Comparison of Symptoms Associated With SARS-CoV-2 Variants Among Children in Canada

No Association between SARS-CoV-2 Infection and Quality of Life 6- and 12-Months After Infection

OBJECTIVE

To assess the association between SARS-CoV-2 infection and long-term quality of life (QoL).

METHODS

Prospective cohort study with 6- and 12-month follow-up conducted in 14 Canadian institutions. Children tested for SARS-CoV-2 between August 2020 and February 2022 were eligible. QoL was measured using PedsQLTM-4.0, overall health status scores 6- and 12-months after testing.

RESULTS

Among SARS-CoV-2 positive and negative participants eligible for long-term follow-up, 74.8% (505/675) and 71.8% (1106/1541) at 6- and 59.0% (727/1233) and 68.1% (2520/3699) at 12-months, completed follow-up, respectively. Mean ± SD PedsQL™ scores did not differ between positive and negative groups; difference: -0.86 (95%CI: -2.33, 0.61) at 6- and -0.48 (95%CI: -1.6, 0.64) at 12-months, respectively. SARS-CoV-2 test-positivity was associated with higher social subscale scores. Although in bivariate analysis, overall health status at 6-month was higher among SARS-CoV-2 cases [difference: 2.16 (95%CI: 0.80, 3.53)], after adjustment for co-variates, SARS-CoV-2 infection was not independently associated with total PedsQL™ or overall health status at either time point. Parental perception of recovery did not differ based on SARS-CoV-2 test-status at either time point.

CONCLUSIONS

SARS-CoV-2 infection was not associated with QoL, overall health status, or parental perception of recovery 6- and 12-months following infection.

CLINICAL TRIAL REGISTRATION (IF ANY)

N/A.

Clinical manifestations and long-term symptoms associated with SARS-CoV-2 omicron infection in children aged 0-17 years in Beijing: a single-center study

Objective

The study aims to analyze the clinical characteristics of acute phase of SARS-CoV-2 infection in children aged 0-17 years with the Omicron variant, and summarize the persistent symptoms or new-onset clinical manifestations from 4 to 12 weeks after acute COVID. Explore the association between the vaccination status and SARS-CoV-2 neutralizing antibody levels post infection among preschool-aged children. The comprehensive study systematically describes the clinical characteristics of children infected with SARS-CoV-2, providing a foundation for diagnosis and evaluating long-term COVID in pediatric populations.

Methods

The study enrolled children who were referred to the Children's Hospital, Capital Institute of Pediatrics, (Beijing, China) from January 10, 2023 to March 31, 2023. Participants were classified as infant and toddlers, preschool, school-age, and adolescent groups. Children or their legal guardians completed survey questionnaires to provide information of previous SARS-CoV-2 infection history, as well as clinical presentation during the acute phase and long-term symptoms from 4 to 12 weeks following infection. Furthermore, serum samples were collected from children with confirmed history of SARS-CoV-2 infection for serological testing of neutralizing antibodies.

Results

The study recruited a total of 2,001 children aged 0-17 years who had previously tested positive for SARS-CoV-2 through nucleic acid or antigen testing. Fever emerged as the predominant clinical manifestation in 1,902 (95.1%) individuals with body temperature ranging from 37.3 to 40.0°C. Respiratory symptoms were identified as secondary clinical manifestations, with cough being the most common symptom in 777 (38.8%) children, followed by sore throat (22.1%), nasal congestion (17.8%), and runnning nose (17.2%). Fatigue (21.6%), headache (19.8%) and muscle-joint pain (13.5%) were frequently reported systemic symptoms in children. The proportion of children with symptoms of SARS-CoV-2 infection varied across age groups. 1,100 (55.0%) children experienced persistent symptoms from 4 to 12 weeks post the acute phase of infection. Trouble concentrating (22.1%), cough (22.1%), and fatigue (12.1%) were frequently reported across age groups in the extended period. A limited number of children exhibited cardiovascular symptoms with chest tightness, tachycardia, and chest pain reported by 3.5%, 2.5%, and 1.8% of children, respectively. Among 472 children aged 3-5 years, 208 children had received two doses of SARS-CoV-2 vaccine at least 6 months prior to infection, and no association was found between the incidence of long-term COVID and pre-infection vaccination statuses among the 3-5 years age groups (χ2 = 1.136, P = 0.286).

