. Additionally, an upregulated senescence-associated secretory phenotype (SASP) was detected. Transcriptomic data indicate an increased gene expression of p16, and p38 in omicron-infected lung cells.

CONCLUSIONS

Significant changes due to different SARS-CoV-2 infections in human primary alveolar epithelial cells with an overall impact on premature aging could be identified. A substantially different cellular response with an upregulation of cell cycle, inflammation- and integrin-associated pathways in omicron infected cells indicates premature cellular senescence.

Clinical Features and Follow-up of Referred Children and Young People With Long COVID

BACKGROUND

Patient-level data on the clinical features and outcomes of children and young people referred for possible long coronavirus disease (COVID) can guide clinicians on what to expect in managing patients and advising families.

METHODS

A Post-Acute COVID Clinic for persons <21 years of age was established in October 2020. Intake was standardized and management was tailored to presenting symptoms. Data were abstracted from the charts of all patients evaluated through December 2021, and the study cohort consisted of patients who had a history of confirmed severe acute respiratory syndrome coronavirus 2 infection, had ≥1 symptom persisting for ≥12 weeks and had no pre-existing diagnosis that explained the symptoms. A structured follow-up interview was conducted in early 2022.

RESULTS

A total of 104 patients were referred, 81 of whom met inclusion criteria. The median age was 14 years (interquartile range, 13-16), and most were female, White/Caucasian and had commercial health insurance. Patients reported previously good health but over half reported moderate-to-severe disability at their first visit. Two clusters of presenting symptoms-fatigue with multiple symptoms, and fatigue and headache with cardiopulmonary symptoms-were identified. Extensive routine testing did not affirm alternative diagnoses. Incident conditions-most commonly anxiety, depression and/or panic disorder; migraines; and autonomic dysfunction-were diagnosed on clinical grounds. Telephone interviews (N = 55) revealed that 78% of patients were improved by about 6 months.

CONCLUSIONS

Within the limits of a single-center, referral-based, observational cohort, this study provides reassurance to patients and parents in that most cases of long COVID were self-limited. Extensive evaluations may be more useful in ruling out alternative diagnoses than in affirming specific physiologic disturbances.

Long-term prognosis at 1.5 years after infection with wild-type strain of SARS-CoV-2 and Alpha, Delta, as well as Omicron variants

OBJECTIVES

Knowledge is limited on how changing SARS-CoV-2 variants may translate into different characteristics and affect the prognosis of patients with long COVID, especially following Omicron variants. We compared long-term prognosis of patients in a Danish Post-COVID Clinic infected with wild-type strain, Alpha, Delta, or Omicron variants as well as the pre-Omicron compared to the Omicron period.

METHODS

At enrollment, a Post-COVID symptom Questionnaire (PCQ), and standard health scores, were registered and repeated four times until 1.5 years after infection. PCQ was the primary outcome to assess the severity of long COVID, and Delta PCQ to assess failure to improve.

RESULTS

A total of 806 patients were enrolled. Patients infected with Omicron and Delta variants presented with more severe long COVID (median PCQ 43 in Delta vs 38 in wild-type, P = 0.003) and health scores (EuroQol five-dimension five-level-index was 0.70 in Omicron vs 0.76 in wild-type, P = 0.009 and 0.78 pre-Omicron, P = 0.006). At 1.5 years after infection, patients had no clinically meaningful decline in severity of long COVID, and 57% (245/429) of patients failed to improve 1.5 years after infection, with no differences between variants.

CONCLUSION

More than half of patients referred to a Post-COVID Clinic failed to improve in long COVID severity 1.5 years after infection regardless of variants of SARS-CoV-2.

Mechanisms of long COVID: An updated review

The coronavirus disease 2019 (COVID-19) pandemic has been ongoing for more than 3 years, with an enormous impact on global health and economies. In some patients, symptoms and signs may remain after recovery from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, which cannot be explained by an alternate diagnosis; this condition has been defined as long COVID. Long COVID may exist in patients with both mild and severe disease and is prevalent after infection with different SARS-CoV-2 variants. The most common symptoms include fatigue, dyspnea, and other symptoms involving multiple organs. Vaccination results in lower rates of long COVID. To date, the mechanisms of long COVID remain unclear. In this narrative review, we summarized the clinical presentations and current evidence regarding the pathogenesis of long COVID.

