Effectiveness of BNT162b2 (Pfizer-BioNTech) mRNA Vaccination Against Multisystem Inflammatory Syndrome in Children Among Persons Aged 12-18 Years - United States, July-December 2021

Design and rationale of the COVID vaccine-associated myocarditis/pericarditis (CAMP) study

BACKGROUND

Minimal data are available on mid- and long-term outcomes following COVID-19 vaccine-associated myocarditis/pericarditis. The COVID Vaccine-Associated Myocarditis/Pericarditis (CAMP) study aims to characterize the mid- and long-term sequelae of myocarditis/pericarditis following administration of any Pfizer-BioNTech COVID-19 vaccine (herein referred to as COMIRNATY®). Herein we describe the rationale and design of CAMP.

METHODS

This ongoing and actively enrolling multicenter observational cohort study across 32 North American pediatric cardiac centers will include at least 200 patients <21 years-old who presented ≤21 days from COMIRNATY® vaccination and meet the Centers for Disease Control and Prevention (CDC) case definition of probable or confirmed myocarditis/pericarditis or isolated pericarditis. The comparison cohort will consist of 100 patients <21 years-old with COVID-19 associated myocarditis/pericarditis, including those who meet the contemporaneous CDC case definition of multisystem inflammatory syndrome (MIS-C). The study will collect detailed hospital and follow-up data for up to 5 years following illness onset. Electrocardiograms, echocardiograms, and cardiac magnetic resonance (CMR) examinations will be interpreted in core laboratories. The primary outcomes are 1) composite of left ventricular ejection fraction <55% by echocardiogram, findings of myocarditis by original or revised Lake Louise criteria on CMR, and/or the presence of high-grade arrhythmias or conduction system disturbances at 6 months after myocarditis/pericarditis onset; 2) complications, such as death, and non-cardiac morbidities; and 3) patient-reported outcomes of global health, functional status, and quality of life. Analyses will include descriptive statistics and regression modeling.

CURRENT STATUS

Still enrolling, with 273 participants currently enrolled as of 10/16/2024 (173 vaccine-associated myocarditis/pericarditis, 100 COVID-19-associated myocarditis/pericarditis) CONCLUSIONS: With long-term follow-up and core laboratories for standardized assessments of cardiac testing, the CAMP study will make important contributions to our understanding of the mid- and long-term cardiac and non-cardiac sequelae of COVID-19 vaccine-associated myocarditis/pericarditis.

An Update on Multi-System Inflammatory Syndrome in Children

PURPOSE

To summarize the latest research on the epidemiology, pathogenesis, diagnosis, and treatment of multisystem inflammatory syndrome in children (MIS-C).

RECENT FINDINGS

The epidemiology of MIS-C has been dynamic since its initial description. The pathogenesis remains poorly understood. Case definitions of MIS-C have evolved over time, and practice patterns for treating MIS-C are variable with generally positive long-term outcomes yet persistent changes noted. MIS-C has become less prevalent and less severe over time, yet racial and ethnic disparities persist, and vaccination against COVID-19 is highly effective in preventing this disease. The link between acute infection and subsequent inflammation is not well understood, with growing evidence describing its immunologic signature. Newer case definitions require excluding other inflammatory conditions, including Kawasaki Disease (KD), before diagnosing MIS-C. Corticosteroid monotherapy may be non-inferior to IVIg alone or combination IVIg plus corticosteroids for initial treatment, distinguishing the approaches to MIS-C and KD. A wide range of biologic therapies have been employed for rescue therapy with general success and no clear benefit of one over another. Despite reports of a high rate of coronary artery abnormality regression and resolution of heart failure, long-term studies suggest persistent changes to cardiac function. The long-term effects of MIS-C continue to be active areas of research.

Risk of Kawasaki Disease/Multisystem Inflammatory Syndrome Following COVID-19 Vaccination in Korean Children: A Self-Controlled Case Series Study

BACKGROUND

Rare cases of Kawasaki disease (KD) and multisystem inflammatory syndrome in children (MIS-C) have been reported following the coronavirus disease 2019 (COVID-19) vaccination; however, the association between COVID-19 vaccination and the risk of developing KD/MIS-C has not yet been established.

METHODS

We conducted a self-controlled case series analysis using a large-linked database that connects the COVID-19 immunization registry with nationwide claims data. We identified individuals aged < 18 years who received their initial COVID-19 vaccination and had a KD/MIS-C diagnosis with a prescription for intravenous immunoglobulin or corticosteroids between October 18, 2021, and April 15, 2023. The observation period was set as 240 days from the date of the COVID-19 vaccination. The risk window was 60 days after vaccination, with the remaining observation period serving as the control window. The incidence rate ratios (IRRs) and 95% confidence intervals (CIs) in the risk versus control windows were estimated using the conditional Poisson regression model. We further analyzed the vaccine doses and types for secondary analysis. We also performed subgroup analyses stratified by sex, age, comorbidities, and other conditions and sensitivity analyses by varying the length of the risk window and outcome definition.

RESULTS

Among 2,369,490 individuals who received the COVID-19 vaccination, 12 cases of KD/MIS-C were identified, which included five and seven patients in the risk and control windows, respectively. There was no increased risk of KD/MIS-C within the 60-day period of vaccination (IRR, 0.53; 95% CI, 0.17-1.60). Secondary subgroup and sensitivity analyses showed no significant increase in the risk of KD/MIS-C after COVID-19 vaccination, which is consistent with the results of the main analysis.

CONCLUSION

The results of this nationwide study suggest that the risk of developing KD/MIS-C did not increase after COVID-19 vaccination. However, owing to the lack of a sufficient number of cases, future studies utilizing multinational long-term follow-up databases should be conducted. Considering the increasing incidence of KD/MIS-C and the limited understanding of its precise biological mechanisms, additional research on KD/MIS-C is warranted.

Parental decisions regarding the vaccination of children and adolescents against SARS-CoV-2 from 2020 to 2023: A descriptive longitudinal study of parents and children in Montreal, Canada

BACKGROUND

Given the growing evidence on the benefits of hybrid immunity, continued monitoring of vaccine uptake is warranted, particularly of socio-demographic subgroups with early vaccine hesitancy. Racial/ethnic and lower income groups experienced a high infection incidence, but few studies account for the child's history of SARS-CoV-2 infection on the parent's decision to vaccinate their child.

METHODS

EnCORE is a SARS-CoV-2 pediatric cohort study comprising five rounds of data collection from 2020 to 2023, with parental questionnaires at each round. Parent's responses on their intention to vaccinate their child and their reasons were summarized descriptively. Vaccine uptake was estimated through time and in relation to participant characteristics, using multivariable regression to adjust for covariates including a history of PCR/serology-confirmed SARS-CoV-2 infection prior to vaccine eligibility. At study end, we estimated the average time lapsed from last vaccine dose.

RESULTS

The samples for vaccine uptake and intention to vaccinate analyses were 631 and 1137 participants, respectively. At study end, uptake was 88 % but approximately 49 % of 2-to-4-year-olds remained unvaccinated (95 % CI 39.0, 58.1) and for vaccinated participants the median time since last vaccination was 353 days. In regression analyses, after adjusting for infection prior to vaccine eligibility and other covariates, we found approximately a two-fold increase in unvaccinated status associated with the parent's identification as a racial/ethnic minority and with household income in the lowest sample tercile (minority: adjusted relative risk [aRR] 2.45, 95 % CI 1.56, 3.86; income: aRR 1.76, 95 % CI 1.17, 2.66).

CONCLUSION

By mid-2023, most participants were not protected by vaccine-induced antibodies, because they were unvaccinated or several months had lapsed from their last dose. A COVID-19 infection prior to vaccine eligibility was associated with a greater risk of remaining unvaccinated but did not fully account for low uptake in ethnic/racial minorities and lower income groups.

Safety and Immunogenicity of an mRNA-1273 Booster in Children

BACKGROUND

A 2-dose mRNA-1273 primary series in children aged 6 months-5 years (25 µg) and 6-11 years (50 µg) had an acceptable safety profile and was immunogenic in the phase 2/3 KidCOVE study. We present data from KidCOVE participants who received an mRNA-1273 booster dose.