Conclusions

In children aged 0-17 years infected with SARS-CoV-2 Omicron variant, fever was the primary clinical manifestation in the acute phase, followed by respiratory symptoms, systemic non-specific and digestive presentations. In particular, respiratory and digestive system symptoms were more frequent in children aged above 6 years. Regarding the long-term symptoms from 4 to 12 weeks post-infection, the most common presentations were concentrating difficulty, cough, and fatigue. The incidence of persistent symptoms of SARS-CoV-2 did not exhibit a significant correlation with vaccination status, which was attributed to the waning efficacy of the vaccine-induced humoral immune response after 6 months.

Neurological manifestations and risk factors associated with poor prognosis in hospitalized children with Omicron variant infection

There are increasing reports of neurological manifestation in children with coronavirus disease 2019 (COVID-19). However, the frequency and clinical outcomes of in hospitalized children infected with the Omicron variant are unknown. The aim of this study was to describe the clinical characteristics, neurological manifestations, and risk factor associated with poor prognosis of hospitalized children suffering from COVID-19 due to the Omicron variant. Participants included children older than 28 days and younger than 18 years. Patients were recruited from December 10, 2022 through January 5, 2023. They were followed up for 30 days. A total of 509 pediatric patients hospitalized with the Omicron variant infection were recruited into the study. Among them, 167 (32.81%) patients had neurological manifestations. The most common manifestations were febrile convulsions (n = 90, 53.89%), viral encephalitis (n = 34, 20.36%), epilepsy (n = 23, 13.77%), hypoxic-ischemic encephalopathy (n = 9, 5.39%), and acute necrotizing encephalopathy (n = 6, 3.59%). At discharge, 92.81% of patients had a good prognosis according to the Glasgow Outcome Scale (scores ≥ 4). However, 7.19% had a poor prognosis. Eight patients died during the follow-up period with a cumulative 30-day mortality rate of 4.8% (95% confidence interval (CI) 1.5-8.1). Multivariate analysis revealed that albumin (odds ratio 0.711, 95% CI 0.556-0.910) and creatine kinase MB (CK-MB) levels (odds ratio 1.033, 95% CI 1.004-1.063) were independent risk factors of poor prognosis due to neurological manifestations. The area under the curve for the prediction of poor prognosis with albumin and CK-MB was 0.915 (95%CI 0.799-1.000), indicating that these factors can accurately predict a poor prognosis.          Conclusion: In this study, 32.8% of hospitalized children suffering from COVID-19 due to the Omicron variant infection experienced neurological manifestations. Baseline albumin and CK-MB levels could accurately predict poor prognosis in this patient population. What is Known: • Neurological injury has been reported in SARS-CoV-2 infection; compared with other strains, the Omicron strain is more likely to cause neurological manifestations in adults. • Neurologic injury in adults such as cerebral hemorrhage and epilepsy has been reported in patients with Omicron variant infection. What is New: • One-third hospitalized children with Omicron infection experience neurological manifestations, including central nervous system manifestations and peripheral nervous system manifestations. • Albumin and CK-MB combined can accurately predict poor prognosis (AUC 0.915), and the 30-day mortality rate of children with Omicron variant infection and neurological manifestations was 4.8%.

Moving Biosurveillance Beyond Coded Data Using AI for Symptom Detection From Physician Notes: Retrospective Cohort Study

BACKGROUND

Real-time surveillance of emerging infectious diseases necessitates a dynamically evolving, computable case definition, which frequently incorporates symptom-related criteria. For symptom detection, both population health monitoring platforms and research initiatives primarily depend on structured data extracted from electronic health records.

OBJECTIVE

This study sought to validate and test an artificial intelligence (AI)-based natural language processing (NLP) pipeline for detecting COVID-19 symptoms from physician notes in pediatric patients. We specifically study patients presenting to the emergency department (ED) who can be sentinel cases in an outbreak.

METHODS

Subjects in this retrospective cohort study are patients who are 21 years of age and younger, who presented to a pediatric ED at a large academic children's hospital between March 1, 2020, and May 31, 2022. The ED notes for all patients were processed with an NLP pipeline tuned to detect the mention of 11 COVID-19 symptoms based on Centers for Disease Control and Prevention (CDC) criteria. For a gold standard, 3 subject matter experts labeled 226 ED notes and had strong agreement (F1-score=0.986; positive predictive value [PPV]=0.972; and sensitivity=1.0). F1-score, PPV, and sensitivity were used to compare the performance of both NLP and the International Classification of Diseases, 10th Revision (ICD-10) coding to the gold standard chart review. As a formative use case, variations in symptom patterns were measured across SARS-CoV-2 variant eras.

