Coronavirus Disease 2019 (COVID-19) in Children: Vulnerable or Spared? A Systematic Review

Cardiac Function in Pediatric Patients with MIS-C Using Speckle Tracking and Conventional Echocardiography: A Longitudinal, Single-Center Study

Cardiovascular involvement in Multisystem Inflammatory Syndrome in Children (MIS-C), a potential consequence of coronavirus disease-2019 (COVID-19), is common. Conventional transthoracic echocardiography (TTE) provides primary data on the function of the left and right ventricles, while Speckle Tracking Echocardiography (STE) is more sensitive. This study aims to assess longitudinal cardiac function using STE in these patients. This longitudinal study was conducted from late 2021 to early 2022 at Imam Hossein Children's Hospital, Isfahan. Cardiac function was assessed by STE at the time of diagnosis and again two months later. Demographics, clinical characteristics, ECG interpretations, imaging studies, and serum cardiac marker levels were collected. Thirty-five pediatric patients with a mean age of 5.1 years (range: 4 months to 17 years) were included and prospectively followed. Twenty-nine of them, comprising 14 males (48.3%) and 15 females (51.7%), underwent STE and were compared with 29 healthy age- and sex-matched children. Factors related to adverse events included reduced myocardial function, enlarged left atrium or ventricle, and mitral regurgitation (MR). Patients with comorbidities affecting strain measurements were excluded from the strain analyses. A significant difference was observed between the groups in regional strains in the basal and apical septal and middle lateral regions. Global strain rate (GLS) and strain rates were not significantly different but were still lower than the control group. Twenty percent of patients had abnormal GLS but normal left ventricular ejection fraction (LVEF). All patients exhibited reduced segmental myocardial strain in at least one segment. Four out of 26 recovered patients without comorbidities had abnormal GLS at follow-up, despite normal LVEF. STE proves more useful than conventional echocardiography in patients with MIS-C, revealing subclinical cardiac injury in the acute and post-acute phases.

Changes in Parents' COVID-19 Vaccine Hesitancy for Children Aged 3-17 Years before and after the Rollout of the National Childhood COVID-19 Vaccination Program in China: Repeated Cross-Sectional Surveys

China started to implement COVID-19 vaccination programs for children in July 2021. This study investigated the changes in parents’ COVID-19 vaccine hesitancy for children before and after the vaccination program rollout. Repeated cross-sectional online surveys among full-time adult factory workers were conducted in Shenzhen, China. This analysis was based on 844 (first round) and 1213 parents (second round) who had at least one child aged 3−17 years. The prevalence of vaccine hesitancy for children aged 3−11 years dropped from 25.9% (first round) to 17.4% (second round), while such a prevalence for children aged 12−17 years dropped from 26.0% (first round) to 3.5% (second round) (p < 0.001). Positive attitudes, a perceived subjective norm, and perceived behavioral control related to children’s COVID-19 vaccination were associated with lower vaccine hesitancy in both rounds. In the second round and among parents with children aged 3−11 years, negative attitudes and exposure to information on SARS-CoV-2 infection after receiving a primary vaccine series were associated with higher vaccine hesitancy, while exposure to experiences shared by vaccine recipients and infectiousness of variants of concern were associated with lower vaccine hesitancy. Regular monitoring of vaccine hesitancy and its associated factors among parents should be conducted to guide health promotion.

Development of an Enzyme-Linked Immunosorbent Assay (ELISA) for Accurate and Prompt Coronavirus Disease 2019 (COVID-19) Diagnosis Using the Rational Selection of Serological Biomarkers

Prompt COVID-19 diagnosis is urgently required to support infection control measures. Currently available serological tests for measuring SARS-CoV-2 antibodies use different target antigens, although their sensitivity and specificity presents a challenge. We aimed to develop an "in-house" serological ELISA to measure antibodies against SARS-CoV-2 by combining different protein antigens. Sera (n = 44) from COVID-19-confirmed patients were evaluated against different SARS-CoV-2 protein antigens and all potential combinations using ELISA. Patients' sera were also evaluated against commercially available ELISA diagnostic kits. The mixture containing RBD 2.5 μg/mL, S2 1 μg/mL and N 1.5 μg/mL was found to be the most potent. Plates were incubated with patients' sera (1:100), and goat anti-human alkaline phosphatase-conjugated IgG, ΙgM and IgA antibody was added. The cut-off value for each assay was determined using the mean optical density plus two standard deviations of pre-pandemic controls. The "in-house" ELISA displayed 91% sensitivity and 97% specificity for IgG antibodies, whereas its sensitivity and specificity for IgM and IgA were 75% and 95% and 73% and 91%, respectively. The "in-house" ELISA developed here combined three SARS-CoV-2 antigens (RBD, S2 and N) as capture antigens and displayed comparable and even higher sensitivity and specificity than otherwise quite reliable commercially available ELISA diagnostic kits.