METHODS

An mRNA-1273 booster dose (10 µg for children aged 6 months-5 years; 25 µg for children aged 6-11 years; age groups based on participant age at enrollment) was administered ≥6 months after primary series completion. The primary safety objective was the safety and reactogenicity of an mRNA-1273 booster dose. The primary immunogenicity objective was to infer efficacy of an mRNA-1273 booster dose by establishing noninferiority of neutralizing antibody (nAb) responses after a booster in children versus nAb responses observed after the mRNA-1273 primary series in young adults (18-25 years) from the pivotal efficacy study. Data were collected from March 2022 to June 2023.

RESULTS

Overall, 153 (6 months-5 years) and 2519 (6-11 years) participants received an mRNA-1273 booster dose (median age at receipt of booster: 2 and 10 years, respectively). The booster dose safety profile was generally consistent with that of the primary series in children; no new safety concerns were identified. An mRNA-1273 booster dose elicited robust nAb responses against ancestral SARS-CoV-2 among children and met prespecified noninferiority success criteria versus responses observed after the primary series in young adults.

CONCLUSIONS

Safety and immunogenicity data support administration of an mRNA-1273 booster dose in children aged 6 months to 11 years.

CLINICAL TRIALS REGISTRATION

NCT04796896 (Clinicaltrials.gov).

Prior infections and effectiveness of SARS-CoV-2 vaccine in test-negative studies: a systematic review and meta-analysis

Prior infection with SARS-CoV-2 can provide protection against infection and severe COVID-19. We aimed to determine the impact of preexisting immunity on vaccine effectiveness (VE) estimates. We systematically reviewed and meta-analyzed 66 test-negative design studies that examined VE against infection or severe disease (hospitalization, intensive care unit admission, or death) for primary vaccination series. Pooled VE among studies that included people with prior COVID-19 infection was lower against infection (77%; 95% CI, 72-81) and severe disease (86%; 95% CI, 83-89) compared with studies that excluded people with prior COVID-19 infection (pooled VE against infection: 87% [95% CI, 85-89]; pooled VE against severe disease: 93% [95% CI, 91-95]). There was a negative correlation between VE estimates against infection and severe disease, and the cumulative incidence of cases before the start of the study or incidence rates during the study period. We found clear empirical evidence that higher levels of preexisting immunity were associated with lower VE estimates. Prior infections should be treated as both a confounder and effect modificatory when the policies target the whole population or are stratified by infection history, respectively.

In-hospital unfavorable outcomes of MIS-C during 2020-2022: a systematic review

Studies on the severity in multisystem inflammatory syndrome in children (MIS-C) show heterogeneous results and may not reflect a global perspective. This systematic review aims to estimate the frequency of in-hospital unfavorable outcomes in patients with MIS-C over the 3 years since the onset of the SARS-CoV-2 pandemic. A systematic search was conducted in Medline, Scopus, Embase, Cochrane, Web of Science, Scielo, and preprint repositories until December 15, 2022. Study selection and data extraction were evaluated independently. The primary outcomes were intensive care unit (ICU) admission, invasive mechanical ventilation (IMV), and death. Additionally, we evaluated cardiovascular-related outcomes. We performed a random-effects model meta-analysis and assessed the certainty of the evidence. Fifty-seven studies (n = 13 254) were included. The frequency of ICU admission was 44.7% (95% CI 38.8-50.7), 11.9% for IMV (95% CI 9.6-14.4), and 2.0% for death (95% CI 1.3-3.0). The requirement of vasoactive/inotropic drugs was 40.1% (95% CI 35.9-44.4), 7.9% for coronary aneurysm (95% CI 4.1-12.7), 30.7% for decreased left ventricle ejection fraction (LVEF) (95% CI 26.3-35.4), and 29.7% for myocarditis (95% CI 18.4-42.4). We assess the included evidence as being of very low certainty. Finally, excess COVID-19 mortality by country and the diagnostic criteria for MIS-C (CDC compared to WHO) were associated with a higher frequency of ICU admissions. The year of study conduction (2022 compared to 2020) was associated with a lower frequency of IMV.

CONCLUSION

The frequency of in-hospital unfavorable outcomes in patients with MIS-C was high. Well-designed studies are needed to explore other heterogeneity sources.

PROTOCOL REGISTRATION

CRD42021284878.

WHAT IS KNOWN

• Multisystem inflammatory syndrome in children (MIS-C) is a serious post-infectious condition linked to SARS-CoV-2. Studies on the severity of MIS-C show heterogeneous results. These findings may not be representative of the reality in other regions, making it challenging to draw generalizable conclusions.

WHAT IS NEW

• Over the 3 years since the onset of the SARS-CoV-2 pandemic, our systematic review has shown that the frequency of in-hospital unfavorable outcomes in patients with MIS-C is high, with a very low certainty of the evidence. Our results reflect the reality from a global perspective, across different countries with varying income levels. • The main sources of heterogeneity in the frequency of severe outcomes could be explained by the excess mortality due to COVID-19 in each country, the type of diagnostic criteria for MIS-C, and the year the study was conducted.

Nationwide Survey of Multisystem Inflammatory Syndrome in Children Associated with Coronavirus Disease 2019 in Japan

BACKGROUND

Multisystem inflammatory syndrome in children (MIS-C) presents some clinical overlap with Kawasaki disease (KD). Although KD is common in Japan, the clinical characteristics of MIS-C in Japan remain unknown. Therefore, we aimed to determine the epidemiological and clinical features of MIS-C in Japan.

METHODS

Using a case reporting form, a nationwide registry was created between November 2020 and March 2023, involving 2,080 facilities throughout Japan. We prospectively and retrospectively enrolled patients with MIS-C. The primary outcomes were the number and incidence rates of children with MIS-C. The secondary outcomes included clinical features, such as KD phenotype, organ involvement, shock, intensive care unit admission, and coronary artery lesions.

RESULTS

Among 398 patients registered, central review identified 129 MIS-C cases (mean age: 8·8 ± 3·7 years). The overall incidence rate was estimated to be 1·5 per 100,000 COVID-19 cases, exhibiting a decline as the COVID-19 pandemic progressed, from 12·3 cases (Pre-Delta) to 1·3 cases (Omicron); 80% of MIS-C cases occurred during the Omicron variant predominant period, and 72% of children with MIS-C met the KD criteria. Cardiovascular (88%) and gastrointestinal (90%) involvement were frequent. In Japan, MIS-C cases showed comparatively less severe clinical features, with shock in 29% and admission to the intensive care unit in 12% of cases. Coronary artery lesions were identified in 15 cases (11·6%), irrespective of the presence of shock. No fatalities were reported.

CONCLUSION

The incidence of MIS-C was low in Japan. The clinical features distinctively exhibited a more KD-like phenotype, with less severe clinical features.

Long-term Health Outcomes After Hospital Discharge Among Children Hospitalized for MIS-C or COVID-19, September 29, 2021, to June 21, 2022

BACKGROUND

The long-term effects of children hospitalized with multisystem inflammatory syndrome in children (MIS-C) or acute COVID-19 are not well known. Our objective was to determine long-term outcomes.

METHODS

Children hospitalized with MIS-C or COVID-19 at 3 US hospitals from March 2020, through February 2021 were followed to assess health through 2 years post-hospitalization using medical records and patient surveys.

RESULTS

Medical record abstraction was performed for 183 patients hospitalized with MIS-C, 53 of whom participated in surveys, and 97 patients hospitalized with COVID-19, 35 of whom participated in surveys. Patients with MIS-C were younger (median, 9 vs. 14 years of age for COVID-19 patients; P = 0.004), more frequently male (62% vs. 39%; P < 0.001) and had more cardiac (14% vs. 2%; P = 0.001) and neurologic sequelae (8% vs. 1%; P = 0.023). Children with COVID-19 more often had other comorbidities (59% vs. 19%; P < 0.001). Full mental recovery at the time of survey 2 (median, 16 months post-hospitalization for patients with MIS-C and 20 months for patients with COVID-19) was 85% and 88%, respectively; full physical recovery was 87% and 81%, respectively; and nearly all had resumption of normal activities. Patients with MIS-C reported more frequent headache at 1 month (45% vs. 20%; P = 0.037). Patients with COVID-19 were more likely to report cough at 1 month (37% vs. 17%; P = 0.045). Fatigue persisted >1 year in 15%-20% of patients in both groups.