RESULTS

There were 85,678 ED encounters during the study period, including 4% (n=3420) with patients with COVID-19. NLP was more accurate at identifying encounters with patients that had any of the COVID-19 symptoms (F1-score=0.796) than ICD-10 codes (F1-score =0.451). NLP accuracy was higher for positive symptoms (sensitivity=0.930) than ICD-10 (sensitivity=0.300). However, ICD-10 accuracy was higher for negative symptoms (specificity=0.994) than NLP (specificity=0.917). Congestion or runny nose showed the highest accuracy difference (NLP: F1-score=0.828 and ICD-10: F1-score=0.042). For encounters with patients with COVID-19, prevalence estimates of each NLP symptom differed across variant eras. Patients with COVID-19 were more likely to have each NLP symptom detected than patients without this disease. Effect sizes (odds ratios) varied across pandemic eras.

CONCLUSIONS

This study establishes the value of AI-based NLP as a highly effective tool for real-time COVID-19 symptom detection in pediatric patients, outperforming traditional ICD-10 methods. It also reveals the evolving nature of symptom prevalence across different virus variants, underscoring the need for dynamic, technology-driven approaches in infectious disease surveillance.

Presentations and Outcomes Among Infants ≤90 Days With and Without SARS-CoV-2

OBJECTIVES

To compare symptoms and outcomes among infants aged ≤90 days tested for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in a broad, international sample of emergency departments (EDs).

METHODS

This was a secondary analysis of infants aged 0 to 90 days with suspected SARS-CoV-2 infections tested using molecular approaches and with 14-day follow-up. The parent studies were conducted at 41 EDs in 10 countries (the global Pediatric Emergency Research Network; March 2020-June 2021) and 14 EDs across Canada (Pediatric Emergency Research Canada network; August 2020-February 2022). Symptom profiles included presence and number of presenting symptoms. Clinical outcomes included hospitalization, ICU admission, and severe outcomes (a composite of intensive interventions, severe organ impairment, or death).

RESULTS

Among 1048 infants tested for SARS-CoV-2, 1007 (96.1%) were symptomatic at presentation and 432 (41.2%) were SARS-CoV-2-positive. A systemic symptom (any of the following: Apnea, drowsiness, irritability, or lethargy) was most common and present in 646 (61.6%) infants, regardless of SARS-CoV-2 status. Although fever and upper respiratory symptoms were more common among SARS-CoV-2-positive infants, dehydration, gastrointestinal, skin, and oral symptoms, and the overall number of presenting symptoms did not differ between groups. Infants with SARS-CoV-2 infections were less likely to be hospitalized (32.9% vs 44.8%; difference -11.9% [95% confidence interval (CI) -17.9% to -6.0%]), require intensive care (1.4% vs 5.0%; difference -3.6% [95% CI -5.7% to -1.6%]), and experience severe outcomes (1.4% vs 5.4%; difference -4.0% [95% CI -6.1% to -1.9%]).

CONCLUSIONS

SARS-CoV-2 infections may be difficult to differentiate from similar illnesses among the youngest infants but are generally milder. SARS-CoV-2 testing can help inform clinical management.

The changing clinical presentation of COVID-19 in children during the course of the pandemic

AIM

To investigate the evolution of clinical symptoms of COVID-19 in children throughout the pandemic.

METHODS

In this national prospective surveillance study, symptoms in children hospitalised with COVID-19 were collected from all paediatric hospitals in Switzerland between March 2020 and March 2023. Data was analysed across four time periods, according to the predominantly circulating SARS-CoV-2 variant: T1 (wild-type), T2 (Alpha), T3 (Delta) and T4 (Omicron), as well as by age group.

RESULTS

The study included 1323 children. The proportion of children admitted to an intensive care unit remained stable throughout the pandemic. However, the pattern and frequency of clinical manifestations changed over time. Respiratory symptoms were less prevalent during T1 (wild-type), fever during T2 (Alpha) and rash during T4 (Omicron). In contrast, fever and neurological symptoms were more prevalent during T4 (Omicron). Newly described symptoms during T4 (Omicron) included conjunctivitis, laryngotracheitis and seizures. Fever was more prevalent among neonates and infants whereas respiratory symptoms were more common among infants. Gastrointestinal symptoms were more frequent among toddlers, while both toddlers and school-aged children presented with neurological symptoms more often than other age groups.