True prevalence of long-COVID in a nationwide, population cohort study

Long-COVID prevalence estimates vary widely and should take account of symptoms that would have occurred anyway. Here we determine the prevalence of symptoms attributable to SARS-CoV-2 infection, taking account of background rates and confounding, in a nationwide population cohort study of 198,096 Scottish adults. 98,666 (49.8%) had symptomatic laboratory-confirmed SARS-CoV-2 infections and 99,430 (50.2%) were age-, sex-, and socioeconomically-matched and never-infected. While 41,775 (64.5%) reported at least one symptom 6 months following SARS-CoV-2 infection, this was also true of 34,600 (50.8%) of those never-infected. The crude prevalence of one or more symptom attributable to SARS-CoV-2 infection was 13.8% (13.2%,14.3%), 12.8% (11.9%,13.6%), and 16.3% (14.4%,18.2%) at 6, 12, and 18 months respectively. Following adjustment for potential confounders, these figures were 6.6% (6.3%, 6.9%), 6.5% (6.0%, 6.9%) and 10.4% (9.1%, 11.6%) respectively. Long-COVID is characterised by a wide range of symptoms that, apart from altered taste and smell, are non-specific. Care should be taken in attributing symptoms to previous SARS-CoV-2 infection.

"The burden of post-acute COVID-19 symptoms in a multinational network cohort analysis"

Persistent symptoms following the acute phase of COVID-19 present a major burden to both the affected and the wider community. We conducted a cohort study including over 856,840 first COVID-19 cases, 72,422 re-infections and more than 3.1 million first negative-test controls from primary care electronic health records from Spain and the UK (Sept 2020 to Jan 2022 (UK)/March 2022 (Spain)). We characterised post-acute COVID-19 symptoms and identified key symptoms associated with persistent disease. We estimated incidence rates of persisting symptoms in the general population and among COVID-19 patients over time. Subsequently, we investigated which WHO-listed symptoms were particularly differential by comparing their frequency in COVID-19 cases vs. matched test-negative controls. Lastly, we compared persistent symptoms after first infections vs. reinfections.Our study shows that the proportion of COVID-19 cases affected by persistent post-acute COVID-19 symptoms declined over the study period. Risk for altered smell/taste was consistently higher in patients with COVID-19 vs test-negative controls. Persistent symptoms were more common after reinfection than following a first infection. More research is needed into the definition of long COVID, and the effect of interventions to minimise the risk and impact of persistent symptoms.

Impact of vaccination and variants of concern on long COVID clinical phenotypes

BACKGROUND

Defining patterns of symptoms in long COVID is necessary to advance therapies for this heterogeneous condition. Here we aimed to describe clusters of symptoms in individuals with long COVID and explore the impact of the emergence of variants of concern (VOCs) and vaccination on these clusters.

METHODS

In a prospective, multi centre cohort study, individuals with symptoms persisting > 4 weeks from acute COVID-19 were divided into two groups based on timing of acute infection; pre-Alpha VOC, denoted wild type (WT) group and post-Alpha VOC (incorporating alpha and delta dominant periods) denoted VOC group. We used multiple correspondence analysis (MCA) and hierarchical clustering in the WT and VOC groups to identify symptom clusters. We then used logistic regression to explore factors associated with individual symptoms.

RESULTS

A total of 417 individuals were included in the analysis, 268 in WT and 149 in VOC groups respectively. In both groups MCA identified three similar clusters; a musculoskeletal (MSK) cluster characterised by joint pain and myalgia, a cardiorespiratory cluster and a less symptomatic cluster. Differences in characteristic symptoms were only seen in the cardiorespiratory cluster where a decrease in the frequency of palpitations (10% vs 34% p = 0.008) and an increase in cough (63% vs 17% p < 0.001) in the VOC compared to WT groups was observed. Analysis of the frequency of individual symptoms showed significantly lower frequency of both chest pain (25% vs 39% p = 0.004) and palpitations (12% vs 32% p < 0.001) in the VOC group compared to the WT group. In adjusted analysis being in the VOC group was significantly associated with a lower odds of both chest pain and palpitations, but vaccination was not associated with these symptoms.

CONCLUSION

This study suggests changes in long COVID phenotype in individuals infected later in the pandemic, with less palpitations and chest pain reported. Adjusted analyses suggest that these effects are mediated through introduction of variants rather than an effect from vaccination.

Nirmatrelvir/ritonavir and risk of long COVID symptoms: a retrospective cohort study

We conducted a retrospective cohort study to assess whether treatment with nirmatrelvir/ritonavir was associated with a reduced risk of long COVID. We enrolled 500 adults with confirmed SARS-CoV-2 who were eligible for nirmatrelvir/ritonavir; 250 who took nirmatrelvir/ritonavir and 250 who did not. The primary outcome was the development of one or more of eleven prespecified long COVID symptoms, assessed through a structured telephone interview four months after the positive SARS-CoV-2 test. Multivariable logistic regression models controlled for age, sex, race/ethnicity, chronic conditions, and COVID-19 vaccination status. We found that participants who took nirmatrelvir/ritonavir were no less likely to develop long COVID symptoms, compared to those who did not take the medication (44% vs. 49.6%, p = 0.21). Taking nirmatrelvir/ritonavir was associated with a lower odds of two of the eleven long COVID symptoms, brain fog (OR 0.58, 95% CI 0.38-0.88) and chest pain/tightness (OR 0.51, 95% CI 0.28-0.91). Our finding that treatment with nirmatrelvir/ritonavir was not associated with a lower risk of developing long COVID is different from prior studies that obtained data only from electronic medical records.