Protecting Families: A Qualitative Study on the Implementation of Protective Measures to Prevent COVID-19 Transmission

BACKGROUND: Health protocol compliance among family members can help curb the spread of COVID-19. However, not all families or family members can easily navigate the changes brought about by the pandemic; hence, minimizing virus transmission remains a challenge. AIM: Therefore, observing how families implement health protocols in daily life will reveal the challenges and opportunities, and inform public health policies. METHODS: We conducted a qualitative study by collecting data through phone interviews from November 2020 to February 2021. Eighteen families with a total of 30 individuals participated in this study. The interview data were transcribed verbatim and analyzed using thematic analysis. RESULTS: The analysis shows that participants were actively involved in implementing protective measures to prevent transmission among their family members. Five themes emerged from the data, namely fundamental concerns, restraints and constraints, pandemic roles, compromises, and intergenerational attitudes. The themes described the families’ lives during the pandemic, their efforts in protecting family members, and the dynamic within the families related to the implementation of COVID-19 protective measures. CONCLUSION: This study indicates that families could play a key role in both protecting and compromising the health of their family members. Families respond to the health crisis actively, but at times increase the risk to virus exposure because they have to continue going about their daily lives.

Serological Profile of Children and Young Adults with at Least One SARS-CoV-2 Positive Cohabitant: An Observational Study

At the end of 2019, a new disease caused by the novel coronavirus SARS-CoV-2 appeared in Wuhan Province in China. Children seemed to be infected less frequently than adults, and family clusters seemed to play an important role in the spread of the pandemic. The aim of this study is to evaluate the serological profile of children and young adults between 4 and 16 years of age in order to assess the transmission patterns of COVID-19 between cohabitants. The subjects lived with at least one cohabitant who tested positive for the disease using a nasopharyngeal swab. To avoid contact with the disease, families were interviewed by telephone. Forty-nine children and adolescents with a mean age of 11 years were then subjected to a rapid lateral flow chromatographic test. Of them, seven (14.3%) were immunoglobulin G (IgG)-positive, and four (8.2%) were immunoglobulin M (IgM)-positive. In total, 16.3% of the tested sample had antibodies against SARS-CoV-2: this may confirm the lower vulnerability of children to COVID-19, despite the small sample size. The time from the negativization of the cohabitant until the test day may have influenced the results, especially when this timeframe is wide.

COVID-19-The Potential Beneficial Therapeutic Effects of Spironolactone during SARS-CoV-2 Infection

In March 2020, coronavirus disease 2019 (COVID-19) caused by SARS-CoV-2 was declared a global pandemic by the World Health Organization (WHO). The clinical course of the disease is unpredictable but may lead to severe acute respiratory infection (SARI) and pneumonia leading to acute respiratory distress syndrome (ARDS). It has been shown that pulmonary fibrosis may be one of the major long-term complications of COVID-19. In animal models, the use of spironolactone was proven to be an important drug in the prevention of pulmonary fibrosis. Through its dual action as a mineralocorticoid receptor (MR) antagonist and an androgenic inhibitor, spironolactone can provide significant benefits concerning COVID-19 infection. The primary effect of spironolactone in reducing pulmonary edema may also be beneficial in COVID-19 ARDS. Spironolactone is a well-known, widely used and safe anti-hypertensive and antiandrogenic medication. It has potassium-sparing diuretic action by antagonizing mineralocorticoid receptors (MRs). Spironolactone and potassium canrenoate, exerting combined pleiotropic action, may provide a therapeutic benefit to patients with COVID-19 pneumonia through antiandrogen, MR blocking, antifibrotic and anti-hyperinflammatory action. It has been proposed that spironolactone may prevent acute lung injury in COVID-19 infection due to its pleiotropic effects with favorable renin–angiotensin–aldosterone system (RAAS) and ACE2 expression, reduction in transmembrane serine protease 2 (TMPRSS2) activity and antiandrogenic action, and therefore it may prove to act as additional protection for patients at highest risk of severe pneumonia. Future prospective clinical trials are warranted to evaluate its therapeutic potential.