CONCLUSION

Continuous surveillance is required to detect changes in manifestations and there by be prepared for the optimal management of complications in children with COVID-19.

Comparing COVID-19 severity in patients hospitalized for community-associated Delta, BA.1 and BA.4/5 variant infection

Background

Despite decreasing COVID-19 disease severity during the Omicron waves, a proportion of patients still require hospitalization and intensive care.

Objective

To compare demographic characteristics, comorbidities, vaccination status, and previous infections in patients hospitalized for community-associated COVID-19 (CAC) in predominantly Delta, Omicron BA.1 and BA.4/5 SARS-CoV-2 waves.

Methods

Data were extracted from three national databases-the National COVID-19 Database, National Vaccination Registry and National Registry of Hospitalizations.

Results

Among the hospitalized CAC patients analyzed in this study, 5,512 were infected with Delta, 1,120 with Omicron BA.1, and 1,143 with the Omicron BA.4/5 variant. The age and sex structure changed from Delta to BA.4/5, with the proportion of women (9.5% increase), children and adolescents (10.4% increase), and octa- and nonagenarians increasing significantly (24.5% increase). Significantly more patients had comorbidities (measured by the Charlson Comorbidity Index), 30.3% in Delta and 43% in BA.4/5 period. The need for non-invasive ventilatory support (NiVS), ICU admission, mechanical ventilation (MV), and in-hospital mortality (IHM) decreased from Delta to Omicron BA.4/5 period for 12.6, 13.5, 11.5, and 6.3%, respectively. Multivariate analysis revealed significantly lower odds for ICU admission (OR 0.68, CI 0.54-0.84, p < 0.001) and IHM (OR 0.74, CI 0.58-0.93, p = 0.011) during the Delta period in patients who had been fully vaccinated or boosted with a COVID-19 vaccine within the previous 6 months. In the BA.1 variant period, patients who had less than 6 months elapsed between the last vaccine dose and SARS-CoV-2 positivity had lower odds for MV (OR 0.38, CI 0.18-0.72, p = 0.005) and IHM (OR 0.56, CI 0.37- 0.83, p = 0.005), but not for NIVS or ICU admission.

Conclusion

The likelihood of developing severe CAC in hospitalized patients was higher in those with the Delta and Omicron BA.1 variant compared to BA.4/5.

Vaccine Effectiveness against SARS-CoV-2 Infection during the Circulation of Alpha, Delta, or Omicron Variants: A Retrospective Cohort Study in a Tertiary Hospital in Serbia

The COVID-19 pandemic prompted rapid vaccine development and deployment worldwide. Despite widespread vaccination efforts, understanding the effectiveness of vaccines in hospitalized patients remains a critical concern. This retrospective cohort study, conducted at a tertiary healthcare centre in Serbia, tracked patients hospitalized during different waves of COVID-19 variants-Alpha, Delta, and Omicron. Data collection included demographics, comorbidities, symptoms, and vaccination status. Among 3593 patients, those with prior exposure to COVID-19 cases or hospital treatment showed higher positivity rates. Symptom prevalence varied across waves, with coughs persisting. Patients without chronic diseases were more frequent among those testing negative. Vaccine effectiveness varied, with Sinopharm demonstrating a 45.6% effectiveness initially and Pfizer-BioNTech showing an effectiveness of up to 74.8% within 0-84 days after the second dose. Mixed-dose strategies, notably Sinopharm as a primary dose followed by a Pfizer-BioNTech booster, suggested increased protection. Despite substantial vaccination availability, a significant portion of hospitalized patients remained unvaccinated. This study underscores the dynamic nature of vaccine effectiveness and advocates for booster strategies to address evolving challenges in combating COVID-19, particularly in hospitalized patients.

Employee investigation and contact tracing program in a pediatric cancer hospital to mitigate the spread of COVID-19 among the workforce, patients, and caregivers

Background

Case investigations and contact tracing are essential disease control measures used by health departments. Early in the pandemic, they were seen as a key strategy to stop COVID-19 spread. The CDC urged rapid action to scale up and train a large workforce and collaborate across public and private agencies to halt COVID-19 transmission.