CONCLUSIONS

Approximately 20% of children with MIS-C and COVID-19 continued to have symptoms including fatigue and headache >1 year after hospital discharge. The duration of these findings emphasizes the importance of providers following patients until sequelae have resolved.

Characteristics of COVID-19-associated multisystemic inflammatory syndrome in children treated in a Peruvian hospital, 2020-2022

BACKGROUND

Motivation for the study. There are few studies describing the variation of COVID-19-associated multisystem inflammatory syndrome (MIS-C) in Peru across pandemic waves.

BACKGROUND

Main findings. Cases of MIS-C decreased during the first three years of the pandemic, with higher frequency in the second wave with clinical features similar to Kawasaki disease.

BACKGROUND

Implications. MIS-C is a post-infectious complication of SARS-CoV-2. Its diagnostic suspicion is important weeks after peak infections, especially in children who have not yet received COVID-19 vaccines.

BACKGROUND

This study aimed to describe the characteristics of multisystemic inflammatory syndrome associated with COVID-19 (MIS-C) in the first three years of the pandemic in children in a pediatric hospital in Peru. We conducted an observational, descriptive study with data from 73 patients and described the clinical and laboratory characteristics, treatment and complications according to the wave of the pandemic and whether they had shock. The median age was 6 years, gastrointestinal and mucocutaneous manifestations were frequent in the three waves. Kawasaki disease-like phenotype was present in 34 (46.6%) patients and 21 (28.8%) patients developed shock. The most commonly used treatment was immunoglobulin (95.9%), followed by acetylsalicylic acid (94.5%) and corticosteroid (86.3%). Five (7%) patients had coronary aneurysm and 17 (23.3%) were admitted to the intensive care unit (ICU). Patients with shock had greater laboratorial alteration and need for mechanical ventilation. In conclusion, MIS-C has decreased in the first three years of the pandemic, possibly due to COVID-19 vaccination in children.

Adverse effects of COVID-19 vaccine in the paediatric population: a focus on the cardiovascular system

The COVID-19 pandemic had an unprecedented impact on healthcare systems and exists globally. To control pandemic progression, COVID-19 vaccines were developed and licensed for use in the adult population in early 2021 and became available in paediatric cohorts several months later. Since then, several studies have reported adverse events and severe adverse events in the adult and paediatric cohorts. The question remains whether there exists a significant risk to paediatric COVID-19 vaccination. This study reviews the classification and presentation of severe adverse events and discusses relevant reports in the literature. An emphasis is put on cardiovascular severe adverse events and adverse events. This paper also provides current and future perspectives relative to the pandemic, its control, and the future of vaccine immunology.

SARS-CoV-2 Vaccination Coverage in Italian Children with Celiac Disease

Background: Celiac disease (CD) is the most common multisystemic autoimmune disorder affecting the pediatric population. However, little data is available regarding SARS-CoV-2 vaccination coverage in pediatric patients with CD. This study aims to evaluate the adherence to national recommendations for SARS-CoV-2 vaccination in children and adolescents with CD and its variation over time. Methods: We retrospectively analyzed medical charts and electronic registry records of SARS-CoV-2 vaccination of patients aged 0-19 years diagnosed with CD in a tertiary center. The vaccination coverage was evaluated according to age groups (young children, children, and adolescents), considering the patients' eligibility for vaccination at different times. Results: Among the 172 patients enrolled, 44.8% received at least one dose of the SARS-CoV-2 vaccine, showing no significant differences compared to the Italian population of similar age. Vaccination coverage demonstrated a progressive reduction after an initial peak (up to 65.5% in December 2021) concomitant with a gradual extension of vaccinable eligibility and falling SARS-CoV-2 infections. Histological diagnosis and the presence of other associated autoimmune diseases were associated with higher levels of adherence to vaccination. Conclusions: Adherence to the SARS-CoV-2 vaccination in young Italian children with CD was very low, while it was better in adolescents and patients with other associated autoimmune diseases. Vaccine hesitancy remains a concern, particularly among those diagnosed using the biopsy-sparing approach. Hesitancy increased during the pandemic period, suggesting the need for ongoing efforts to improve adherence to SARS-CoV-2 vaccination recommendations.

An overview of the COVID-19 pediatric vaccine program - The U.S. experience vaccinating children ages 6 months through 17 years

COVID-19 vaccination decreases risk for COVID-19 illness and severe disease in children, including multisystem inflammatory syndrome (MIS-C) and death. On December 13, 2020, CDC recommended COVID-19 vaccination for persons ages ≥16 years, with expansion on May 12, 2021, to adolescents ages 12-15 years; to children ages 5-11 years on November 2, 2021; and to children ages 6 months-4 years on June 18, 2022. Following each age-specific recommendation, the U.S. government collaborated with state and local governments, vaccine manufacturers, and numerous other public and private entities, to ensure rapid, broad, and equitable COVID-19 vaccine distribution to strategic locations across the country to maximize access. However, vaccination coverage among children has been lower than among adults and lower among younger children than adolescents. As of May 10, 2023, COVID-19 primary series vaccination coverage was 61.8% among U.S. children ages 12-17 years, 32.9% among those ages 5-11 years, and 5.5% among those ages 6 months-4 years. This manuscript describes the planning and implementation of the U.S. COVID-19 pediatric vaccine program, including successes (e.g., the availability of pharmacy vaccination to extend access beyond more traditional pediatric vaccine providers) and challenges (e.g., multi-dose vaccine vials instead of single-dose vials, leading to concerns about wastage) to provide a historical record of the program and to help inform planning and implementation of future routine or pandemic-related pediatric vaccination campaigns.

Building the U.S. COVID-19 vaccine effectiveness program: Past successes and future directions

COVID-19 vaccines were originally authorized in the United States in December 2020 on the basis of safety, immunogenicity, and clinical efficacy data from randomized controlled trials (RCTs). However, real-world vaccine effectiveness (VE) data are necessary to provide information on how the vaccines work in populations not included in the RCTs (e.g., nursing home residents), against new SARS-CoV-2 variants, with increasing time since vaccination, and in populations with increasing levels of prior infection. The goal of CDC's COVID-19 VE program is to provide timely and robust data to support ongoing policy decisions and implementation of vaccination and includes VE platforms to study the spectrum of illness, from infection to critical illness. Challenges to estimating VE include accurate ascertainment of vaccination history, outcome status, changing rates of prior infection, emergence of new variants, and appropriate interpretation of absolute and relative VE measures. CDC COVID-19 VE platforms have played a pivotal role in numerous vaccine policy decisions since 2021 and will continue to play a key role in future decisions as the vaccine program moves from an emergency response to a routine schedule.

Myopericarditis following COVID-19 vaccination in children: a systematic review and meta-analysis

INTRODUCTION

Myopericarditis is a rare but serious coronavirus disease 2019 (COVID-19) vaccine-related adverse event primarily affecting adolescents. Given recent approvals for childhood vaccination, we performed a meta-analysis investigating myopericarditis following messenger ribonucleic acid COVID-19 vaccination in children aged <19 years, focusing on its overall risk and high-risk subgroups.

METHODS

We searched MEDLINE via PubMed, Embase and Scopus from inception to 1 August 2022 for observational studies reporting myopericarditis in temporal relation to paediatric COVID-19 vaccination. We conducted random-effects meta-analyses (DerSimonian and Laird) on myopericarditis (primary outcome), myocarditis and pericarditis (secondary outcomes).

RESULTS

Of 2115 studies, 12 (59,229,160 doses) studies were included in our analysis. There were 19.8 (95% confidence interval [CI]: 10.4-37.6) myopericarditis cases reported per million doses in children, compared to 23.7 (95% CI: 12.2-46.1) cases in adults (eight studies, 376,899,888 doses; P = 0.70). Compared to the second dose (34.4, 95% CI: 15.2-77.8), the number of cases post-first dose was significantly lower (9.1, 95% CI: 4.4-18.8; P = 0.017), while the number of cases post-third dose was not higher than that of post-second dose (28.4, 95% CI: 10.4-61.8; P = 0.57, global P = 0.031). Males were at higher risk of myopericarditis (67.4, 95% CI: 36.5-124.5) than females (6.9, 95% CI: 3.1-15.3; P < 0.0001). Finally, the number of cases was higher (overall P < 0.0001) among children aged ≥12 years (39.9, 95% CI: 24.1-66.0) than among children aged <12 years (3.0, 95% CI: 2.3-3.9).