Vaccine-Induced CD8+ T Cell Responses in Children: A Review of Age-Specific Molecular Determinants Contributing to Antigen Cross-Presentation

Infections are most common and most severe at the extremes of age, the young and the elderly. Vaccination can be a key approach to enhance immunogenicity and protection against pathogens in these vulnerable populations, who have a functionally distinct immune system compared to other age groups. More than 50% of the vaccine market is for pediatric use, yet to date vaccine development is often empiric and not tailored to molecular distinctions in innate and adaptive immune activation in early life. With modern vaccine development shifting from whole-cell based vaccines to subunit vaccines also comes the need for formulations that can elicit a CD8+ T cell response when needed, for example, by promoting antigen cross-presentation. While our group and others have identified many cellular and molecular determinants of successful activation of antigen-presenting cells, B cells and CD4+ T cells in early life, much less is known about the ontogeny of CD8+ T cell induction. In this review, we summarize the literature pertaining to the frequency and phenotype of newborn and infant CD8+ T cells, and any evidence of induction of CD8+ T cells by currently licensed pediatric vaccine formulations. In addition, we review the molecular determinants of antigen cross-presentation on MHC I and successful CD8+ T cell induction and discuss potential distinctions that can be made in children. Finally, we discuss recent advances in development of novel adjuvants and provide future directions for basic and translational research in this area.

Quantifying the shift in social contact patterns in response to non-pharmaceutical interventions

Social contact mixing plays a critical role in influencing the transmission routes of infectious diseases. Moreover, quantifying social contact mixing patterns and their variations in a rapidly evolving pandemic intervened by changing public health measures is key for retroactive evaluation and proactive assessment of the effectiveness of different age- and setting-specific interventions. Contact mixing patterns have been used to inform COVID-19 pandemic public health decision-making; but a rigorously justified methodology to identify setting-specific contact mixing patterns and their variations in a rapidly developing pandemic, which can be informed by readily available data, is in great demand and has not yet been established. Here we fill in this critical gap by developing and utilizing a novel methodology, integrating social contact patterns derived from empirical data with a disease transmission model, that enables the usage of age-stratified incidence data to infer age-specific susceptibility, daily contact mixing patterns in workplace, household, school and community settings; and transmission acquired in these settings under different physical distancing measures. We demonstrated the utility of this methodology by performing an analysis of the COVID-19 epidemic in Ontario, Canada. We quantified the age- and setting (household, workplace, community, and school)-specific mixing patterns and their evolution during the escalation of public health interventions in Ontario, Canada. We estimated a reduction in the average individual contact rate from 12.27 to 6.58 contacts per day, with an increase in household contacts, following the implementation of control measures. We also estimated increasing trends by age in both the susceptibility to infection by SARS-CoV-2 and the proportion of symptomatic individuals diagnosed. Inferring the age- and setting-specific social contact mixing and key age-stratified epidemiological parameters, in the presence of evolving control measures, is critical to inform decision- and policy-making for the current COVID-19 pandemic.

How to Early Identify and Prevent the SARS-CoV-2 Infection in Children for Families?

Importance: COVID-19 has become a worldwide pandemic. Many countries have reported cases of infection in children and newborns, and there is a trend of significantly increasing infections among these populations. Therefore, it is important to provide advice and guidance for the prevention and control of COVID-19 in children. Observations: Children are as susceptible to SARS-CoV-2 infection as adults. The manifestations in children are atypical, and children are much less likely to have critical cases. If children are infected, they may play an important role in the spread of SARS-CoV-2 because their symptoms are less obvious and less likely to be detected. To prevent COVID-19 from spreading among children, efforts to prevent, and control the infection should be increased by controlling the source of infection, blocking the route of transmission and protecting the susceptible population. Conclusions and Relevance: The early identification of the COVID-19 in children and the protection of families are important measures to prevent the continued spread of SARS-CoV-2.