Methods

We developed a program for case investigation and contact tracing that followed CDC and local health guidelines, compliant with the Occupational Safety and Health Administration (OSHA) regulations and tailored to the needs and resources of our institution. Program staff were trained and assessed for competency before joining the program.

Results

From March 2020 to May 2021, we performed 838 COVID-19 case investigations, which led to 136 contacts. Most employees reported a known SARS-CoV-2 exposure from the community (n = 435) or household (n = 343). Only seven (5.1%) employees were determined as more likely than not to have SARS-CoV-2 infection related to workplace exposure, and when so, lapses in following the masking recommendations were identified. Between June 2021-February 2022, our program adjusted to the demand of the different waves, particularly omicron, by significantly reducing the amount of data collected. No transmission from employees to patients or caregivers was observed during this period.

Conclusion

Prompt implementation of case investigation and contact tracing is possible, and it effectively reduces workplace exposures. This approach can be adapted to suit the specific needs and requirements of various healthcare settings, particularly those serving the most vulnerable patient populations.

Characteristics and Presentations of Hospitalized Children Due to 3 Predominate COVID-19 Variants Within a Health Care Network

Objective of this article is to describe differences in the demographic and clinical characteristics, severity of illness, and outcomes in pediatric patients with different SARS-CoV-2 variants. We conducted a retrospective study of pediatric patients admitted with COVID-19 during the 3 large waves of infection within a health network in New Jersey. We included demographic characteristics, clinical features, and outcomes and compared the data with respect to the different variants. Of 351 total patients included in this study, 74 were admitted during wave 1, 94 during wave 2, and 181 during wave 3. The median age of patients decreased from wave 1 (11.5 years) to wave 3 (3 years) (P = .0034). 87.7% of the patients were unvaccinated. The overall incidence of admissions due to pneumonia related to COVID-19 decreased in wave 3. COVID-19 bronchiolitis or croup admissions occurred mostly in wave 3. There was no significant difference in the number of patients requiring intensive care in any particular wave. Length of stay decreased across the waves (P < .0001). Treatments required did not vary between the waves except for a decrease in antibiotic use with each subsequent wave (P < .0001). The impact of COVID-19 on the pediatric population differs from the adult population, and the overall number of hospitalized children has mirrored the peak in cases observed during each infection wave. Our study illustrates the changes in clinical presentation and severity observed with the different coronavirus variants.

Differences in the Clinical Manifestations and Host Immune Responses to SARS-CoV-2 Variants in Children Compared to Adults

The COVID-19 pandemic challenged the medical field to rapidly identify and implement new approaches to the diagnosis, treatment and prevention of SARS-CoV-2 infections. The scientific community also needed to rapidly initiate basic, translational, clinical and epidemiological studies to understand the pathophysiology of this new family of viruses, which continues to evolve with the emergence of new genetic variants. One of the earliest clinical observations that provided a framework for the research was the finding that, in contrast to most other respiratory viruses, children developed less severe acute and post-acute disease compared to adults. Although the clinical manifestations of SARS-CoV-2 infection changed with each new wave of the pandemic, which was dominated by evolving viral variants, the differences in severity between children and adults persisted. Comparative immunologic studies have shown that children mount a more vigorous local innate response characterized by the activation of interferon pathways and recruitment of innate cells to the mucosa, which may mitigate against the hyperinflammatory adaptive response and systemic cytokine release that likely contributed to more severe outcomes including acute respiratory distress syndrome in adults. In this review, the clinical manifestations and immunologic responses in children during the different waves of COVID-19 are discussed.

Post-COVID-19 Condition in Children 6 and 12 Months After Infection

Importance

There is a need to understand the long-term outcomes among children infected with SARS-CoV-2.

Objective

To quantify the prevalence of post-COVID-19 condition (PCC) among children tested for SARS-CoV-2 infection in pediatric emergency departments (EDs).

Design, Setting, and Participants

Multicenter, prospective cohort study at 14 Canadian tertiary pediatric EDs that are members of the Pediatric Emergency Research Canada network with 90-day, 6-month, and 12-month follow-up. Participants were children younger than 18 years who were tested for SARS-CoV-2 infection between August 2020 and February 2022. Data were analyzed from May to November 2023.

Exposure

The presence of SARS-CoV-2 infection at or within 14 days of the index ED visit.

Main Outcomes and Measures

Presence of symptoms and QoL reductions that meet the PCC definition. This includes any symptom with onset within 3 months of infection that is ongoing at the time of follow-up and affects everyday functioning. The outcome was quantified at 6 and 12 months following the index ED visit.