CONCLUSION

Our meta-analysis showed 19.8 cases of myopericarditis per million doses among children, not significantly different from that of adults. Higher risk subgroups included adolescents, males, and those receiving their second dose of vaccination.

Healthcare workers' perceptions and acceptance for COVID-19 vaccine for their children aged <18 years from the Region of Eastern Uttar Pradesh, India

Background

The coronavirus disease 2019 (COVID-19) vaccination program among adults in India is one of the highly successful vaccination drives globally, but the acceptance of the COVID-19 vaccine among parents for their children is largely unknown. As parents are primary decision-makers for their children, we aimed to assess parents' perceptions and acceptance for COVID-19 vaccination for children in India.

Aim

To assess parental perceptions and acceptance for COVID-19 vaccination for their children (aged <18 years).

Materials and Methods

A cross-sectional anonymous web-based survey was designed and conducted from November 1 to December 15, 2022. All the healthcare workers of a tertiary care institute in eastern Uttar Pradesh, having a child aged <18 years, constituted the study population and were invited. They were recruited through snowball sampling and were sent the study questionnaire in Google form through email and WhatsApp. Bivariate analysis was performed to determine the predictors of child vaccination acceptance among the parents.

Results

A total of 388 healthcare worker parents (HCWPs) having a child <18 years of age completed the survey. The mean age of the parents was 40.28 ± 11.34 years. The majority (96.9%) of them had already received the recommended two doses of the COVID-19 vaccine. Around 91% of the parents agreed that COVID-19 vaccines are important for children's health, whereas 89% agreed that COVID-19 vaccines are effective. A total of 356 (91.7%) parents were willing to vaccinate their children with a COVID-19 vaccine, of which 91.3% intended to do so as soon as possible. The factors significantly associated with the stated willingness for child vaccination among the participants were younger age (P = 0.008), female gender (P = 0000), currently married status (P = 0.00001), urban residence (P = 0.01), lower monthly income (P = 0.03), absence of any chronic illness (P = 0.0003), history of COVID-19 in the child (P = 0.004), and the child being up-to-date with the routine childhood vaccines (P = 0.01).

Conclusion

The HCWPs from eastern Uttar Pradesh, India, have a positive attitude and low vaccine hesitancy toward COVID-19 vaccination for children, with around 92% currently willing to vaccinate their children with COVID vaccine. Further longitudinal studies are required to assess the trend of parental acceptance of COVID vaccine.

The Spectrum of Postacute Sequelae of COVID-19 in Children: From MIS-C to Long COVID

The effects of SARS-CoV-2 infection on children continue to evolve following the onset of the COVID-19 pandemic. Although life-threatening multisystem inflammatory syndrome in children (MIS-C) has become rare, long-standing symptoms stemming from persistent immune activation beyond the resolution of acute SARS-CoV-2 infection contribute to major health sequelae and continue to pose an economic burden. Shared pathophysiologic mechanisms place MIS-C and long COVID within a vast spectrum of postinfectious conditions characterized by intestinal dysbiosis, increased gut permeability, and varying degrees of immune dysregulation. Insights obtained from MIS-C will help shape our understanding of the more indolent and prevalent postacute sequelae of COVID and ultimately guide efforts to improve diagnosis and management of postinfectious complications of SARS-CoV-2 infection in children.

Evaluating Immunologic and Illness Outcomes of SARS-CoV-2 Infection in Vaccinated and Unvaccinated Children Aged ≥ 5 Years, in a Multisite Longitudinal Cohort

Hybrid immunity, as a result of infection and vaccination to SARS-CoV-2, has been well studied in adults but limited evidence is available in children. We evaluated the antibody responses to primary SARS-CoV-2 infection among vaccinated and unvaccinated children aged ≥ 5 years.

METHODS

A longitudinal cohort study of children aged ≥ 5 was conducted during August 2021-August 2022, at sites in Arizona, Texas, Utah, and Florida. Children submitted weekly nasal swabs for PCR testing and provided sera 14-59 days after PCR-confirmed SARS-CoV-2 infection. Antibodies were measured by ELISA against the receptor-binding domain (RBD) and S2 domain of ancestral Spike (WA1), in addition to Omicron (BA.2) RBD, following infection in children, with and without prior monovalent ancestral mRNA COVID-19 vaccination.

RESULTS

Among the 257 participants aged 5 to 18 years, 166 (65%) had received at least two mRNA COVID-19 vaccine doses ≥ 14 days prior to infection. Of these, 53 occurred during Delta predominance, with 37 (70%) unvaccinated at the time of infection. The remaining 204 infections occurred during Omicron predominance, with 53 (26%) participants unvaccinated. After adjusting for weight, age, symptomatic infection, and gender, significantly higher mean RBD AUC values were observed among the vaccinated group compared to the unvaccinated group for both WA1 and Omicron (p < 0.0001). A smaller percentage of vaccinated children reported fever during illness, with 55 (33%) reporting fever compared to 44 (48%) unvaccinated children reporting fever (p = 0.021).

CONCLUSIONS

Children with vaccine-induced immunity at the time of SARS-CoV-2 infection had higher antibody levels during convalescence and experienced less fever compared to unvaccinated children during infection.

Multisystemic inflammatory syndrome in children and the BNT162b2 vaccine: a nationwide cohort study

Multisystemic inflammatory syndrome in children (MIS-C) is a rare, severe, post-infectious hyperinflammatory condition that occurs after COVID-19 infection. In this study, we aimed to demonstrate the risk reduction of MIS-C and severe MIS-C after Pfizer-BioNTech BNT162b2 mRNA COVID-19 vaccination. This nationwide cohort study included 526,685 PCR-confirmed COVID-19 cases (age < 19 years), of whom 14,118 were fully vaccinated prior to COVID-19 infection. MIS-C cases were collected from all hospitals in Israel from April 2020 through November 2021. The MIS-C rates were calculated among two COVID-19 populations: positive PCR confirmed cases and estimated COVID-19 cases (PCR confirmed and presumed). Vaccination status was determined from Ministry of Health (MoH) records. The MIS-C risk difference (RD) and 95% confidence intervals (95%CI) between vaccinated and unvaccinated patients are presented. Overall, 233 MIS-C cases under the age of 19 years were diagnosed and hospitalized in Israel during the study period. Among the estimated COVID-19 cases, MIS-C RD realistically ranged between 2.1 [95%CI 0.7-3.4] and 1.0 [95%CI 0.4-1.7] per 10,000 COVID-19 cases. For severe MIS-C, RD realistically ranged between 1.6 [95%CI 1.3-1.9] and 0.8 [95%CI 0.7-1.0], per 10,000 COVID-19 cases. Sensitivity analysis was performed on a wide range of presumed COVID-19 rates, demonstrating significant RD for each of these rates.

CONCLUSION

This research demonstrates that vaccinating children and adolescents against COVID-19 has reduced the risk of MIS-C during the study period.

WHAT IS KNOWN

• Most of the published literature regarding vaccine effectiveness is based on case-control studies, which are limited due to small sample sizes and the inability to fully estimate the risk of MIS-C among vaccinated and unvaccinated children and adolescents. • The known underestimation of COVID-19 diagnosis among children and adolescents is challenging, as they often have few to no symptoms.

WHAT IS NEW

• Significant risk difference was found in favor of the vaccinated group, even after including extreme assumptions regarding the underdiagnosed COVID-19 rate. • During this nationwide study period, it was found that vaccinating children and adolescents reduced the risk of MIS-C and its complications.

The complex landscape of immune dysregulation in multisystem inflammatory syndrome in children with COVID-19

The immune responses following SARS-CoV-2 infection in children are still under investigation. While coronavirus disease 2019 (COVID-19) is usually mild in the paediatric population, some children develop severe clinical manifestations or multisystem inflammatory syndrome in children (MIS-C) after infection. MIS-C, typically emerging 2-6 weeks after SARS-CoV-2 exposure, is characterized by a hyperinflammatory response affecting multiple organs. This review aims to explore the complex landscape of immune dysregulation in MIS-C, focusing on innate, T cell-, and B cell-mediated immunity, and discusses the role of SARS-CoV-2 spike protein as a superantigen in MIS-C pathophysiology. Understanding these mechanisms is crucial for improving the management and outcomes for affected children.

