Prevalence of Post-Coronavirus Disease Condition 12 Weeks After Omicron Infection Compared With Negative Controls and Association With Vaccination Status

Postacute Sequelae of COVID (PASC or Long COVID): An Evidenced-Based Approach

While the acute manifestations of infectious diseases are well known, in some individuals, symptoms can either persist or appear after the acute period. Postviral fatigue syndromes are recognized with other viral infections and are described after coronavirus disease 2019 (COVID-19). We have a growing number of individuals with symptoms that persist for weeks, months, and years. Here, we share the evidence regarding the abnormalities associated with postacute sequelae of COVID-19 (PASC) and therapeutics. We describe physiological and biochemical abnormalities seen in individuals reporting PASC. We describe the several evidence-based interventions to offer patients. It is expected that this growing understanding of the mechanisms driving PASC and the benefits seen with certain therapeutics may not only lead to better outcomes for those with PASC but may also have the potential for understanding and treating other postinfectious sequelae.

Prevalence of and Risk Factors for Post-COVID-19 Condition during Omicron BA.5-Dominant Wave, Japan

The increased risk for post-COVID-19 condition after the Omicron-dominant wave remains unclear. This population-based study included 25,911 persons in Japan 20-69 years of age with confirmed SARS-CoV-2 infection enrolled in the established registry system during July-August 2022 and 25,911 age- and sex-matched noninfected controls who used a self-reported questionnaire in January-February 2023. We compared prevalence and age- and sex-adjusted odds ratios of persistent COVID-19 symptoms (lasting ≥2 months). We evaluated factors associated with post-COVID-19 condition by comparing cases with and without post-COVID-19 condition. We analyzed 14,710 (8,392 cases and 6,318 controls) of 18,183 respondents. Post-COVID-19 condition proportion among cases was 11.8%, higher by 6.3% than 5.5% persistent symptoms among controls. Female sex, underlying medical conditions, mild to moderate acute COVID-19, and vaccination were associated with post-COVID-19 condition. Approximately 12% had post-COVID-19 condition during the Omicron-dominant wave, indicating the need for longer follow-up.

Lower prevalence of post-Covid-19 Condition following Omicron SARS-CoV-2 infection

Objectives

Different SARS-CoV-2 variants can differentially affect the prevalence of Post Covid-19 Condition (PCC). This prospective study assesses prevalence and severity of symptoms three months after an Omicron infection, compared to Delta, test-negative and population controls. This study also assesses symptomology after reinfection and breakthrough infections.

Methods

After a positive SARS-CoV-2 test, cases were classified as Omicron or Delta based on ≥ 85% surveillance prevalence. Three months after enrolment, participants indicated point prevalence for 41 symptoms and severity, using validated questionnaires for four symptoms. PCC prevalence was estimated as the difference in prevalence of at least one significantly elevated symptom, identified by permutation test, in cases compared to population controls.

Results

At three months follow-up, five symptoms and severe dyspnea were significantly elevated in Omicron cases (n = 4138) compared to test-negative (n = 1672) and population controls (n = 2762). PCC prevalence was 10·4% for Omicron cases and 17·7% for Delta cases (n = 6855). In Omicron cases, severe fatigue and dyspnea were more prevalent in reinfected than primary infected, while severity of symptoms did not significantly differ between cases with a booster or primary vaccination course.

Conclusions

Prevalence of PCC is 41% lower after Omicron than Delta at three months. Reinfection seems associated with more severe long-term symptoms compared to first infection.

The impact of COVID-19 vaccination prior to SARS-CoV-2 infection on prevalence of long COVID among a population-based probability sample of Michiganders, 2020-2022

PURPOSE

To estimate the association between COVID-19 vaccination status at the time of COVID-19 onset and long COVID prevalence.

