Reinfection with SARS-CoV-2 in the Omicron Era is Associated with Increased Risk of Post-Acute Sequelae of SARS-CoV-2 Infection: A RECOVER-EHR Cohort Study

Abstract:

Importance: Post-acute sequelae of SARS-CoV-2 infection (PASC) remains a major public health challenge. While previous studies have focused on characterizing PASC and identifying its subphenotypes in children and adolescents following an initial SARS-CoV-2 infection, the risks of PASC with Omicron-variant reinfections remain unclear. Using a real-world data approach, this study investigates the risks of PASC following reinfections during the Omicron phase in the pediatric population.

Objective: To investigate the risks of PASC diagnosis and 24 PASC symptoms and conditions after reinfection of SARS-CoV-2 during Omicron period in the pediatric population.

Design setting and participants: This retrospective cohort study used data from the RECOVER consortium comprising 40 children’s hospitals and health institutions in U.S. between January 2022 and October 2023.

Exposures: A second SARS-CoV-2 infection, confirmed by a positive polymerase-chain-reaction (PCR) or antigen tests, or a diagnose of COVID-19, occurring at least 60 days after the initial infection, compared to the initial infection.

Main outcomes and measures: PASC was identified using two approaches: (1) the ICD-10-CM diagnosis code U09.9 and (2) a symptom-based definition including 24 physician-identified symptoms and conditions. Absolute risks of incident PASC were reported, and relative risks (RRs) were calculated by comparing the second infection episode with the first infection episode groups using a modified Poisson regression model, adjusting for demographic, clinical, and healthcare utilization factors through exact matching and propensity scoring matching.

Results: A total of 465,717 individuals under 21 years old (mean [SD] age 8.17 [6.58] years; 52% male) were included. Compared to the first infection, a second infection was associated with significantly increased risk of an overall PASC diagnosis (RR, 2.08; 95% confidence interval [CI], 1.68-2.59), and with many specific conditions including: myocarditis (RR, 3.60; 95% CI, 1.46-8.86); changes in taste and smell (RR, 2.83; 95% CI, 1.41-5.67); thrombophlebitis and thromboembolism (RR, 2.28; 95% CI, 1.71-3.04); heart disease (RR, 1.96; 95% CI, 1.69 to 2.28); acute kidney injury (RR, 1.90; 95% CI, 1.38 to 2.61); fluid and electrolyte (RR, 1.89; 95% CI, 1.62 to 2.20); generalized pain (RR, 1.70; 95% CI, 1.48 to ; arrhythmias (RR, 1.59; 95% CI, 1.45-1.74); abnormal liver enzyme (RR, 1.56; 95% CI, 1.24 to ; fatigue and malaise (RR, 1.50; 95% CI, 1.38 to 1.64); musculoskeletal pain (RR, 1.45; 95% CI, 1.37 to 1.54); abdominal pain (RR, 1.42; 95% CI, 1.34 to 1.50); postural orthostatic tachycardia syndromes (POTS)/dysautonomia (RR, 1.35; 95% CI, 1.20 to 1.51); cognitive functions (RR, 1.32; 95% CI, 1.15 to 1.50); and respiratory signs and symptoms (RR, 1.29; 95% CI, 1.25 to 1.33). The risks were consistent across various organ systems, including cardiovascular, respiratory, gastrointestinal, neurological, and musculoskeletal systems.

Conclusions and relevance: Children and adolescents face significantly higher risk of various PASC outcomes after reinfection with SARS-CoV-2. These findings suggest a cumulative risk of PASC and highlight the urgent need for targeted prevention strategies to reduce reinfections, which includes an increased emphasis on initial or re-vaccination of children.