Engineering antigen-presenting cells for immunotherapy of autoimmunity

Autoimmune diseases are burdensome conditions that affect a significant fraction of the global population. The hallmark of autoimmune disease is a host's immune system being licensed to attack its tissues based on specific antigens. There are no cures for autoimmune diseases. The current clinical standard for treating autoimmune diseases is the administration of immunosuppressants, which weaken the immune system and reduce auto-inflammatory responses. However, people living with autoimmune diseases are subject to toxicity, fail to mount a sufficient immune response to protect against pathogens, and are more likely to develop infections. Therefore, there is a concerted effort to develop more effective means of targeting immunomodulatory therapies to antigen-presenting cells, which are involved in modulating the immune responses to specific antigens. In this review, we highlight approaches that are currently in development to target antigen-presenting cells and improve therapeutic outcomes in autoimmune diseases.

Clinical presentation, diagnosis and management of multisystem inflammatory syndrome in children (MIS-C): a systematic review

BACKGROUND

Knowledge about multisystem inflammatory syndrome in children (MIS-C) is evolving, and evidence-based standardised diagnostic and management protocols are lacking. Our review aims to summarise the clinical and diagnostic features, management strategies and outcomes of MIS-C and evaluate the variances in disease parameters and outcomes between high-income countries (HIC) and middle-income countries (MIC).

METHODS

We searched four databases from December 2019 to March 2023. Observational studies with a sample size of 10 or more patients were included. Mean and prevalence ratios for various variables were pooled by random effects model using R. A mixed generalised linear model was employed to account for the heterogeneity, and publication bias was assessed via funnel and Doi plots. The primary outcome was pooled mean mortality among patients with MIS-C. Subgroup analysis was conducted based on the income status of the country of study.

RESULTS

A total of 120 studies (20 881 cases) were included in the review. The most common clinical presentations were fever (99%; 95% CI 99.6% to 100%), gastrointestinal symptoms (76.7%; 95% CI 73.1% to 79.9%) and dermatological symptoms (63.3%; 95% CI 58.7% to 67.7%). Laboratory investigations suggested raised inflammatory, coagulation and cardiac markers. The most common management strategies were intravenous immunoglobulins (87.5%; 95% CI 82.9% to 91%) and steroids (74.7%; 95% CI 68.7% to 79.9%). Around 53.1% (95% CI 47.3% to 58.9%) required paediatric intensive care unit admissions, and overall mortality was 3.9% (95% CI 2.7% to 5.6%). Patients in MIC were younger, had a higher frequency of respiratory distress and evidence of cardiac dysfunction, with a longer hospital and intensive care unit stay and had a higher mortality rate than patients in HIC.

CONCLUSION

MIS-C is a severe multisystem disease with better mortality outcomes in HIC as compared with MIC. The findings emphasise the need for standardised protocols and further research to optimise patient care and address disparities between HIC and MIC.

PROSPERO REGISTRATION NUMBER

CRD42020195823.

COVID-19 and cardiac complications: Myocarditis and multisystem inflammatory syndrome in children

Coronavirus is an important pathogen causing disease in humans and animals. At the end of 2019, an investigation into an increase in pneumonia cases in Wuhan, Hubei Province, China, found that the cause was a new coronavirus. This disease, which spread rapidly across China and caused an outbreak worldwide, resulted in a pandemic. Although this virus has previously been referred to as 2019-nCoV, which causes coronavirus disease 2019 (COVID-19), later it was named severe acute respiratory syndrome coronavirus 2. Children were usually asymptomatic and rarely severely affected. In April 2020, reports from the United Kingdom indicated that children may have Kawasaki disease or a clinical condition similar to toxic shock syndrome. This clinical picture was later defined as multisystem inflammatory syndrome in children. Since then, similarly affected children as well as cases with other cardiac complications have been reported in other parts of the world. In this review, we aimed to evaluate COVID-19 in terms of cardiac involvement by reviewing the literature.

Efficacy, Effectiveness, and Safety of COVID-19 Vaccine Compared to Placebo in Preventing COVID-19 Infection among 12-17 Years Old: A Systematic Review

Objectives

The World Health Organization recently revised their recommendations and considered healthy children and adolescents as low priority group for COVID-19 vaccine. This review comprehensively assessed existing clinical evidence on COVID-19 vaccine in 12-17 years old.

Methods

Included in this review were any type of study that investigated the efficacy, immunogenicity, safety, and effectiveness of COVID-19 vaccine on protection against SARS-COV-2 infection in 12-17 years old. Various electronic databases were searched up to March 15, 2023. Studies were screened, data extracted, risk of bias appraised, and certainty of evidence was judged using GRADE. Review Manager 5.4 was used to estimate pooled effects. Difference between the two groups was described as mean difference for continuous variables and as relative risk or odds ratio for categorical variables.

Results

There were six randomized controlled trials and 16 effectiveness studies (8 cohorts and 8 case control). Low certainty evidence showed that BNT162b2 (Pfizer) was effective, immunogenic, and safe in healthy adolescents. There were 15 effectiveness studies on BNT162b2 (Pfizer) in healthy adolescent and one on immunocompromised patients. It was protective against infection with any of the variants, with higher protection against Delta than Omicron. BNT162b2 is protective against hospitalization and emergency and urgent care (high certainty); and critical care and MIS-C (low). Very low certainty evidence noted that BNT 162b2 was also immunogenic in 12-21 years old with rheumatic diseases while on immunomodulatory treatment but with possible increased exacerbation of illness. Low certainty evidence demonstrated that mRNA-1273 (Moderna) was effective, immunogenic, and safe. Low to very low certainty evidence were noted on the safety and immunogenicity of two vector base vaccines (ChAdOx1-19 and Ad5 vector COVID vaccine) and two inactivated vaccines (CoronaVac and BBIBP CorV).

CONCLUSION

There is presently low certainty evidence on the use of RNA vaccines in 12-17 years old. The recommendation on its use is weak. There is presently insufficient evidence for the use of inactivated and vector-based COVID-19 vaccines. Different countries should consider whether to vaccinate healthy adolescent without comprising the other recommended immunization and health priorities that are crucial for this age group. Other factors including cost-effectiveness of vaccination and disease burden should be accounted.

Effectiveness of COVID-19 vaccination against school absenteeism in children and adolescents hospitalized with COVID-19

BACKGROUND

COVID-19 vaccination has been recommended for children to protect them and to enable in-person educational and social activities.

METHODS

We estimated COVID-19 vaccination effectiveness (VE) against school absenteeism in children 5-17 years old hospitalized from September 1, 2021 through May 31, 2023. Full vaccination was defined as two vaccine doses.

RESULTS

We studied 231 children admitted to hospital with COVID-19, including 206 (89.2 %) unvaccinated/partially vaccinated and 25 (10.8 %) fully vaccinated. Unvaccinated/partially vaccinated children were absent from school for longer periods compared to fully vaccinated children (median absence: 14 versus 10 days; p-value = 0.05). Multivariable regression showed that full COVID-19 vaccination was associated with fewer days of absence compared to no/partial vaccination on average (adjusted relative risk: 0.77; 95 % CI: 0.61 to 0.98). COVID-19 VE was 50.7 % (95 % CI: -11.3 % to 78.2 %) for school absenteeism above the median duration of absenteeism.

CONCLUSIONS

Full COVID-19 vaccination conferred protection against school absenteeism in hospitalized school-aged children with COVID-19.

