ImportanceSARS-CoV-2 infection is associated with persistent, relapsing, or new symptoms or other health effects occurring after acute infection, termed postacute sequelae of SARS-CoV-2 infection (PASC), also known as long COVID. Characterizing PASC requires analysis of prospectively and uniformly collected data from diverse uninfected and infected individuals.ObjectiveTo develop a definition of PASC using self-reported symptoms and describe PASC frequencies across cohorts, vaccination status, and number of infections.Design, Setting, and ParticipantsProspective observational cohort study of adults with and without SARS-CoV-2 infection at 85 enrolling sites (hospitals, health centers, community organizations) located in 33 states plus Washington, DC, and Puerto Rico. Participants who were enrolled in the RECOVER adult cohort before April 10, 2023, completed a symptom survey 6 months or more after acute symptom onset or test date. Selection included population-based, volunteer, and convenience sampling.ExposureSARS-CoV-2 infection.Main Outcomes and MeasuresPASC and 44 participant-reported symptoms (with severity thresholds).ResultsA total of 9764 participants (89% SARS-CoV-2 infected; 71% female; 16% Hispanic/Latino; 15% non-Hispanic Black; median age, 47 years [IQR, 35-60]) met selection criteria. Adjusted odds ratios were 1.5 or greater (infected vs uninfected participants) for 37 symptoms. Symptoms contributing to PASC score included postexertional malaise, fatigue, brain fog, dizziness, gastrointestinal symptoms, palpitations, changes in sexual desire or capacity, loss of or change in smell or taste, thirst, chronic cough, chest pain, and abnormal movements. Among 2231 participants first infected on or after December 1, 2021, and enrolled within 30 days of infection, 224 (10% [95% CI, 8.8%-11%]) were PASC positive at 6 months.Conclusions and RelevanceA definition of PASC was developed based on symptoms in a prospective cohort study. As a first step to providing a framework for other investigations, iterative refinement that further incorporates other clinical features is needed to support actionable definitions of PASC.

The postacute sequelae of SARS-CoV-2 infection (PASC) has emerged as a long-term complication in adults, but current understanding of the clinical presentation of PASC in children is limited.OBJECTIVE To identify diagnosed symptoms, diagnosed health conditions, and medications associated with PASC in children. DESIGN, SETTING AND PARTICIPANTSThis retrospective cohort study used electronic health records from 9 US children's hospitals for individuals younger than 21 years who underwent antigen or reverse transcriptase-polymerase chain reaction (RT-PCR) testing for SARS-CoV-2 between March 1, 2020, and October 31, 2021, and had at least 1 encounter in the 3 years before testing. EXPOSURES SARS-CoV-2 positivity by viral test (antigen or RT-PCR).MAIN OUTCOMES AND MEASURES Syndromic (symptoms), systemic (conditions), and medication PASC features were identified in the 28 to 179 days following the initial test date. Adjusted hazard ratios (aHRs) were obtained for 151 clinically predicted PASC features by contrasting viral test-positive groups with viral test-negative groups using proportional hazards models, adjusting for site, age, sex, testing location, race and ethnicity, and time period of cohort entrance. The incidence proportion for any syndromic, systemic, or medication PASC feature was estimated in the 2 groups to obtain a burden of PASC estimate. RESULTS Among 659 286 children in the study sample, 348 091 (52.8%) were male, and the mean (SD) age was 8.1 (5.7) years. A total of 59 893 (9.1%) tested positive by viral test for SARS-CoV-2, and 599 393 (90.9%) tested negative. Most were tested in outpatient testing facility settings (322 813 [50.3%]) or office settings (162 138 [24.6%]). The most common syndromic, systemic, and medication features were loss of taste or smell (aHR, 1.96; 95% CI, myocarditis (aHR, 3.10; 95% CI,, and cough and cold preparations (aHR, 1.52; 95% CI, 1.18-1.96), respectively. The incidence of at least 1 systemic, syndromic, or medication feature of PASC was 41.9% (95% CI, 41.4-42.4) among viral test-positive children vs 38.2% (95% CI,) among viral test-negative children, with an incidence proportion difference of 3.7% (95% CI, 3.2-4.2). A higher strength of association for PASC was identified in those cared for in the intensive care unit during the acute illness phase, children younger than 5 years, and individuals with complex chronic conditions. CONCLUSIONS AND RELEVANCEIn this large-scale, exploratory study, the burden of pediatric PASC that presented to health systems was low. Myocarditis was the most commonly diagnosed PASC-associated condition. Acute illness severity, young age, and comorbid complex chronic disease increased the risk of PASC.