METHODS

We used data from the Michigan COVID-19 Recovery Surveillance Study, a population-based probability sample of adults with COVID-19 (n = 4695). We considered 30-day and 90-day long COVID (illness duration ≥30 or ≥90 days, respectively), using Poisson regression to estimate prevalence ratios (PRs) comparing vaccinated (completed an initial series ≥14 days before COVID-19 onset) to unvaccinated individuals (received 0 doses before COVID-19 onset), accounting for differences in age, sex, race and ethnicity, education, employment, health insurance, and rurality/urbanicity. The full unvaccinated comparison group was further divided into historic and concurrent comparison groups based on timing of COVID-19 onset relative to vaccine availability. We used inverse probability of treatment weights to account for sociodemographic differences between groups.

RESULTS

Compared to the full unvaccinated comparison group, the adjusted prevalence of 30-day and 90-day long COVID were lower among vaccinated individuals [PR30-day= 0.57(95%CI:0.49,0.66); PR90-day= 0.42(95%CI:0.34,0.53)]. Estimates were consistent across comparison groups (full, historic, and concurrent).

CONCLUSIONS

Long COVID prevalence was 40-60% lower among adults vaccinated (vs. unvaccinated) prior to their COVID-19 onset. COVID-19 vaccination may be an important tool to reduce the burden of long COVID.

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.

Reduction in Long COVID Symptoms and Symptom Severity in Vaccinated Compared to Unvaccinated Adults

Background

The impact of vaccination prior to infection on postacute sequelae of coronavirus disease 2019 (COVID-19, PASC), also known as long COVID, remains unclear. Here we assess the protective effect of vaccination on long COVID in a community-based setting.

Methods

The Immunity Associated with SARS-CoV-2 (IASO) study is an ongoing prospective cohort of working adults that began in October 2020. Participants are actively followed for severe acute respiratory syndrome coronavirus 2 infection. We compared the prevalence of symptoms and symptom severity in vaccinated compared to unvaccinated cases. Our primary definition of long COVID was the presence of symptoms at 90 days postinfection; 30 days postinfection was also examined.

Results

Overall, by 90 days postinfection, 13% of cases had long COVID, with 27% of unvaccinated cases and 8% of vaccinated cases reporting long COVID (relative risk [RR], 0.31 [95% confidence interval {CI}, .22-.42]). Vaccination was also associated with significantly lower average severity scores at all timepoints (eg, relative severity at 90 days postinfection: -2.70 [95% CI, -1.68 to -3.73]). In the pre-Omicron era, 28% of unvaccinated cases and 18% of vaccinated cases reported long COVID (P = .07), and vaccinated cases reported less severe symptoms including less difficulty breathing (P = .01; 90-day RR, 0.07).

Conclusions

Vaccinated cases had lower prevalence of long COVID and reduced symptom severity.

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.

Characterisation, symptom pattern and symptom clusters from a retrospective cohort of Long COVID patients in primary care in Catalonia

BACKGROUND

Around 10% of people infected by SARS-COV-2 report symptoms that persist longer than 3 months. Little has been reported about sex differences in symptoms and clustering over time of non-hospitalised patients in primary care settings.

METHODS

This is a descriptive study of a cohort of mainly non-hospitalized patients with a persistence of symptoms longer than 3 months from the clinical onset in co-creation with the Long Covid Catalan affected group using an online survey. Recruitment was from March 2020 to June 2021. Exclusion criteria were being admitted to an ICU, < 18 years of age and not living in Catalonia. We focused on 117 symptoms gathered in 18 groups and performed cluster analysis over the first 21 days of infection, at 22-60 days, and ≥ 3 months.

RESULTS

We analysed responses of 905 participants (80.3% women). Median time between symptom onset and the questionnaire response date was 8.7 months. General symptoms (as fatigue) were the most prevalent with no differences by sex, age, or wave although its frequency decreased over time (from 91.8 to 78.3%). Dermatological (52.1% in women, 28.5% in men), olfactory (34.9% women, 20.9% men) and neurocognitive symptoms (70.1% women, 55.8% men) showed the greatest differences by sex. Cluster analysis showed five clusters with a predominance of Taste & smell (24.9%) and Multisystemic clusters (26.5%) at baseline and _Multisystemic (34.59%) and Heterogeneous (24.0%) at ≥3 months. The Multisystemic cluster was more prevalent in men. The Menstrual cluster was the most stable over time, while most transitions occurred from the Heterogeneous cluster to the Multisystemic cluster and from Taste & smell to Heterogeneous.