Results

Among the 5147 children at 6 months (1152 with SARS-CoV-2 positive tests and 3995 with negative tests) and 5563 children at 12 months (1192 with SARS-CoV-2 positive tests and 4371 with negative tests) who had sufficient data regarding the primary outcome to enable PCC classification, the median (IQR) age was 2.0 (0.9-5.0) years, and 2956 of 5563 (53.1%) were male. At 6-month follow-up, symptoms and QoL changes consistent with the PCC definition were present in 6 of 1152 children with positive SARS-CoV-2 tests (0.52%) and 4 of 3995 children with negative SARS-CoV-2 tests (0.10%; absolute risk difference, 0.42%; 95% CI, 0.02% to 0.94%). The PCC definition was met at 12 months by 8 of 1192 children with positive SARS-CoV-2 tests (0.67%) and 7 of 4371 children with negative SARS-CoV-2 tests (0.16%; absolute risk difference, 0.51%; 95% CI, 0.06 to 1.08%). At 12 months, the median (IQR) PedsQL Generic Core Scale scores were 98.4 (90.0-100) among children with positive SARS-CoV-2 tests and 98.8 (91.7-100) among children with negative SARS-CoV-2 tests (difference, -0.3; 95% CI, -1.5 to 0.8; P = .56). Among the 8 children with SARS-CoV-2 positive tests and PCC at 12-month follow-up, children reported respiratory (7 of 8 patients [88%]), systemic (3 of 8 patients [38%]), and neurologic (1 of 8 patients [13%]) symptoms.

Conclusions and Relevance

In this cohort study of children tested for SARS-CoV-2 infection in Canadian pediatric EDs, although children infected with SARS-CoV-2 reported increased chronic symptoms, few of these children developed PCC, and overall QoL did not differ from children with negative SARS-CoV-2 tests.

Changes in symptoms and characteristics of COVID-19 patients across different variants: two years study using neural network analysis

BACKGROUND

Considering the fact that COVID-19 has undergone various changes over time, its symptoms have also varied. The aim of this study is to describe and compare the changes in personal characteristics, symptoms, and underlying conditions of individuals infected with different strains of COVID-19.

METHODS

This descriptive-analytical study was conducted on 46,747 patients who underwent PCR testing during a two-year period from February 22, 2020 to February 23, 2022, in South Khorasan province, Iran. Patient characteristics and symptoms were extracted based on self-report and the information system. The data were analyzed using logistic regression and artificial neural network approaches. The R software was used for analysis and a significance level of 0.05 was considered for the tests.

RESULTS

Among the 46,747 cases analyzed, 23,239 (49.7%) were male, and the mean age was 51.48 ± 21.41 years. There was a significant difference in symptoms among different variants of the disease (p < 0.001). The factors with a significant positive association were myalgia (OR: 2.04; 95% CI, 1.76 - 2.36), cough (OR: 1.93; 95% CI, 1.68-2.22), and taste or smell disorder (OR: 2.62; 95% CI, 2.1 - 3.28). Additionally, aging was found to increase the likelihood of testing positive across the six periods.

CONCLUSION

We found that older age, myalgia, cough and taste/smell disorder are better factors compared to dyspnea or high body temperature, for identifying a COVID-19 patient. As the disease evolved, chills and diarrhea, demonstrated prognostic strength as in Omicron.

True prevalence of long COVID in children: a narrative review

Contrary to what is true for adults, little is known about pediatric long COVID (LC). Studies enrolling children are relatively few and extremely heterogeneous. This does not allow to draw definitive conclusions on the frequency and pathogenesis of pediatric LC and limits the development of appropriate and effective measures to contain the clinical, social and economic impact of this condition on the pediatric population. Depending on the methods used to collect and analyze data, studies have found that the incidence rate of pediatric LC may vary from about 25% to less than 5%. However, despite true prevalence of pediatric LC cannot be exactly defined, studies comparing children with previous COVID-19 and uninfected controls have shown that most of the clinical manifestations detected in infected children, mainly mood symptoms, mental health disorders and heart abnormalities could be diagnosed with similar frequency and severity in uninfected subjects also. This seems to indicate that SARS-CoV-2 is the cause of pediatric LC only in a part of children and other factors play a relevant role in this regard. Pandemic itself with the persistent disruption of child lives may have caused persistent stress in all the pediatric population causing mood symptoms, mental health disorders or several organ and body system functional alterations, regardless SARS-CoV-2 infection. These suppositions suggest the need for long-term physical control of all the children after COVID-19 especially when they were already suffering from an underlying disease or have had a severe disease. Moreover, attention should be paid to the assessment of change in children's emotional and behavioral functioning in order to assure adequate interventions for the best emotional and behavioral well being. However, whatever its origin, it seems highly likely that the prevalence of the pediatric LC is set to decline in the future. Preliminary observations seem to suggest that recently developed SARS-CoV-2 variants are associated with less severe COVID-19. This suggests that, as already seen in adults, a lower number of pediatric virus-associated LC cases should occur. Furthermore, the use of COVID-19 vaccines, reducing incidence and severity of SARS-CoV-2 infection, may reduce risk of LC development. Finally, elimination of restrictive measures should significantly reduce mood symptoms and mental health disorders.

