Persistent symptoms after COVID-19 in children and adolescents from Argentina

OBJECTIVES

Although long COVID-19 is widely recognized in adults, less information is available about this condition in children, especially in developing countries. Here, we studied the long-term symptoms of SARS-CoV-2 infection beyond 3 months and the associated risk factors in a pediatric population.

METHODS

This observational study included 639 Argentinian children and adolescents with previously confirmed COVID-19 from June 2020-June 2021 and 577 children without previous COVID-19. Parents completed a survey about symptoms that their child had for >3 months after the diagnosis of SARS-CoV-2 infection.

RESULTS

At least one persistent symptom was observed more frequently in children with previous COVID-19 than in the non-COVID-19 group (34% vs 13%, P <0.0001). SARS-CoV-2 infection increased the risk of headache, dizziness, loss of taste, dyspnea, cough, fatigue, muscle pain, and loss of weight by three- to seven-fold. The loss of smell was only reported in infected children. After controlling for the other variables, older age, symptomatic COVID-19, and comorbidities were independent predictors of long-term symptoms.

CONCLUSIONS

One-third of children experienced persistent symptoms after COVID-19. Older age, symptomatic infection, and comorbidities were shown to be risk factors for long COVID-19. Pediatric long COVID-19 is a new condition that requires further investigation.

Purinergic signaling pathway in severe COVID-19

Substantial efforts have been made to understand the immune response during severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, in order to identify and characterize risk factors, immune mechanisms responsible for the induction of tissue injury and potential therapeutic targets. Purinergic signaling pathway has shown to modulate the inflammatory processes in the course of several infectious diseases, but its role in the coronavirus disease 2019 (COVID-19) has not been clearly defined. Inflammation is usually associated to the release of ATP from different cell types, starting a cascade of events through the activation of a set of different purinergic receptors. This review summarizes the evidence showing the involvement of the purinergic system in the inflammatory condition that characterizes severe COVID-19.

Antibody response against SARS-CoV-2 variants of concern in children infected with pre-Omicron variants: An observational cohort study

Background

Despite that pediatric COVID-19 is usually asymptomatic or mild, SARS-CoV-2 infection typically results in the development of an antibody response. Contradictory observations have been reported when the antibody response of children and adults were compared in terms of strength, specificity and perdurability.

Methods

This observational study includes three cohorts infected with SARS-CoV-2 between March 2020-July 2021: unvaccinated infected children (n=115), unvaccinated infected adults (n=62), and vaccinated infected children (n=76). Plasma anti-spike IgG antibodies and neutralising activity against Wuhan, Delta and Omicron variants after 7-17 months post-infection were analysed.

Findings

More than 95% of unvaccinated infected children and adults remained seropositive when evaluated at 382-491 and 386-420 days after infection, respectively. Anti-spike IgG titers and plasma neutralising activity against Wuhan, Delta and Omicron variants were higher in children compared to adults. No differences were found when unvaccinated infected children were stratified by age, gender or presence/absence of symptoms in the acute phase of SARS-CoV-2 infection, but a slight decrease in the antibody response was observed in those with comorbidities. Vaccination of previously infected children with two doses of the inactivated BBIBP-CorV or the mRNA vaccines, BNT162b2 and/or mRNA-1273, further increased anti-spike IgG titers and neutralising activity against Wuhan, Delta and Omicron variants.

Interpretation

Unvaccinated infected children mount a more potent and sustained antibody response compared with adults, which is significantly increased after vaccination. Further studies including not only the analysis of the immune response but also the effectiveness to prevent reinfections by the different Omicron lineages are required to optimise vaccination strategy in children.

Funding

National Agency for Scientific and Technological Promotion from Argentina (PICTO-COVID-SECUELAS-00007 and PMO-BID-PICT2018-2548).