Association between SARS-CoV-2 variants and post COVID-19 condition: findings from a longitudinal cohort study in the Belgian adult population

BACKGROUND

While many studies on the determinants of post-COVID-19 conditions (PCC) have been conducted, little is known about the relationship between SARS-CoV-2 variants and PCC. This study aimed to assess the association between different SARS-CoV-2 variants and the probability of having PCC three months after the infection.

METHODS

This study was a longitudinal cohort study conducted between April 2021 and September 2022 in Belgium. In total, 8,238 adults with a confirmed SARS-CoV-2 infection were followed up between the time of their infection and three months later. The primary outcomes were the PCC status three months post infection and seven PCC symptoms categories (neurocognitive, autonomic, gastrointestinal, respiratory, musculoskeletal, anosmia and/or dysgeusia, and other manifestations). The main exposure variable was the type of SARS-CoV-2 variants (i.e. Alpha, Delta, and Omicron), extracted from national surveillance data. The association between the different SARS-CoV-2 variants and PCC as well as PCC symptoms categories was assessed using multivariable logistic regression.

RESULTS

The proportion of PCC among participants infected during the Alpha, Delta, and Omicron-dominant periods was significantly different and respectively 50%, 50%, and 37%. Participants infected during the Alpha- and Delta-dominant periods had a significantly higher odds of having PCC than those infected during the Omicron-dominant period (OR = 1.61, 95% confidence interval [CI] = 1.33-1.96 and OR = 1.73, 95%CI = 1.54-1.93, respectively). Participants infected during the Alpha and Delta-dominant periods were more likely to report neurocognitive, respiratory, and anosmia/dysgeusia symptoms of PCC.

CONCLUSIONS

People infected during the Alpha- and Delta-dominant periods had a higher probability of having PCC three months after infection than those infected during the Omicron-dominant period. The lower probability of PCC with the Omicron variant must also be interpreted in absolute figures. Indeed, the number of infections with the Omicron variant being higher than with the Alpha and Delta variants, it is possible that the overall prevalence of PCC in the population increases, even if the probability of having a PCC decreases.

Gray Matter Thickness and Subcortical Nuclear Volume in Men After SARS-CoV-2 Omicron Infection

Importance

The clinical manifestations and effects on the brain of the SARS-CoV-2 Omicron variant in the acute postinfection phase remain unclear.

Objective

To investigate the pathophysiological mechanisms underlying clinical symptoms and changes to gray matter and subcortical nuclei among male patients after Omicron infection and to provide an imaging basis for early detection and intervention.

Design, Setting, and Participants

In this cohort study, a total of 207 men underwent health screening magnetic resonance imaging scans between August 28 and September 18, 2022; among them, 98 provided complete imaging and neuropsychiatric data. Sixty-one participants with Omicron infection were reevaluated after infection (January 6 to 14, 2023). Neuropsychiatric data, clinical symptoms, and magnetic resonance imaging data were collected in the acute post-Omicron period, and their clinical symptoms were followed up after 3 months. Gray matter indexes and subcortical nuclear volumes were analyzed. Associations between changes in gray matter and neuropsychiatric data were evaluated with correlation analyses.

Exposures

Gray matter thickness and subcortical nuclear volume change data were compared before and after Omicron infection.

Main Outcomes and Measures

The gray matter indexes and subcutaneous nuclear volume were generated from the 3-dimensional magnetization-prepared rapid acquisition gradient echo and were calculated with imaging software.