Importance: The post-acute sequelae of SARS-CoV-2 (PASC) has emerged as a long-term complication in adults, but current understanding of the clinical presentation of PASC in children is limited. Objective: To identify diagnosed symptoms, diagnosed health conditions and medications associated with PASC in children. Design, Setting and Participants: Retrospective cohort study using electronic health records from 9 US children's hospitals for individuals <21 years-old who underwent reverse transcriptase polymerase chain reaction (RT-PCR) testing for SARS-CoV-2 between March 1, 2020 to October 31, 2021 and had at least 1 encounter in the 3 years before testing. Exposure: SARS-CoV-2 PCR positivity. Main Outcomes and Measures: We identified syndromic (symptoms), systemic (conditions), and medication PASC features in the 28-179 days following the initial test date. Adjusted hazard ratios (aHRs) were obtained for 151 clinically predicted PASC features by contrasting PCR-positive with PCR-negative groups using proportional hazards models, adjusting for site, age, sex, testing location, race/ethnicity, and time-period of cohort entrance. We estimated the incidence proportion for any syndromic, systemic or medication PASC feature in the two groups to obtain a burden of PASC estimate. Results: Among 659,286 children in the study sample, 59,893 (9.1%) tested positive by PCR for SARS-CoV-2. Most were tested in outpatient testing facility (50.3%) or office (24.6%) settings. The most common syndromic, systemic, and medication features were loss of taste or smell (aHR 1.96 [95% CI 1.16-3.32), myocarditis (aHR 3.10 [95% CI 1.94-4.96]), and cough and cold preparations (aHR 1.52 [95% CI 1.18-1.96]). The incidence of at least one systemic/syndromic/medication feature of PASC was 41.9% among PCR-positive children versus 38.2% among PCR-negative children, with an incidence proportion difference of 3.7% (95% CI 3.2-4.2%). A higher strength of association for PASC was identified in those cared for in the ICU during the acute illness phase, children less than 5 years-old, and individuals with complex chronic conditions. Conclusions and Relevance: In this large-scale, exploratory study, the burden of pediatric PASC that presented to health systems was low. Myocarditis was the most commonly diagnosed PASC-associated condition. Acute illness severity, young age, and comorbid complex chronic disease increased the risk of PASC.