Extracellular ATP and Imbalance of CD4+ T Cell Compartment in Pediatric COVID-19

Severe COVID-19 in children is rare, but the reasons underlying are unclear. Profound alterations in T cell responses have been well characterized in the course of adult severe COVID-19, but little is known about the T cell function in children with COVID-19. Here, we made three major observations in a cohort of symptomatic children with acute COVID-19: 1) a reduced frequency of circulating FoxP3+ regulatory T cells, 2) the prevalence of a TH17 polarizing microenvironment characterized by high plasma levels of IL-6, IL-23, and IL17A, and an increased frequency of CD4+ T cells expressing ROR-γt, the master regulator of TH17 development, and 3) high plasma levels of ATP together with an increased expression of the P2X7 receptor. Moreover, that plasma levels of ATP displayed an inverse correlation with the frequency of regulatory T cells but a positive correlation with the frequency of CD4+ T cells positive for the expression of ROR-γt. Collectively, our data indicate an imbalance in CD4+ T cell profiles during pediatric COVID-19 that might favor the course of inflammatory processes. This finding also suggests a possible role for the extracellular ATP in the acquisition of an inflammatory signature by the T cell compartment offering a novel understanding of the involved mechanisms.

Cost-Effective Method to Perform SARS-CoV-2 Variant Surveillance: Detection of Alpha, Gamma, Lambda, Delta, Epsilon, and Zeta in Argentina

SARS-CoV-2 variants with concerning characteristics have emerged since the end of 2020. Surveillance of SARS-CoV-2 variants was performed on a total of 4,851 samples from the capital city and 10 provinces of Argentina, during 51 epidemiological weeks (EWs) that covered the end of the first wave and the ongoing second wave of the COVID-19 pandemic in the country (EW 44/2020 to EW 41/2021). The surveillance strategy was mainly based on Sanger sequencing of a Spike coding region that allows the identification of signature mutations associated with variants. In addition, whole-genome sequences were obtained from 637 samples. The main variants found were Gamma and Lambda, and to a lesser extent, Alpha, Zeta, and Epsilon, and more recently, Delta. Whereas, Gamma dominated in different regions of the country, both Gamma and Lambda prevailed in the most populated area, the metropolitan region of Buenos Aires. The lineages that circulated on the first wave were replaced by emergent variants in a term of a few weeks. At the end of the ongoing second wave, Delta began to be detected, replacing Gamma and Lambda. This scenario is consistent with the Latin American variant landscape, so far characterized by a concurrent increase in Delta circulation and a stabilization in the number of cases. The cost-effective surveillance protocol presented here allowed for a rapid response in a resource-limited setting, added information on the expansion of Lambda in South America, and contributed to the implementation of public health measures to control the disease spread in Argentina.

A poor and delayed anti-SARS-CoV2 IgG response is associated to severe COVID-19 in children

Background

Most children and youth develop mild or asymptomatic disease during severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. However, a very small number of patients suffer severe Coronavirus induced disease 2019 (COVID-19). The reasons underlying these different outcomes remain unknown.

Methods

We analyzed three different cohorts: children with acute infection (n=550), convalescent children (n=138), and MIS-C (multisystem inflammatory syndrome in children, n=42). IgG and IgM antibodies to the spike protein of SARS-CoV-2, serum-neutralizing activity, plasma cytokine levels, and the frequency of circulating Follicular T helper cells (cTfh) and plasmablasts were analyzed by conventional methods.

Findings

Fifty-eight percent of the children in the acute phase of infection had no detectable antibodies at the time of sampling while a seronegative status was found in 25% and 12% of convalescent and MIS-C children, respectively. When children in the acute phase of the infection were stratified according disease severity, we found that contrasting with the response of children with asymptomatic, mild and moderate disease, children with severe COVID-19 did not develop any detectable response. A defective antibody response was also observed in the convalescent cohort for children with severe disease at the time of admission. This poor antibody response was associated to both, a low frequency of cTfh and a high plasma concentration of inflammatory cytokines.

Interpretation

A weak and delayed kinetic of antibody response to SARS-CoV-2 together with a systemic pro-inflammatory profile characterize pediatric severe COVID-19. Because comorbidities are highly prevalent in children with severe COVID-19, further studies are needed to clarify their contribution in the weak antibody response observed in severe disease.