Multisystem inflammatory syndrome in children (MIS-C): A nationwide collaborative study in the Greek population

Multisystem inflammatory syndrome in children (MIS-C) is a rare but severe hyperinflammatory condition that may occur following SARS-CoV-2 infection. This retrospective, descriptive study of children hospitalized with multisystem inflammatory syndrome in children (MIS-C) in 12 tertiary care centers from 3/11/2020 to 12/31/2021. Demographics, clinical and laboratory characteristics, treatment and outcomes are described. Among 145 patients (95 males, median age 8.2 years) included, 123 met the WHO criteria for MIS-C, while 112 (77%) had serological evidence of SARS-CoV-2 infection. Fever was present in 99%, gastrointestinal symptoms in 77%, mucocutaneous involvement in 68% and respiratory symptoms in 28%. Fifty-five patients (38%) developed myocarditis, 29 (20%) pericarditis and 19 (13%) coronary aneurysms. Among the above cases 11/55 (20%), 1/29 (3.4%) and 5/19 (26.3%), respectively, cardiac complications had not fully resolved at discharge. Underlying comorbidities were reported in 18%. Median CRP value was 155 mg/l, ferritin 535 ng/ml, PCT 1.6 ng/ml and WBC 14.2 × 109/mm3. Most patients had elevated troponin (41.3%) and/or NT-pro-BNP (49.6%). Intravenous immunoglobulin plus corticosteroids were used in 117/145 (80.6%), monotherapy with IVIG alone in 13/145 (8.9%) and with corticosteroids alone in 2/145 (1.3%). Anti-IL1 treatment was added in 15 patients (10.3%). Thirty-three patients (23%) were admitted to the PICU, 14% developed shock and 1 required ECMO. Mortality rate was 0.68%. The incidence of MIS-C was estimated at 0.69/1000 SARS-CoV-2 infections. Patients who presented with shock had higher levels of NT-pro-BNP compared to those who did not (p < 0.001). Acute kidney injury and/or myocarditis were associated with higher risk of developing shock.

CONCLUSION

MIS-C is a novel, infrequent but serious disease entity. Cardiac manifestations included myocarditis and pericarditis, which resolved in most patients before discharge. Timely initiation of immunomodulatory therapy was shown to be effective. NT-pro-BNP levels may provide a better prediction and monitoring of the disease course. Further research is required to elucidate the pathogenesis, risk factors and optimal management, and long-term outcomes of this clinical entity.

WHAT IS KNOWN

• MIS-C is an infrequent but serious disease entity. • Patients with MIS-C present with multi-organ dysfunction, primarily involving the gastrointestinal and cardiovascular systems.

WHAT IS NEW

• NT-pro-BNP levels may provide a better prediction and monitoring of the disease course. • Acute kidney injury and/or myocarditis were associated with higher risk of developing shock.

COVID-19 Vaccine Acceptance Among Parents of Children With Multisystem Inflammatory Syndrome in Children

Data on COVID-19 vaccine acceptability among parents of children with multisystem inflammatory syndrome (MIS-C) are limited. In this cohort of children with MIS-C, enrolled in the Swissped RECOVERY trial (NCT04826588), comparing intravenous immunoglobulins or methylprednisolone, who, in accordance with Swiss guidelines, were recommended for SARS-CoV-2 vaccination, 65% (73/112) of parents reported being vaccinated against SARS-CoV-2 before the MIS-C, while 70% were vaccinated after the MIS-C episode of their child. None of the children were vaccinated before the occurrence of the MIS-C, and only 9% (5/56) received the COVID-19 vaccine after the MIS-C. The predominant barriers to COVID-19 vaccination were concerns over potential side effects and insufficient support from their doctors. This emphasizes the crucial role of health care providers in promoting COVID-19 vaccination among children.

Evolution of Cardiovascular Findings in Multisystem Inflammatory Syndrome in Children (MIS-C) Across COVID-19 Variants: Common Trends and Unusual Presentations

Multisystem inflammatory syndrome in children (MIS-C) is a rare condition following COVID-19 infection. Cardiac involvement is common and includes left ventricular systolic dysfunction, cardiac marker elevation, electrocardiogram (ECG) changes, and coronary artery dilation. This single-center retrospective cohort study compares cardiovascular disease between three major SARS-CoV-2 variants and describes the evolution of findings in medium-term follow-up. Of 69 total children (mean age 9.2 years, 58% male), 60 (87%) had cardiovascular involvement with the most common features being troponin elevation in 33 (47%) and left ventricular dysfunction in 22 (32%). Based on presumed infection timing, 61 patients were sorted into variant cohorts of Alpha, Delta, and Omicron. Hospitalization was longer for the Delta group (7.7 days) vs Alpha (5.1 days, p = 0.0065) and Omicron (4.9 days, p = 0.012). Troponin elevation was more common in Delta compared to Alpha (13/20 vs 7/25, p = 0.18), and cumulative evidence of cardiac injury (echocardiographic abnormality and/or troponin elevation) was more common in Delta (17/20) compared with Alpha (12/25, p = 0.013) or Omicron (8/16, p = 0.034). Forty-nine (77%) of the original cohort (n = 69) had no cardiac symptoms or findings beyond 3 months post-hospitalization. Cardiac MRI was performed in 28 patients (between 3 and 6 months post-hospitalization) and was normal in 25 patients (89%). The differences in the variant cohorts may be due to alteration of the immune landscape with higher severity of COVID-19 infection. Despite overall reassuring cardiac outcomes, it is important to note the variability of presentation and remain vigilant with future variants.

Factors associated with COVID-19 vaccination in young children

OBJECTIVE

To examine factors associated with COVID-19 vaccination (time to vaccination and vaccination status) among healthy young children participating in primary healthcare.

METHODS

A cohort study was conducted between November 2021 and September 2022 through the TARGet Kids! primary care research network in Toronto, Canada. Sociodemographic information, child and parent health characteristics, parental vaccine beliefs and child COVID-19 vaccine uptake were collected through parent-reported questionnaires. The primary outcome was time to child COVID-19 vaccination, measured as the time between vaccine availability date and parent-reported child COVID-19 vaccination date. Interval-censored proportional hazard models were used.

RESULTS

A total of 267 children age 0 to 13 years were included. The mean child age was 7.6 years, 52.8% (n = 141) were male, 66.5% (n = 141) had mothers of European ethnicity (with missingness), and 68.2% (n = 182) of the children were vaccinated. All parents of vaccinated children had received the COVID-19 vaccination themselves. The rate of vaccination for children was 2% higher with each one-month increase in child age (adjusted HR = 1.02, 95%CI = 1.01-1.03, p < 0.001). Compared to children whose parents had uncertain beliefs, those whose parents had positive beliefs about the importance and safety of COVID-19 vaccination for their children had higher rates of vaccination (adjusted HR = 8.29, 95%CI = 4.25-16.17, p < 0.001; adjusted HR = 5.09, 95%CI = 3.17-8.17, p < 0.001).

CONCLUSION

Older child age, parental COVID-19 vaccination, and positive parental beliefs about COVID-19 vaccination were statistically significantly associated with COVID-19 vaccination among healthy young children. Our findings may help to inform policies, practices, and research which aim to strengthen parental vaccine confidence and promote child COVID-19 vaccination.

COVID-19-Related Multi-systemic Inflammatory Syndrome in Children (MIS-C)

Multisystem inflammatory syndrome in children (MIS-C) is a severe complication of SARS-CoV-2 infections in children. This syndrome manifests about a month after the initial viral infection and is characterized by fever, multiorgan dysfunction, and systemic inflammation. This chapter will review the emergence, epidemiology, clinical characteristics, diagnosis, pathophysiology, immunomodulatory treatment, prognosis, outcomes, and prevention of MIS-C. While the pathophysiology of MIS-C remains to be defined, it is a post-infection, hyperinflammatory syndrome of childhood with elevated inflammatory cytokines.

A Case With Typical Clinical Manifestations of Kawasaki Disease and Multisystem Inflammatory Syndrome in Children Temporally Associated With SARS-CoV-2 Infection

Whether Kawasaki disease (KD) and multisystem inflammatory syndrome in children (MIS-C) temporally associated with SARS-CoV-2 infection are two distinct syndromes or part of the same spectrum is not fully understood. In this report, we present the case of a five-year-old boy who fully satisfied the diagnostic criteria for both KD and MIS-C associated with SARS-CoV-2 infection. He tested positive for SARS-CoV-2 on an oropharyngeal swab antigen test approximately four weeks before the onset of symptoms. He had severe abdominal pain. Abdominal ultrasound showed ascites. He improved with initial (2 g/kg) and additional (1 g/kg) intravenous immunoglobulin (IVIG) therapy and intravenous methylprednisolone (initial dose, 2 mg/kg/day). Our case may lead to clarification of the pathogenesis of both diseases. Additionally, the recent history of SARS-CoV-2 infection for children with prolonged fever and no clear focus of infection should be checked, and, if present, clinicians should consider MIS-C temporally associated with SARS-CoV-2 infection. IVIG therapy is important for children with MIS-C who meet the diagnostic criteria for KD, even if diagnosed with MIS-C.