CONCLUSIONS

General symptoms were the most prevalent in both sexes at three-time cut-off points. Major sex differences were observed in dermatological, olfactory and neurocognitive symptoms. The increase of the Heterogeneous cluster might suggest an adaptation to symptoms or a non-specific evolution of the condition which can hinder its detection at medical appointments. A carefully symptom collection and patients' participation in research may generate useful knowledge about Long Covid presentation in primary care settings.

Long COVID Prevalence and the Impact of the Third SARS-CoV-2 Vaccine Dose: A Cross-Sectional Analysis from the Third Follow-Up of the Borriana Cohort, Valencia, Spain (2020-2022)

BACKGROUND

In March 2020, a COVID-19 outbreak linked to mass gathering dinners at the Falles Festival in Borriana, Spain, resulted in an estimated attack rate of 42.6% among attendees.

METHODS

In June 2022, we conducted a cross-sectional follow-up study of 473 adults aged 18 to 64 who attended the dinners at the Falles Festival in 2020, examining the cumulative experience after SARS-CoV-2 infection and vaccination responses. Data included demographic details, lifestyle habits, medical history, infection records, and vaccinations from a population-based vaccine registry. Blood samples were analyzed for SARS-CoV-2 antibodies and cellular immunity. We employed a doubly robust inverse-probability weighting analysis to estimate the booster vaccine dose's impact on long COVID prevalence and symptom count.

RESULTS

A total of 28.1% of participants met the WHO criteria for long COVID, with older individuals showing higher rates. Long COVID diagnosis was less likely with factors including O blood group, higher occupational status, physical activity, three vaccine doses, strong SARS-CoV-2-S-reactive IFNγ-producing-CD8+ response, and infection during the Omicron period. Increased age, high or low social activity, underlying health conditions, a severe initial COVID episode, and reinfection were associated with higher long COVID likelihood. A booster dose, compared to one or two doses, reduced long COVID risk by 74% (95% CI: 56% to 92%) and symptom count by 55% (95% CI: 32% to 79%).

CONCLUSION

Long COVID was prevalent in a significant portion of those who contracted COVID-19, underscoring the need for sustained follow-up and therapeutic strategies. Vaccinations, notably the booster dose, had a substantial beneficial effect on long-term infection outcomes, affirming the vaccination's role in mitigating SARS-CoV-2 infection consequences.

Paxlovid as a potential treatment for long COVID

INTRODUCTION

On 31 July 2023, the United States Department of Health and Human Services announced the formation of the Office of Long COVID Research and Practice and the United States National Institutes of Health opened enrollment for RECOVER-Vital, a randomized study to evaluate new treatment options for long Coronavirus (long COVID).

AREAS COVERED

The RECOVER Initiative is a $1.15 billion research platform intended to describe, categorize, treat, and prevent long-term symptoms following infection by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS‑CoV‑2), the virus that causes Coronavirus (COVID-19). More than 200 symptoms have been associated with long COVID, potentially affecting nearly all body systems, and current estimates suggest that between 7 million and 23 million Americans have developed long COVID. However, there are no approved treatments for this condition.

EXPERT OPINION

The first prospective, randomized study of the RECOVER research initiative, RECOVER-Vital, will evaluate the SARS-CoV-2 antiviral nirmatrelvir/ritonavir (Paxlovid) as a potential treatment for long COVID. This manuscript explores what is known about Paxlovid to treat and prevent long COVID and examines the rationale for addressing this condition with an antiviral agent.