Funding

National Agency for Scientific and Technological Promotion from Argentina (IP-COVID-19-0277 and PMO-BID-PICT2018-2548).

Blood neutrophils from children with COVID-19 exhibit both inflammatory and anti-inflammatory markers

Background

Perhaps reflecting that children with COVID-19 rarely exhibit severe respiratory symptoms and often remain asymptomatic, little attention has been paid to explore the immune response in pediatric COVID-19. Here, we analyzed the phenotype and function of circulating neutrophils from children with COVID-19.

Methods

An observational study including 182 children with COVID-19, 21 children with multisystem inflammatory syndrome (MIS-C), and 40 healthy children was performed in Buenos Aires, Argentina. Neutrophil phenotype was analyzed by flow cytometry in blood samples. Cytokine production, plasma levels of IgG antibodies directed to the spike protein of SARS-CoV-2 and citrullinated histone H3 were measured by ELISA. Cell-free DNA was quantified by fluorometry.

Findings

Compared with healthy controls, neutrophils from children with COVID-19 showed a lower expression of CD11b, CD66b, and L-selectin but a higher expression of the activation markers HLA-DR, CD64 and PECAM-1 and the inhibitory receptors LAIR-1 and PD-L1. No differences in the production of cytokines and NETs were observed. Interestingly, the expression of CD64 in neutrophils and the serum concentration of IgG antibodies directed to the spike protein of SARS-CoV-2 distinguished asymptomatic from mild and moderate COVID-19.

Interpretation

Acute lung injury is a prominent feature of severe COVID-19 in adults. A low expression of adhesion molecules together with a high expression of inhibitory receptors in neutrophils from children with COVID-19 might prevent tissue infiltration by neutrophils preserving lung function.

Fcγ Receptor IIa (FCGR2A) Polymorphism Is Associated With Severe Respiratory Syncytial Virus Disease in Argentinian Infants

Background

Most patients with respiratory syncytial virus (RSV) infection requiring hospitalization have no risk factors for severe disease. Genetic variation in the receptor for the Fc portion of IgG (FcγR) determines their affinity for IgG subclasses driving innate and adaptive antiviral immunity. We investigated the relationship between FcγRIIa-H131R polymorphism and RSV disease.

Methods

Blood samples were collected from 182 infants ≤24-month-old (50 uninfected, 114 RSV-infected with moderate course and 18 suffering severe disease). FcγRIIa-H131R SNP genotypic frequencies (HH, HR, RR) and anti-RSV IgG1, IgG2 and IgG3 levels were studied.

Results

Genotypic frequencies for FcγRIIa-H131R SNP were comparable between uninfected and RSV-infected infants. In contrast, we found a significant higher frequency of HH genotype in severe RSV-infected children compared to moderate patients. Among severe group, HH infants presented more factors associated to severity than HR or RR patients did. Furthermore, compared to moderate RSV-infected infants, severe patients showed higher levels of anti-RSV IgG1 and IgG3.

Conclusions

We found an association between an FcγRIIa (H131) polymorphism and severe RSV disease, which points towards a critical role for interactions between FcγRs and immune complexes in RSV pathogenesis. This genetic factor could also predict the worse outcome and identify those infants at risk during hospitalization.

Impact of concomitant immunosuppression on the presentation and prognosis of patients with melanoma