Associations between COVID-19 Vaccination Status and Self-Reported SARS-CoV-2 Infection among 8538 Children Aged 3-17 Years during a Massive COVID-19 Outbreak after China Changed Its Zero-COVID-19 Policy: A Cross-Sectional Survey

This study aimed to investigate the associations between COVID-19 vaccination status and self-reported SARS-CoV-2 infection among children and adolescents aged 3-17 years during a massive COVID-19 outbreak after China changed its zero COVID policy. A cross-sectional online survey was conducted between 1 and 9 March 2023. Participants were the parents of children studying in kindergartens, primary schools, or secondary schools in Shenzhen. Convenient sampling was used. All kindergartens, primary schools, and secondary schools in the Longhua District of Shenzhen invited the parents of children and adolescents attending the schools. Interested parents completed an online survey. Multivariate logistic regression was fitted. Among 8538 participants, 40.9% self-reported that their children had SARS-CoV-2 infection after 7 December 2022, where 92.9% of them received two doses of the COVID-19 vaccines, and 74.6% received their second dose for more than six months. In multivariate analysis, children who received their second dose of the COVID-19 vaccination for no more than three months had a lower SARS-CoV-2 infection rate compared to unvaccinated children (<1 month: AOR: 0.17, 95% CI: 0.07, 0.44; 1-3 months: AOR: 0.54, 95% CI: 0.41, 0.75). The duration of protection conferred by the primary COVID-19 vaccination series was relatively short among children. A booster dose should be considered for children.

Epidemiology and SARS-CoV-2 Infection Patterns among Youth Followed at a Large Los Angeles Health Network during 2020-2022: Clinical Presentation, Prevalent Strains, and Correlates of Disease Severity

BACKGROUND

Outcomes of SARS CoV-2 infection in infants, children and young adults are reported less frequently than in older populations. The evolution of SARS-CoV-2 cases in LA County youths followed at a large health network in southern California over two years was evaluated.

METHODS

A prospective cohort study of patients aged 0-24 years diagnosed with COVID-19 was conducted. Demographics, age distribution, disease severity, circulating variants of concern (VOCs), and immunization rates were compared between first and second pandemic years. Logistic regression estimated odds ratios (OR) and 95% confidence intervals (CI) of factors associated with severe/critical COVID-19.

RESULTS

In total, 61,208 patients 0-24 years of age were tested for SARS-CoV-2 by polymerase chain reaction (PCR); 5263 positive patients (8.6%) with available data were identified between March 2020 and March 2022. In Year 1, 5.8% (1622/28,088) of youths tested positive, compared to 11% (3641/33,120) in Year 2 (p < 0.001). Most youths had mild/asymptomatic illness over two years. SARS-CoV-2 positivity was >12% across all age groups in the second half of Year 2, when Omicron prevailed. Pulmonary disease was associated with higher risk of severe COVID-19 in both years (OR: 2.4, 95% CI: 1.4-4.3, p = 0.002, Year 1; OR: 11.3, 95% CI: 4.3-29.6, Year 2, p < 0.001). Receipt of at least one COVID-19 vaccine dose was protective against severe COVID-19 (OR: 0.3, 95% CI: 0.11-0.80, p < 0.05).

CONCLUSIONS

Despite different VOCs and higher rates of test positivity in Year 2 compared to Year 1, most youths with COVID-19 had asymptomatic/mild disease. Underlying pulmonary conditions increased the risk of severe COVID-19, while vaccination was highly protective against severe disease in youths.