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

This review proposes a model of Long-COVID where the constellation of symptoms are in fact genuinely experienced persistent physical symptoms that are usually functional in nature and therefore potentially reversible, that is, Long-COVID is a somatic symptom disorder. First, we describe what is currently known about Long-COVID in children and adults. Second, we examine reported "Long-Pandemic" effects that create a risk for similar somatic symptoms to develop in non-COVID-19 patients. Third, we describe what was known about somatization and somatic symptom disorder before the COVID-19 pandemic, and suggest that by analogy, Long-COVID may best be conceptualized as one of these disorders, with similar symptoms and predisposing, precipitating, and perpetuating factors. Fourth, we review the phenomenon of mass sociogenic (functional) illness, and the concept of nocebo effects, and suggest that by analogy, Long-COVID is compatible with these descriptions. Fifth, we describe the current theoretical model of the mechanism underlying functional disorders, the Bayesian predictive coding model for perception. This model accounts for moderators that can make symptom inferences functionally inaccurate and therefore can explain how to understand common predisposing, precipitating, and perpetuating factors. Finally, we discuss the implications of this framework for improved public health messaging during a pandemic, with recommendations for the management of Long-COVID symptoms in healthcare systems. We argue that the current public health approach has induced fear of Long-COVID in the population, including from constant messaging about disabling symptoms of Long-COVID and theorizing irreversible tissue damage as the cause of Long-COVID. This has created a self-fulfilling prophecy by inducing the very predisposing, precipitating, and perpetuating factors for the syndrome. Finally, we introduce the term "Pandemic-Response Syndrome" to describe what previously was labeled Long-COVID. This alternative perspective aims to stimulate research and serve as a lesson learned to avoid a repeat performance in the future.

Longterm course of neuropsychological symptoms and ME/CFS after SARS-CoV-2-infection: a prospective registry study

A significant proportion of patients after SARS-CoV-2 infection suffer from long-lasting symptoms. Although many different symptoms are described, the majority of patients complains about neuropsychological symptoms. Additionally, a subgroup of patients fulfills diagnostic criteria for ME/CFS. We analyzed a registry of all patients presenting in the out-patients clinic at a German university center. For patients with more than one visit, changes in reported symptoms from first to second visit were analyzed. A total of 1022 patients were included in the study, 411 of them had more than one visit. 95.5% of the patients reported a polysymptomatic disease. At the first visit 31.3% of the patients fulfilled ME/CFS criteria after a median time of 255 days post infection and and at the second visit after a median of 402 days, 19.4% still suffered from ME/CFS. Self-reported fatigue (83.7-72.7%) and concentration impairment (66.2-57.9%) decreased from first to second visit contrasting non-significant changes in the structured screening. A significant proportion of SARS-CoV-2 survivors presenting with ongoing symptoms present with ME/CFS. Although the proportion of subjective reported symptoms and their severity reduce over time, a significant proportion of patients suffer from long-lasting symptoms necessitating new therapeutic concepts.

Post-Acute Sequelae After Severe Acute Respiratory Syndrome Coronavirus 2 Infection by Viral Variant and Vaccination Status: A Multicenter Cross-Sectional Study

BACKGROUND

Disentangling the effects of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants and vaccination on the occurrence of post-acute sequelae of SARS-CoV-2 (PASC) is crucial to estimate and reduce the burden of PASC.

METHODS

We performed a cross-sectional analysis (May/June 2022) within a prospective multicenter healthcare worker (HCW) cohort in north-eastern Switzerland. HCWs were stratified by viral variant and vaccination status at time of their first positive SARS-CoV-2 nasopharyngeal swab. HCWs without positive swab and with negative serology served as controls. The sum of 18 self-reported PASC symptoms was modeled with univariable and multivariable negative-binomial regression to analyze the association of mean symptom number with viral variant and vaccination status.

RESULTS

Among 2912 participants (median age: 44 years; 81.3% female), PASC symptoms were significantly more frequent after wild-type infection (estimated mean symptom number: 1.12; P < .001; median time since infection: 18.3 months), after Alpha/Delta infection (0.67 symptoms; P < .001; 6.5 months), and after Omicron BA.1 infections (0.52 symptoms; P = .005; 3.1 months) versus uninfected controls (0.39 symptoms). After Omicron BA.1 infection, the estimated mean symptom number was 0.36 for unvaccinated individuals versus 0.71 with 1-2 vaccinations (P = .028) and 0.49 with ≥3 prior vaccinations (P = .30). Adjusting for confounders, only wild-type (adjusted rate ratio [aRR]: 2.81; 95% confidence interval [CI]: 2.08-3.83) and Alpha/Delta infections (aRR: 1.93; 95% CI: 1.10-3.46) were significantly associated with the outcome.