Source: Zhang B, Wu Q, Jhaveri R, Zhou T, Becich MJ, Bisyuk Y, Blanceró F, Chrischilles EA, Chuang CH, Cowell LG, Fort D, Horowitz CR, Kim S, Ladino N, Liebovitz DM, Liu M, Mosa ASM, Schwenk HT, Suresh S, Taylor BW, Williams DA, Morris JS, Forrest CB, Chen Y. Reinfection with SARS-CoV-2 in the Omicron Era is Associated with Increased Risk of Post-Acute Sequelae of SARS-CoV-2 Infection: A RECOVER-EHR Cohort Study. medRxiv [Preprint]. 2025 Mar 30:2025.03.28.25324858. doi: 10.1101/2025.03.28.25324858. PMID: 40196285; PMCID: PMC11974971. https://pmc.ncbi.nlm.nih.gov/articles/PMC11974971/ (Full text)

Long COVID associated with SARS-CoV-2 reinfection among children and adolescents in the omicron era (RECOVER-EHR): a retrospective cohort study

Summary:

Background: Post-acute sequelae of SARS-CoV-2 infection (PASC) remain a major public health challenge. Although previous studies have focused on characterising PASC in children and adolescents after an initial infection, the risks of PASC after reinfection with the omicron variant remain unclear. We aimed to assess the risk of PASC diagnosis (U09.9) and symptoms and conditions potentially related to PASC in children and adolescents after a SARS-CoV-2 reinfection during the omicron period.

Methods: This retrospective cohort study used data from 40 children’s hospitals and health institutions in the USA participating in the Researching COVID to Enhance Recovery (RECOVER) Initiative. We included patients younger than 21 years at the time of cohort entry; with documented SARS-CoV-2 infection after Jan 1, 2022; and who had at least one health-care visit within 24 months to 7 days before the first infection. The second SARS-CoV-2 infection was confirmed by positive PCR, antigen tests, or a diagnosis of COVID-19 that occurred at least 60 days after the first infection. The primary endpoint was a clinician-documented diagnosis of PASC (U09.9). Secondary endpoints were 24 symptoms and conditions previously identified as being potentially related to PASC. We used the modified Poisson regression model to estimate the relative risk (RR) between the second and first infection episodes, adjusted for demographic, clinical, and health-care utilisation factors using exact and propensity-score matching.

Findings: We identified 407 300 (87·5%) of 465 717 eligible children and adolescents with a first infection episode and 58 417 (12·5%) with a second infection episode from Jan 1, 2022, to Oct 13, 2023, in the RECOVER database. 233 842 (50·2%) patients were male and 231 875 (49·8%) were female. The mean age was 8·17 years (SD 6·58). The incident rate of PASC diagnosis (U09.9) per million people per 6 months was 903·7 (95% CI 780·9–1026·5) in the first infection group and 1883·7 (1565·1–2202·3) in the second infection group. Reinfection was associated with a significantly increased risk of an overall PASC diagnosis (U09.9) (RR 2·08 [1·68–2·59]) and a range of symptoms and conditions potentially related to PASC (RR range 1·15–3·60), including myocarditis, changes in taste and smell, thrombophlebitis and thromboembolism, heart disease, acute kidney injury, fluid and electrolyte disturbance, generalised pain, arrhythmias, abnormal liver enzymes, chest pain, fatigue and malaise, headache, musculoskeletal pain, abdominal pain, mental ill health, POTS or dysautonomia, cognitive impairment, skin conditions, fever and chills, respiratory signs and symptoms, and cardiovascular signs and symptoms.

Interpretation: Children and adolescents face a significantly higher risk of various PASC outcomes after reinfection with SARS-CoV-2. These findings add to previous evidence linking paediatric long COVID to multisystem effects and highlight the need to promote vaccination in younger populations and support ongoing research to better understand PASC, identify high-risk subgroups, and improve prevention and care strategies.

Funding: National Institutes of Health.

Source: Zhang, Bingyu et al. Long COVID associated with SARS-CoV-2 reinfection among children and adolescents in the omicron era (RECOVER-EHR): a retrospective cohort study. The Lancet Infectious Diseases, Volume 0, Issue 0, Online first; September 30, 2025. https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(25)00476-1/fulltext (Full text)

Exploration of Intersections and Divergences of Long COVID and Chronic Fatigue Syndrome

Abstract:

Background: Fatigue is the most common symptom of Long COVID (LC), defined by persistent or newly emerging symptoms that develop at least three months after an initial SARS-CoV-2 infection, in the absence of other identifiable cause. This study investigates the prevalence of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) as a potential comorbidity of LC.