9070

Background: Melanoma has been reported to be susceptible to immune control. Therefore, we hypothesized that concomitant immune suppression might impact the course of the disease. Methods: We examined the Beth Israel Deaconess Medical Center Cutaneous Oncology Program database for pts with immune suppression at the time of melanoma diagnosis. The demographics and stage of these pts were compared to those in the database as a whole. In addition, 3 controls matched for age, gender, stage and tumor location were identified for each case and disease outcome was compared between cases and controls. Results: 19 pts were identified with melanoma and concomitant immune suppression in a database of 1820 melanoma pts. Other diagnoses included renal transplant (4) inflammatory arthritis (8), Multiple Sclerosis (2), and ulcerative colitis (3). Immunosuppressive meds included methotrexate, azothioprine, cyclosporine, prednisone, infliximab, and natalizumab. Melanoma stages at diagnosis were in situ 1, IB 7, IIA 1, IIB 1, IIIB 3, IIIC 5, and IV 1. Compared to the database as a whole, cases were more likely to be female (84% vs 45%) and have a higher disease stage (42% stage IIIB/C vs 26%). In addition, more cases appeared to have an amelanotic primary (21% vs. 5.4%) or an atypical mole syndrome (21% vs 10.2%). For pts who relapsed, the cases had a shorter disease free interval (DFI) (2.1 vs 9.7 yrs) than the controls. At a median f/up of 52 mos, 37% of the cases had relapsed and all of these pts had died. At a median f/up of 76 mos, 30% of the controls had relapsed yet only 47% of these pts had died. As a consequence, cases appeared more likely to have died of their disease than controls (42% vs 23%) (p=0.10). Conclusions: Compared to the general melanoma population, pts with concomitant immune suppression appear more likely to be female, have an amelanotic primary or atypical mole syndrome and more advanced disease at presentation. Although pts with concomitant immune suppression are equally likely to relapse compared to matched controls, those that relapse appear to have a shorter DFI and to be less likely to be salvaged, suggesting more aggressive tumor behavior in this setting. Thus, diagnosis and treatment of a primary melanoma at an early stage appears especially important in an immunosuppressed population.

No significant financial relationships to disclose.

A phase II pilot trial of low dose, continuous infusion, or “metronomic”, paclitaxel and oral celecoxib in patients with metastatic melanoma

8010

Background: In patients (pts) with metastatic melanoma (MM), tumor angiogenesis has been associated with tumor progression and survival (Ugurel et al, JCO 19:577). Microtubule and cyclooxygenase (COX)-2 inhibitors, both alone and in combination, have been shown to have inhibitory effects on endothelial cells and tumor angiogenesis both in vitro and in vivo (Merchan et al, Int J Ca 113:490. Jones et al, Nat Med 5:1418). We tested the safety and efficacy of a regimen involving low dose, continuous infusion (CIV) paclitaxel and oral celecoxib in pts with MM. Methods: Pts received paclitaxel 10mg/m2 for 96 hours weekly by CIV and Celecoxib 400 mg po/bid. Systemic tumor response was assessed at 6 wk intervals (1 cycle (C)). Pts without unacceptable toxicity or clinically significant disease progression (PD) received additional cycles. Pts exhibiting PD after C 2 relative to end of C 1 were removed from study. Pts on anticoagulants, with recent MI or untreated brain metastases were ineligible. Results: 20 pts (12 M/ 8 F), median age 55 (range 44–65), ECOG PS 0/1/2 (5/13/2), M1a/M1b/M1c: 1/1/18 (90%), and prior systemic therapy regimens 0/1/2/3+: 1/7/5/7 were enrolled in the protocol. Sites of systemic disease included: lung (13 pts), LN (14), soft tissue (13), liver (9), bone (4), brain (6), other (11). 3 pts came of study prior to treatment with rapid disease progression. Treatment related grade 3–4 toxicities included line related (LR) bacteremia (3 pts), LR DVT (3 pts), LR PE (3). There were no grade 3–4 toxicities attributed to paclitaxel or celecoxib. No pt exhibited a major tumor response; 6/20 (30%) pts had stable disease for 17, 18, 18, 18+, 30+, 60 wks. Median TTP was 6 wks (range 3- 60); median overall survival was 6 months (range 1–29). Conclusions: Low-dose, CIV paclitaxel and oral celecoxib leads to disease stabilization in a significant portion of previously treated pts with MM. This suggests a role for combination anti-angiogenic therapy in MM. The incidence of LR toxicities indicates that alternative microtubule inhibitors, such as oral taxanes, should be considered in combination with COX-2 inhibitors for future studies. Results of biomarker studies will be presented at the meeting. Supported by Pfizer Inc. and NIH R21 CA097730.

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