We completely compute the Real Johnson-Wilson cohomology of CP ∞ . Applying techniques from equivariant stable homotopy theory to the Bockstein spectral sequence, we produce permanent cycles and solve extension problems to give an explicit description of the ring ER(n) * (CP ∞ ).where x(n) ∈ ER(n) −λ(n) is (2 n+1 −1)-nilpotent and λ(n) = 2(2 n −1) 2 −1 = 2 2n+1 −2 n+2 +1. This was constructed in [KW07] and leads to a Bockstein spectral sequence of the formOur main result is a computation of ER(n) * (CP ∞ ) for all n. ER(n) is not a complex oriented theory, and so the computation is nontrivial. The Atiyah-Hirzebruch spectral sequence is unwieldy, so we use the above Bockstein spectral sequence instead. Even this has nontrivial higher differentials, but what makes ER(n) * (CP ∞ ) computable is the fact that, after some rearranging, the only interesting differential is d 1 and the higher differentials all play out in the coefficients. We develop methods of producing permanent cycles and obtain control over the extension problems in the Bockstein spectral sequence to produce a complete description of the ring ER(n) * (CP ∞ ).In the case of ER (1) = KO (2) , this problem has a long history. KO * (CP ∞ ) was first computed in degree zero by Sanderson [San64], then in all degrees with ring structure on KO even (CP ∞ ) by Fujii [Fuj67]. Yamaguchi [Yam07] gave the first complete description of KO * (CP ∞ ) as a ring. All three computations use the Atiyah-Hirzebruch spectral sequence. Bruner and Greenlees [BG10] computed the connective real K-theory of CP ∞ using the Bockstein spectral sequence. Our result gives the ER(n)-cohomology of CP ∞ for all n in the same level of detail as Yamaguchi's description and reproduces n = 1 as a nearly degenerate case (see Remarks 1. 4 and 10.9). The answer for n > 1 is richer in the sense that it yields a great deal more 2-torsion.This paper forms part of a program to compute the ER(n)-cohomology of basic spaces. The spaces whose ER(n)-cohomology is known at present may be divided into two families. Building on the computations in [KW08a, KW08b, KW14], the results of [KLW16a] identify a class of spaces whose ER(n)-cohomology is directly computed from E(n)cohomology (which is known) by base change. These include BO(q) for q ≤ ∞, the connective covers BSO, BSpin and BString (the last for n ≤ 2 only), and half of all Eilenberg MacLane spaces-those of the form K(Z, 2k + 1) and K(Z/2 q , 2k). The space of interest in this paper, CP ∞ = K(Z, 2), does not belong to this family and is the first space of 'exotic type' whose ER(n)-cohomology is nevertheless computable. Our computations here open the door to the results of [KLW16c], which deal with the ER(2)-cohomology of BZ/2 q and truncated complex projective spaces CP k . The computation of ER(n) * (CP ∞ ) also points the way toward the ER(n)-cohomology of the spaces j i=1 CP ∞ , BU(q) and its connective covers, and the other half of the Eilenberg MacLane spaces.One motivation for developing ER(n) (and ER(2) in particular) as a computable theory...

Structured Abstract Objectives Post-acute sequalae of SARS-CoV-2 infection (PASC) is not well defined in pediatrics given its heterogeneity of presentation and severity in this population. The aim of this study is to use novel methods that rely on data mining approaches rather than clinical experience to detect conditions and symptoms associated with pediatric PASC. Materials and Methods We used a propensity-matched cohort design comparing children identified using the new PASC ICD10CM diagnosis code (U09.9) (N = 1309) to children with (N = 6545) and without (N = 6545) SARS-CoV-2 infection. We used a tree-based scan statistic to identify potential condition clusters co-occurring more frequently in cases than controls. Results We found significant enrichment among children with PASC in cardiac, respiratory, neurologic, psychological, endocrine, gastrointestinal, and musculoskeletal systems, the most significant related to circulatory and respiratory such as dyspnea, difficulty breathing, and fatigue and malaise. Discussion Our study addresses methodological limitations of prior studies that rely on pre-specified clusters of potential PASC-associated diagnoses driven by clinician experience. Future studies are needed to identify patterns of diagnoses and their associations to derive clinical phenotypes. Conclusion We identified multiple conditions and body systems associated with pediatric PASC. Because we rely on a data-driven approach, several new or under-reported conditions and symptoms were detected that warrant further investigation. Lay Summary Pediatric long COVID in children does not currently have a precise clinical definition, in part due to its widely varying presentation in kids. By comparing children diagnosed with long COVID to children who had COVID-19 but were not diagnosed with long COVID, this study identified several groups of symptoms and conditions that are associated with pediatric long COVID. These findings can be used towards developing a precise definition of long COVID in children for use in future studies.