Methods: The study enrolled 37 adult controls with no documented SARS-CoV-2 infection and 32 individuals with a history of infection, categorized as LC-yes (with LC symptoms) and LC-no (without LC symptoms). ME/CFS diagnosis was based on the International Consensus Criteria (ICC).

Results: Among LC-yes cases, the most frequently reported symptoms included post-exertional malaise (PEM); neurosensory, perceptual, or motor disturbances; cognitive impairment; sleep disturbances; pain; impaired thermoregulation; and flu-like symptoms, all occurring significantly more than in the LC-no or control groups. All individuals in the LC-yes group reported PEM. ME/CFS was diagnosed in three LC-yes cases (18.8%), one LC-no case (6.7%), and four control subjects (10.8%), with no statistically significant differences observed among groups. Experiencing more than six symptoms during acute infection, such as fatigue, loss of taste or smell, headache, fever, cough, myalgia, sore throat, shortness of breath, rhinorrhea, and diarrhea, was associated with a twofold higher risk of developing LC.

Conclusion: A substantial proportion of LC-yes individuals experienced PEM; neurosensory, perceptual, or motor disturbances; cognitive impairment; and sleep disturbances, with rates significantly exceeding those in the LC-no and control groups. Nevertheless, only a minority of LC-yes cases (18.8%) satisfied criteria for the ME/CFS, and the prevalence did not significantly differ from LC-no and controls. These findings suggest that while many symptoms of LC overlap with those of ME/CFS, only a subset of LC cases meet established ME/CFS diagnostic criteria.

Source: Kouyoumdjian JA, Yamamoto LA, Graca CR. Exploration of Intersections and Divergences of Long COVID and Chronic Fatigue Syndrome. Cureus. 2025 Aug 20;17(8):e90607. doi: 10.7759/cureus.90607. PMID: 40978825; PMCID: PMC12448662. https://pmc.ncbi.nlm.nih.gov/articles/PMC12448662/ (Full text)

Causes of symptoms and symptom persistence in long COVID and myalgic encephalomyelitis/chronic fatigue syndrome

Abstract:

Debilitating symptoms for many years can follow acute COVID-19 (“long COVID”), myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), and various post-acute infection syndromes (PAISs). Together, long COVID and ME/CFS affect 60-400 million individuals, globally. Many similar underlying biological abnormalities have been identified in both conditions including autoantibodies against neural targets, endothelial dysfunction, acquired mitochondrial dysfunction, and a pro-inflammatory gut microbiome. Each of these abnormalities may directly cause some of the symptoms.

In addition, the symptoms also may be caused by ancient, evolutionarily conserved symptomatic and metabolic responses to vital threats-sickness behavior and torpor-responses mediated by specific, recently discovered neural circuits. These neural circuits constitute a symptom-generating pathway, activated by neuroinflammation, which may be targeted by therapeutics to quell neuroinflammation.

Many factors cause the symptoms to become chronic, including persistent infectious agents (and/or their nucleic acids and antigens) and the fact that many of the underlying biological abnormalities reinforce each other, creating ongoing physiological vicious cycles.

Source:Komaroff AL, Dantzer R. Causes of symptoms and symptom persistence in long COVID and myalgic encephalomyelitis/chronic fatigue syndrome. Cell Rep Med. 2025 Jul 25:102259. doi: 10.1016/j.xcrm.2025.102259. Epub ahead of print. PMID: 40744021. https://www.cell.com/cell-reports-medicine/fulltext/S2666-3791(25)00332-5 (Full text)

Cytokine profiles associated with persisting symptoms of post-acute sequelae of COVID-19

Abstract:

Background/aims: Post-acute sequelae of COVID-19 (PASC) are highly heterogeneous; therefore, the pathophysiological mechanisms for PASC remain unclear. In this study, we aimed to examine the immunologic aspects of various PASC symptoms.

Methods: We prospectively enrolled adults aged ≥ 18 years who were diagnosed with COVID-19 between August 2022 and September 2023. Blood samples were collected from all participants, who were interviewed using a questionnaire for PASC symptoms at least once between 1 and 6 months after the COVID-19 diagnosis. For immunological evaluation, plasma concentrations of SARS-CoV-2 spike subunit 1-specific IgG and 33 cytokines were measured using enzyme-linked immunosorbent assays and multiplex-based immunoassay, respectively.