Results

Ninety-eight men underwent complete baseline data collection; of these, 61 (mean [SD] age, 43.1 [9.9] years) voluntarily enrolled in post-Omicron follow-up and 17 (mean [SD] age, 43.5 [10.0] years) voluntarily enrolled in 3-month follow-up. Compared with pre-Omicron measures, Beck Anxiety Inventory scores were significantly increased (median, 4.50 [IQR, 1.00-7.00] to 4.00 [IQR, 2.00-9.75]; P = .006) and depressive distress scores were significantly decreased (median, 18.00 [IQR, 16.00-20.22] to 16.00 [IQR, 15.00-19.00]; P = .003) at the acute post-Omicron follow-up. Fever, headache, fatigue, myalgia, cough, and dyspnea were the main symptoms during the post-Omicron follow-up; among the participants in the 3-month follow-up, fever (11 [64.7%] vs 2 [11.8%]; P = .01), myalgia (10 [58.8%] vs 3 (17.6%]; P = .04), and cough (12 [70.6%] vs 4 [23.5%]; P = .02) were significantly improved. The gray matter thickness in the left precuneus (mean [SD], 2.7 [0.3] to 2.6 [0.2] mm; P < .001) and right lateral occipital region (mean [SD], 2.8 [0.2] to 2.7 [0.2] and 2.5 [0.2] to 2.5 [0.2] mm; P < .001 for both) and the ratio of the right hippocampus volume to the total intracranial volume (mean [SD]. 0.003 [0.0003] to 0.003 [0.0002]; P = .04) were significantly reduced in the post-Omicron follow-up. The febrile group had reduced sulcus depth of the right inferior parietal region compared with the nonfebrile group (mean [SD], 3.9 [2.3] to 4.8 [1.1]; P = .048. In the post-Omicron period, the thickness of the left precuneus was negatively correlated with the Beck Anxiety Inventory scores (r = -0.39; P = .002; false discovery rate P = .02), and the ratio of the right hippocampus to the total intracranial volume was positively correlated with the Word Fluency Test scores (r = 0.34; P = .007).

Conclusions and Relevance

In this cohort study of male patients infected with the Omicron variant, the duration of symptoms in multiple systems after infection was short. Changes in gray matter thickness and subcortical nuclear volume injury were observed in the post-Omicron period. These findings provide new insights into the emotional and cognitive mechanisms of an Omicron infection, demonstrate its association with alterations to the nervous system, and verify an imaging basis for early detection and intervention of neurological sequelae.

Association between virus variants, vaccination, previous infections, and post-COVID-19 risk

OBJECTIVES

The SARS-CoV-2 Omicron variant has spread rapidly and has been the dominant variant since 2022. The course of acute infection, in a vaccinated population, with Omicron is milder compared with earlier variants. However, little is known about how the occurrence of long-term symptoms after Omicron infection compared with other variants is modulated by previous infections and/or vaccinations.

METHODS

Participants of the DigiHero study provided information about their SARS-CoV-2 infections, vaccinations, and symptoms 12 or more weeks after infection (post-COVID-19 condition - PCC).

RESULTS

Participants infected with wildtype SARS-CoV-2 had the highest PCC risk (adjusted odds ratio [aOR] 6.44, 95% confidence interval (CI): 5.49; 7.56), followed by participants infected with Alpha and Delta compared with the reference group (individuals infected with Omicron having received three or more vaccinations). Among those infected with a specific variant, the number of preceding vaccinations was not associated with a risk reduction for PCC, whereas previous infection was strongly associated with a lower PCC risk (aOR 0.14, 95% CI 0.07; 0.25).

CONCLUSIONS

While infection with Omicron is less likely to result in PCC compared with previous variants, lack of protection by vaccination suggests a substantial challenge for the healthcare system during the early endemic period. In the midterm, the protective effects of previous infections can reduce the burden of PCC.

Prevalence and predictors of post-COVID-19 symptoms in general practice - a registry-based nationwide study

BACKGROUND

With Norwegian national registry data, we assessed the prevalence of post-COVID-19 symptoms at least 3 months after confirmed infection, and whether sociodemographic factors and pre-pandemic health problems were risk factors for these symptoms.

METHODS

All persons with a positive SARS-CoV-2 PCR test from February 2020 to February 2021 (exposed) were compared to a group without a positive test (unexposed) matched on age, sex, and country of origin. We used Cox regression to estimate hazard ratios (HR) for 18 outcome symptoms commonly described as post-COVID-19 related, registered by GPs. We compared relative risks (RR) for fatigue, memory disturbance, or shortness of breath among exposed and unexposed using Poisson regression models, assessing sex, age, education, country of origin, and pre-pandemic presence of the same symptom and comorbidity as possible risk factors, with additional analyses to assess hospitalisation for COVID-19 as a risk factor among exposed.

RESULTS

The exposed group (N = 53 846) had a higher prevalence of most outcome symptoms compared to the unexposed (N = 485 757), with the highest risk for shortness of breath (HR 2.75; 95%CI 2.59-2.93), fatigue (2.08; 2.00-2.16) and memory disturbance (1.41;1.26-1.59). High HRs were also found for disturbance of smell/taste and hair loss, but frequencies were low. Concerning risk factors, sociodemographic factors were at large similarly associated with outcome symptoms in both groups. Registration of the outcome symptom before the pandemic increased the risk for fatigue, memory disturbance and shortness of breath after COVID-19, but these associations were weaker among exposed. Comorbidity was not associated with fatigue and shortness of breath in the COVID-19 group. For memory disturbance, the RR was slightly increased with the higher comorbidity score both among exposed and unexposed.

CONCLUSION

COVID-19 was associated with a range of symptoms lasting more than three months after the infection.