Clinical course and follow-up of pediatric patients with COVID-19 vaccine-associated myocarditis compared to non-vaccine-associated myocarditis within the prospective multicenter registry-"MYKKE"

BACKGROUND

Since the onset of widespread COVID-19 vaccination, increased incidence of COVID-19 vaccine-associated myocarditis (VA-myocarditis) has been noted, particularly in male adolescents.

METHODS

Patients <18 years with suspected myocarditis following COVID-19 vaccination within 21 days were enrolled in the PedMYCVAC cohort, a substudy within the prospective multicenter registry for pediatric myocarditis "MYKKE." Clinical data at initial admission, 3- and 9-months follow-up were monitored and compared to pediatric patients with confirmed non-vaccine-associated myocarditis (NVA-myocarditis) adjusting for various baseline characteristics.

RESULTS

From July 2021 to December 2022, 56 patients with VA-myocarditis across 15 centers were enrolled (median age 16.3 years, 91% male). Initially, 11 patients (20%) had mildly reduced left ventricular ejection fraction (LVEF; 45%-54%). No incidents of severe heart failure, transplantation or death were observed. Of 49 patients at 3-months follow-up (median (IQR) 94 (63-118) days), residual symptoms were registered in 14 patients (29%), most commonly atypical intermittent chest pain and fatigue. Diagnostic abnormalities remained in 23 patients (47%). Of 21 patients at 9-months follow-up (259 (218-319) days), all were free of symptoms and diagnostic abnormalities remained in 9 patients (43%). These residuals were mostly residual late gadolinium enhancement in magnetic resonance imaging. Patients with NVA-myocarditis (n=108) more often had symptoms of heart failure (P = .003), arrhythmias (P = .031), left ventricular dilatation (P = .045), lower LVEF (P < .001) and major cardiac adverse events (P = .102).

CONCLUSIONS

Course of COVID-19 vaccine-associated myocarditis in pediatric patients seems to be mild and differs from non-vaccine-associated myocarditis. Due to a considerable number of residual symptoms and diagnostic abnormalities at follow-up, further studies are needed to define its long-term implications.

Prognostic factors for multisystem inflammatory syndrome in children: A systematic review and meta-analysis

AIM

Multisystem inflammatory syndrome in children (MIS-C) is a novel condition that can occur post-SARS-CoV-2 infection in children and adolescents. There is a paucity of evidence on the prognostic factors associated with MIS-C. The aim of this systematic review and meta-analysis was to summarise the prognostic factors for MIS-C development.

METHODS

Five databases were systematically searched from January 2020 to May 2023 for studies reporting on prognostic factors for MIS-C using multivariable regression models. Random-effects meta-analyses were conducted to pool odds ratios for each prognostic factor. Risk of bias was rated using QUIPS and the GRADE framework was used to assess the certainty of evidence for each unique factor.

RESULTS

Twelve observational studies (N = 18 024) were included, and 13 unique prognostic factors were amenable to meta-analysis. With moderate certainty, age <12 years, male sex and Black race probably increase the risk of MIS-C. Malignancy and underlying respiratory disease probably decrease the risk of MIS-C. Low-certainty evidence suggests that Asian race may increase the risk of MIS-C, and comorbidity may decrease the risk of MIS-C.

CONCLUSION

Current literature presents several prognostic factors related to MIS-C following SARS-CoV-2 infection. Further research is necessary to elucidate the pathophysiologic mechanisms related to MIS-C.

COVID-19 Vaccines in Children

The COVID-19 pandemic has left an indelible mark on global health, affecting individuals of all ages across diverse communities. While the virus has predominantly been associated with severe outcomes in adults, its impact on children has garnered increasing attention. Today, three COVID-19 vaccines are available for use in the U.S. and recommended by the Advisory Committee on Immunization Practices (ACIP). As of September 2023, ongoing genomic surveillance identified SARS-CoV-2 XBB sublineages as the most common circulating SARS-CoV-2 variants, constituting over 99% of sequenced SARS-CoV-2 specimens in the US. Recently, recommendations for COVID-19 vaccination were updated accordingly to the 2023-2024 Omicron-XBB.1.5-adapted monovalent COVID-19 vaccine to provide heightened protection against currently circulating SARS-CoV-2 XBB-sublineage variants. COVID-19 vaccines have proven to be safe, efficacious, and effective at protecting against COVID-19 and preventing severe illness in children and adolescents.

The protective effects of pediatric vaccination on multisystem inflammatory syndrome in children stratified by vaccine status, types and virus variants

BACKGROUND

Few studies highlight the stratification of COVID-19 vaccine effectiveness on MIS-C according to vaccine status, types and SARS-COV-2 variants.

METHODS

A web-based analysis was conducted through searches of PubMed, Web of Science and Medline databases from January 1, 2020, to May 16, 2023. The search terms used were (multisystem inflammatory syndrome in children OR MIS-C OR PIMS OR PIMS-TS) AND (COVID-19 OR SARS-CoV-2) AND (vaccine OR vaccination) AND (children OR adolescents OR pediatric).

RESULTS

6701 children from 13 studies met the MIS-C definition. 92.1 % (1332/1446) of MIS-C cases were unvaccinated, whereas partial vaccination and full vaccination were 3.7 % (54/1446) and 4.2 % (60/1446)respectively. In the two studies encompassing 41 vaccinated MIS-C cases, 34 (82.9 %) received BNT162b2, 2 (4.9 %) received mRNA-1273, 4 (9.8 %) received Sinovac vaccine, and only one received a heterologous primary-boost regimen. Among 838 vaccinated MIS-C cases with different SARS-COV-2 variants, 23（2.8 %） were infected by the Wild-type, 80（9.5 %） by the Alpha variant, 521（62.2 %） by the Delta variant, and 214（25.5 %） by the Omicron variant. A significant difference was observed in vaccination rates among MIS-C cases across different variant pandemics (χ2 = 37.79, P < 0.001). The highest vaccination rate (26.3 %) occurred in the Alpha predominant period, thereafter dropped to 5.0 % in the Delta predominant period, and then increased to 12.6 % in the Omicron predominant period.

CONCLUSIONS

Heterologous vaccination might provide a slightly more protective effect than homologous manner for MIS-C. As the virus mutates over time, its pathogenicity to MIS-C degrades among vaccinated individuals.

Clinical Syndromes Related to SARS-CoV-2 Infection and Vaccination in Pediatric Age: A Narrative Review

This narrative review aims to report the main clinical manifestations, therapeutic strategies, outcomes, and complications of acute SARS-CoV-2 infection in childhood and to summarize the data relating the SARS-CoV-2 vaccination efficacy and safety in pediatric age. SARS-CoV-2 infection mostly occurs asymptomatically in the pediatric population, while multisystem inflammatory syndrome in children (MIS-C) represents the most severe coronavirus disease 2019 (COVID-19)-related illness, a life-threatening event with a high morbidity rate. After the development of SARS-CoV-2 vaccines and their subsequent approval in children, the rate of infection as well as the number of its related complications have shown a drastic decrease. Fully vaccinated children are protected from the risk of developing a severe disease and a similar protective role has been observed in the reduction of complications, in particular MIS-C. However, long-lasting immunity has not been demonstrated, booster doses have been required, and reinfection has been observed. With regards to vaccine safety, adverse events were generally mild to moderate in all age groups: local adverse events were the most commonly reported. Nevertheless, a potential association between SARS-CoV-2 vaccine and the subsequent development of inflammatory manifestations has been suggested. Myocarditis has rarely been observed following vaccination; it appeared to be more frequent among adolescent males with a mild clinical course leading to a complete recovery. SARS-CoV-2 vaccine-related MIS-C cases have been described, although a univocal definition and an exact time interval with respect to vaccination has not been reported, thus not establishing a direct causal link. Current evidence about COVID-19 vaccination in children and adolescents suggest that benefits outweigh potential risks. Long-term data collection of the post-authorization safety surveillance programs will better define the real incidence of SARS-CoV-2 vaccine-related complications in the pediatric population.

Demographic, clinical and laboratory differences between paediatric acute COVID-19 and PIMS-TS-results from a single centre study in the UK

Background

Paediatric symptomatic SARS-CoV-2 infections associate with two presentations, acute COVID-19 and paediatric inflammatory multisystem syndrome temporally associated with SARS-CoV-2 (PIMS-TS). Phenotypic comparisons, and reports on predictive markers for disease courses are sparse and preliminary.