Results: In total, 156 pairs of blood samples and symptom reports from 79 participants were eligible for analysis. The most frequent symptom was fatigue, followed by post exertional malaise, chronic cough, thirst, and brain fog. Gastrointestinal symptoms, chest pain, post exertional malaise, smell/taste change, fatigue, brain fog, abnormal movement, and palpitation were accompanied by significant increases in IL-10, VEGF, and inflammatory cytokines like MIP-1α, IL-1β, IL-6, IL-8, MIG, granzyme A, and CX3CL1 levels, while chronic cough, dizziness, dyspnea, and hair loss were not accompanied by significant differences in cytokine levels.

Conclusion: Symptoms classified into different categories based on the dysfunctional organs may share a common pathophysiology regarding elevation of certain cytokines. Although PASC symptoms are heterogeneous, our findings suggest that T-cell recruitment, thrombosis, and increased vascular permeability might contribute to various symptom clusters sharing common pathophysiological mechanisms.

Source: Kwon JS, Chang E, Jang HM, Kim JY, Kim W, Son JY, Cha J, Jang CY, Bae S, Jung J, Kim MJ, Chong YP, Lee SO, Choi SH, Kim YS, Kim SH. Cytokine profiles associated with persisting symptoms of post-acute sequelae of COVID-19. Korean J Intern Med. 2025 Jul;40(4):667-675. doi: 10.3904/kjim.2024.217. Epub 2025 Jul 1. PMID: 40635493. https://kjim.org/journal/view.php?doi=10.3904/kjim.2024.217 (Full text)

Prevalence and severity of neurologic symptoms in Long-COVID and the role of pre-existing conditions, hospitalization, and mental health

Abstract:

Background: Long-COVID refers to ongoing, relapsing, or new symptoms present 30 or more days after Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection. This study examined the prevalence and severity of neurologic symptoms at greater than 1 month following acute SARS-CoV-2 infection and the influence of pre-existing neurologic and psychiatric conditions, current depression and anxiety status, and hospitalization on the presence and severity of these symptoms.

Methods: This prospective cohort study recruited primarily self-referred Long-COVID participants with confirmed SARS-CoV-2 infection. Online questionnaires inquiring about pre-existing conditions, neurologic symptoms and their severity pre, during and post COVID-19, and current anxiety and depression screening were completed by 213 participants at a median time of 8 months after infection. Descriptive analyses and prevalence modeling were performed.

Results: The most frequent neurologic symptoms post COVID-19 were fatigue, concentration/memory difficulties, unrefreshed sleep, and dysarthria/word finding difficulties (73.2–86.4%). Neurologic symptoms were highly prevalent with significantly greater odds post COVID-19 compared to pre for all symptoms and higher prevalence at time periods farther from infection, including those implicit in fibromyalgia and myalgic encephalomyelitis/chronic fatigue syndrome. Several severe neurologic symptoms were significantly more prevalent post COVID-19. Moderate to severe anxiety (34%) and depression (27%) were observed post COVID-19. Preexisting neurologic or psychiatric conditions did not demonstrate any significant difference in neurologic symptom prevalence post COVID-19. Those who met criteria for moderate or severe anxiety post COVID-19 had a significant difference in prevalence of fatigue, sensitivity to touch and unrefreshed sleep. Similarly, fatigue, concentration/memory difficulty and unrefreshed sleep were more prevalent in moderate to severe depression. There were no significant differences in neurologic symptom prevalence in a hospitalized group when compared to non- hospitalized.

Conclusion: Long-COVID has a high burden of long lasting and severe neurological sequelae. These sequelae are independent of pre-existing self-reported neurologic and psychiatric conditions, as well as previous hospitalization. Current moderate to severe anxiety and depression status can impact fatigue, cognition, and sleep post COVID-19. Focus on the biological impact of SARS-CoV-2 on the nervous system will be essential in ameliorating the tremendous symptom burden left in the wake of the COVID-19 pandemic.