CONCLUSIONS

Previous infection with pre-Omicron variants was the strongest risk factor for PASC symptoms among our HCWs. Vaccination before Omicron BA.1 infection was not associated with a clear protective effect against PASC symptoms in this population.

Laboratory Findings and Biomarkers in Long COVID: What Do We Know So Far? Insights into Epidemiology, Pathogenesis, Therapeutic Perspectives and Challenges

Long COVID (LC) encompasses a constellation of long-term symptoms experienced by at least 10% of people after the initial SARS-CoV-2 infection, and so far it has affected about 65 million people. The etiology of LC remains unclear; however, many pathophysiological pathways may be involved, including viral persistence; a chronic, low-grade inflammatory response; immune dysregulation and a defective immune response; the reactivation of latent viruses; autoimmunity; persistent endothelial dysfunction and coagulopathy; gut dysbiosis; hormonal and metabolic dysregulation; mitochondrial dysfunction; and autonomic nervous system dysfunction. There are no specific tests for the diagnosis of LC, and clinical features including laboratory findings and biomarkers may not specifically relate to LC. Therefore, it is of paramount importance to develop and validate biomarkers that can be employed for the prediction, diagnosis and prognosis of LC and its therapeutic response, although this effort may be hampered by challenges pertaining to the non-specific nature of the majority of clinical manifestations in the LC spectrum, small sample sizes of relevant studies and other methodological issues. Promising candidate biomarkers that are found in some patients are markers of systemic inflammation, including acute phase proteins, cytokines and chemokines; biomarkers reflecting SARS-CoV-2 persistence, the reactivation of herpesviruses and immune dysregulation; biomarkers of endotheliopathy, coagulation and fibrinolysis; microbiota alterations; diverse proteins and metabolites; hormonal and metabolic biomarkers; and cerebrospinal fluid biomarkers. At present, there are only two reviews summarizing relevant biomarkers; however, they do not cover the entire umbrella of current biomarkers, their link to etiopathogenetic mechanisms or the diagnostic work-up in a comprehensive manner. Herein, we aim to appraise and synopsize the available evidence on the typical laboratory manifestations and candidate biomarkers of LC, their classification based on pathogenetic mechanisms and the main LC symptomatology in the frame of the epidemiological and clinical aspects of the syndrome and furthermore assess limitations and challenges as well as potential implications in candidate therapeutic interventions.

Variations and Predictors of Post-COVID Syndrome Severity in Patients Attending a Post-COVID Outpatient Clinic

A relevant proportion of patients suffer from long-lasting impairments following an acute SARS-CoV-2 infection. The proposed post-COVID syndrome (PCS) score may improve comparison in the course and classification of affected patients. A prospective cohort of 952 patients presenting to the post-COVID outpatient clinic at Jena University Hospital, Germany, was enrolled. Patients received a structured examination. PCS score was calculated per visit. A total of 378 (39.7%) and 129 (13.6%) patients of the entire population visited the outpatient clinic two or three times, respectively (female: 66.4%; age: 49.5 (SD = 13) years). The initial presentation took place, on average, 290 (SD = 138) days after acute infection. The most frequently reported symptoms were fatigue (80.4%) and neurological impairments (76.1%). The mean PCS scores of patients with three visits were 24.6 points (SD = 10.9), 23.0 points (SD = 10.9) and 23.5 points (SD = 11.5) (p = 0.407), indicating moderate PCS. Female sex (p < 0.001), preexisting coagulation disorder (p = 0.021) and coronary artery disease (p = 0.032) were associated with higher PCS scores. PCS is associated with a multitude of long-lasting problems. The PCS score has proven its capability to objectify and quantify PCS symptoms in an outpatient setting. The influence of therapeutic measures on various PCS aspects should be the subject of further analyses.