Source: Huff Hanalise V. , Roberts Henry , Bartrum Elizabeth , Norato Gina , Grayson Nicholas , Fleig Katherine , Wilkerson Miciah J. , Stussman Barbara J. , Nath Avindra , Walitt Brian. Prevalence and severity of neurologic symptoms in Long-COVID and the role of pre-existing conditions, hospitalization, and mental health. Frontiers in Neurology, Volume 16 – 2025 https://www.frontiersin.org/journals/neurology/articles/10.3389/fneur.2025.1562084 10.3389/fneur.2025.1562084 ISSN:1664-2295 https://www.frontiersin.org/journals/neurology/articles/10.3389/fneur.2025.1562084/full (Full text)

Two Neurocognitive Domains Identified for Patients with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome and Post-Acute Sequelae of COVID-19

Abstract:

Patients with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) and Post-Acute Sequelae of COVID-19 (PASC) often have neurocognitive complaints that involve memory and concentration problems and difficulties paying attention. Other neurocognitive domains such as hypersensitivity to noise and light have rarely been included as aspects of neurocognitive impairment for these post-viral conditions.

The current study evaluated a more extensive list of neurocognitive items for a group of 2,313 patients with ME/CFS and 299 patients with PASC. Exploratory factor analyses found two factors for each patient group, one involving classic memory and concentration symptoms and the other involving sensory overload phenomena. The findings suggest that researchers might consider expanding the types of self-report neurocognitive symptoms among patients with these post-viral illnesses.

Source: Ariadna E Sandoval, Mingqi Li, Leonard A. Jason. Two Neurocognitive Domains Identified for Patients with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome and Post-Acute Sequelae of COVID-19. Front. Neurol., Sec. Cognitive and Behavioral Neurology, Volume 16 – 2025 | doi: 10.3389/fneur.2025.1612548 https://www.frontiersin.org/journals/neurology/articles/10.3389/fneur.2025.1612548/abstract

Long-term neurological and cognitive impact of COVID-19: a systematic review and meta-analysis in over 4 million patients

Abstract:

Background: Neuropsychiatric symptoms emerged early in the COVID-19 pandemic as a key feature of the virus, with research confirming a range of neuropsychiatric manifestations linked to acute SARS-CoV-2 infection. However, the persistence of neurological symptoms in the post-acute and chronic phases remains unclear. This meta-analysis assesses the long-term neurological effects of COVID-19 in recovered patients, providing insights for mental health service planning.

Methods: A comprehensive literature search was conducted across five electronic databases: PubMed, Scopus, Web of Science, EBSCO, and CENTRAL, up to March 22, 2024. Studies evaluating the prevalence of long-term neurological symptoms in COVID-19 survivors with at least six months of follow-up were included. Pooled prevalence estimates, subgroup analyses, and meta-regression were performed, and publication bias was assessed.

Results: The prevalence rates for the different symptoms were as follows: fatigue 43.3% (95% CI [36.1-50.9%]), memory disorders 27.8% (95% CI [20.1-37.1%]), cognitive impairment 27.1% (95% CI [20.4-34.9%]), sleep disorders 24.4% (95% CI [18.1-32.1%]), concentration impairment 23.8% (95% CI [17.2-31.9%]), headache 20.3% (95% CI [15-26.9%]), dizziness 16% (95% CI [9.5-25.7%]), stress 15.9% (95% CI [10.2-24%]), depression 14.0% (95% CI [10.1-19.2%]), anxiety 13.2% (95% CI [9.6-17.9%]), and migraine 13% (95% CI [2.2-49.8%]). Significant heterogeneity was observed across all symptoms. Meta-regression analysis showed higher stress, fatigue, and headache in females, and increased stress and concentration impairment with higher BMI.

Conclusions: Neurological symptoms are common and persistent in COVID-19 survivors. This meta-analysis highlights the significant burden these symptoms place on individuals, emphasizing the need for well-resourced multidisciplinary healthcare services to support post-COVID recovery.

Source: Elboraay T, Ebada MA, Elsayed M, Aboeldahab HA, Salamah HM, Rageh O, Elmallahy M, AboElfarh HE, Mansour LS, Nabil Y, Eltawab AKA, Atwan H, Alkanj S. Long-term neurological and cognitive impact of COVID-19: a systematic review and meta-analysis in over 4 million patients. BMC Neurol. 2025 Jun 14;25(1):250. doi: 10.1186/s12883-025-04174-9. PMID: 40514644; PMCID: PMC12166599. https://pmc.ncbi.nlm.nih.gov/articles/PMC12166599/ (Full text)

Mechanistic Insights Into Long Covid: Viral Persistence, Immune Dysregulation, and Multi-Organ Dysfunction

Abstract:

Long Covid is a post-viral syndrome characterized by persistent symptoms targeting multiple organ systems after initial SARS-CoV-2 infection. Current literature suggests that the mechanisms causing Long Covid involve viral persistence, immune dysregulation, systemic inflammation, endothelial dysfunction, and metabolic disturbances.

By forming reservoirs in the tissues of various organs, SARS-CoV-2 may evade immunological clearances while triggering immune responses and contributing to chronic symptoms through cytokine imbalances, T-cell exhaustion, and systemic inflammation. These symptoms parallel other post-viral syndromes such as Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS), suggesting similar mechanisms of pathology.

The coronavirus has also been linked to neuroinflammation and endothelial dysfunction causing cognitive symptoms and cardiovascular complications. Furthermore, its ability to lower energy production links it to post-exertion malaise (PEM) and muscle pain. These symptoms may result from iron dysregulation and persistent oxidative stress due to Covid-impaired mitochondrial function.

This review synthesizes current data on the mechanisms that drive Long Covid pathogenesis and explores potential therapeutic strategies to mitigate viral persistence, immune dysfunction, and metabolic disturbances. It is critical to understand these interactions to develop targeted interventions that address the long-term sequelae of SARS-CoV-2 infection and improve patient outcomes.

Source: Gupta G, Buonsenso D, Wood J, Mohandas S, Warburton D. Mechanistic Insights Into Long Covid: Viral Persistence, Immune Dysregulation, and Multi-Organ Dysfunction. Compr Physiol. 2025 Jun;15(3):e70019. doi: 10.1002/cph4.70019. PMID: 40474772. https://pubmed.ncbi.nlm.nih.gov/40474772/

Therapeutic Approaches to the Neurologic Manifestations of COVID-19

Abstract:

As of May 2022, there have been more than 527 million infections with severe acute respiratory disease coronavirus type 2 (SARS-CoV-2) and over 6.2 million deaths from Coronavirus Disease 2019 (COVID-19) worldwide. COVID-19 is a multisystem illness with important neurologic consequences that impact long-term morbidity and mortality.

In the acutely ill, the neurologic manifestations of COVID-19 can include distressing but relatively benign symptoms such as headache, myalgias, and anosmia; however, entities such as encephalopathy, stroke, seizures, encephalitis, and Guillain-Barre Syndrome can cause neurologic injury and resulting disability that persists long after the acute pulmonary illness. Furthermore, as many as one-third of patients may experience persistent neurologic symptoms as part of a Post-Acute Sequelae of SARS-CoV-2 infection (Neuro-PASC) syndrome.

This Neuro-PASC syndrome can affect patients who required hospitalization for COVID-19 or patients who did not require hospitalization and who may have had minor or no pulmonary symptoms. Given the large number of individuals affected and the ability of neurologic complications to impair quality of life and productivity, the neurologic manifestations of COVID-19 are likely to have major and long-lasting personal, public health, and economic consequences.

While knowledge of disease mechanisms and therapies acquired prior to the pandemic can inform us on how to manage patients with the neurologic manifestations of COVID-19, there is a critical need for improved understanding of specific COVID-19 disease mechanisms and development of therapies that target the neurologic morbidities of COVID-19. This current perspective reviews evidence for proposed disease mechanisms as they inform the neurologic management of COVID-19 in adult patients while also identifying areas in need of further research.

Source: Graham EL, Koralnik IJ, Liotta EM. Therapeutic Approaches to the Neurologic Manifestations of COVID-19. Neurotherapeutics. 2022 Sep;19(5):1435-1466. doi: 10.1007/s13311-022-01267-y. Epub 2022 Jul 21. PMID: 35861926; PMCID: PMC9302225. https://pmc.ncbi.nlm.nih.gov/articles/PMC9302225/ (Full text)