Methods

A chart review of COVID-19 and PIMS-TS patients (≤19 years) admitted to Alder Hey Children's NHS Foundation Trust, a tertiary centre in the North-West of England, was performed (02/2020-09/2022).

Results

A total of 161 symptomatic COVID-19 and 50 PIMS-TS patients were included. Peaks in admissions of patients with PIMS-TS occurred approximately 4 weeks after those for acute COVID-19. The incidence of in-patients with PIMS-TS reduced over time, and there were no admissions after February 2022. When compared to acute COVID-19, PIMS-TS patients were older (median: 10.3 years vs. 2.03 years; p < 0.001). There were no differences in gender distribution, but minority ethnicities were over-represented among PIMS-TS patients. Regional ethnic distribution was reflected among acute COVID-19 patients (66% vs. 84.5% White Caucasian, p = 0.01). Pre-existing comorbidities were more common among acute COVID-19 patients (54.7% vs. 8%, p < 0.001). PIMS-TS patients more commonly presented with abdominal symptoms (92% vs. 50.3%), neurological symptoms (28% vs. 10.6%) and skin rashes (72% vs. 16.8%), (p ≤ 0.01) when compared with acute COVID-19, where respiratory symptoms were more common (51.6% vs. 32%, p = 0.016). PIMS-TS more frequently required intensive care admission (64% vs. 16.8%), and inotropic support (64% vs. 9.3%) (all p < 0.05). More deaths occurred among acute COVID-19 patients [0 vs. 7 (4.4%)], with 5/7 (71%) in the context of pre-existing comorbidities. When compared to acute COVID-19, PIMS-TS patients exhibited more lymphopenia and thrombocytopenia, a more pronounced acute phase reaction, and more hyponatraemia (p < 0.05). Partial least square discriminant analysis of routine laboratory parameters allowed (incomplete) separation of patients at diagnosis, and variable importance projection (VIP) scoring revealed elevated CRP and low platelets as the most discriminatory parameters.

Conclusion

Admissions for PIMS-TS reduced with increasing seroconversion rates in the region. Young age and pre-existing comorbidities associate with hospital admission for acute COVID-19. While PIMS-TS may present more acutely with increased need for intensive care, acute COVID-19 had an increased risk of mortality in this cohort.

Ischemic Stroke in the Course of COVID-19 in a 16-Year-Old Boy

The SARS-CoV-2 virus that causes COVID-19 disease is still evolving and, despite the end of the acute phase of the pandemic, still poses a risk to public health. One of the very rare complications, occurring in less than 1% of children, is multisystem inflammatory syndrome in children (MISC). Due to the risk of thromboembolic complications as well as cardiac problems, MISC carries a number of life-threatening complications. We report a case of a 16-year-old boy who was hospitalized due to general weakness, fever, conjunctivitis, vomiting and diarrhoea. In view of the mother's positive result of the SARS-CoV-2 test, the teenager underwent numerous laboratory tests. Taking into account the critical condition of the patient, anticoagulant and antipyretic treatment, steroids and IVIG were added. During hospitalisation, alarming symptoms occurred, including dysarthria, drooping corner of the mouth and muscle weakness on the right side. The magnetic resonance imaging showed changes characteristic of ischemic stroke. Further studies are needed to assess possible thrombotic complications in children after SARS-CoV-2 infection, and specialists should be more vigilant in paediatric patients presenting with such symptoms.

Multisystem Inflammatory Syndrome (MIS) following SARS-CoV-2 vaccinations; a systematic review

BACKGROUND

Although SARS-CoV-2 vaccines are generally safe, there are growing concerns about their link to a potentially life-threatening multi-system inflammatory syndrome following vaccination (MIS-V). We conducted this systematic review to elucidate the prevalence of MIS, severity, treatment, and outcomes following SARS-CoV-2 vaccination.

METHODS

We searched PubMed, Scopus, ScienceDirect, Google Scholar, Virtual Health Library (VHL), Cochrane Library, and Web of Science databases for articles and case reports about MIS-V. We performed a qualitative analysis of individual cases from the included studies.

RESULTS

Of the 1366 studies identified by database search, we retrieved twenty-six case reports and two cohort studies. We analyzed the data of 37 individual cases extracted from 27 articles. The average age of the cases included in this review was 18 (1-67) years, with the most being male (M: F 3.1:1). Of the 37 included cases, the cardiovascular system was the most affected system by MIS (36, 97.3%), followed by the gastrointestinal tract (32, 86.5%).

CONCLUSION

MIS after SARS-CoV-2 vaccinations can be fatal, but the incidence is low. Prompt recognition of MIS and ruling out the mimickers are critical in the patient's early recovery.

Epidemiology and Severity of Illness of MIS-C and Kawasaki Disease During the COVID-19 Pandemic

BACKGROUND AND OBJECTIVES

Multisystem inflammatory syndrome in children (MIS-C) is a novel, severe condition following severe acute respiratory syndrome coronavirus 2 infection. Large epidemiologic studies comparing MIS-C to Kawasaki disease (KD) and evaluating the evolving epidemiology of MIS-C over time are lacking. We sought to understand the illness severity of MIS-C compared with KD and evaluate changes in MIS-C illness severity over time during the coronavirus disease 2019 pandemic compared with KD.

METHODS

We included hospitalizations of children with MIS-C and KD from April 2020 to May 2022 from the Pediatric Health Information System administrative database. Our primary outcome measure was the presence of shock, defined as the use of vasoactive/inotropic cardiac support or extracorporeal membrane oxygenation. We examined the volume of MIS-C and KD hospitalizations and the proportion of hospitalizations with shock over time using 2-week intervals. We compared the proportion of hospitalizations with shock in MIS-C and KD patients over time using generalized estimating equations adjusting for hospital clustering and age, with time as a fixed effect.

RESULTS

We identified 4868 hospitalizations for MIS-C and 2387 hospitalizations for KD. There was a higher proportion of hospitalizations with shock in MIS-C compared with KD (38.7% vs 5.1%). In our models with time as a fixed effect, we observed a significant decrease in the odds of shock over time in MIS-C patients (odds ratio 0.98, P < .001) but not in KD patients (odds ratio 1.00, P = .062).

CONCLUSIONS

We provide further evidence that MIS-C is a distinct condition from KD. MIS-C was a source of lower morbidity as the pandemic progressed.

A Review of the Data Supporting Use of COVID-19 Vaccinations in the Pediatric Population

OBJECTIVE

The objective of this study was to review the effectiveness and safety of COVID-19 vaccinations in the pediatric population.

DATA SOURCES

PubMed/Medline (September 2020 to December 2022), the Centers for Disease Control and Prevention, and Food and Drug Administration (FDA) websites.

STUDY SELECTION AND DATA EXTRACTION

Publications regarding the safety and efficacy of COVID-19 vaccinations in children were included.

DATA SYNTHESIS

Vaccines authorized for use in children include two monovalent mRNA vaccines (≥6 months old) and one monovalent protein subunit adjuvant vaccine (adolescents only). Omicron-specific mRNA bivalent boosters are authorized for children ≥6 months old. Studies after monovalent vaccine authorization illustrated efficacy in children >5 to 6 years of age, specifically decreased severe COVID-19 (including mortality) and multisystem inflammatory response syndrome occurrence (including during Omicron predominance). Available data for children <5 to 6 years suggests efficacy, although data are limited. Monovalent vaccine efficacy against Omicron infections may wane as early as 2 months, but protection against severe disease complications may last longer, and bivalent Omicron boosters are anticipated to increase effectiveness. Myocarditis/pericarditis is a safety concern associated with the COVID-19 vaccinations but occurs less frequently then COVID-19 complications and thus the benefit outweighs the risks.

RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE

Caregivers seek information from health care professionals regarding vaccine safety and efficacy. Pharmacists can use the objective information in this review to educate caregivers and effectively administer COVID-19 vaccines to patients.

CONCLUSIONS

There is sufficient and continually growing safety and efficacy data available to recommend COVID-19 vaccinations for children ≥6 months of age.

Multisystem inflammatory syndrome in children (MIS-C): Implications for long COVID

The COVID-19 pandemic caused by the coronavirus 2 of the severe acute respiratory syndrome (SARS-CoV-2) has significantly affected people around the world, leading to substantial morbidity and mortality. Although the pandemic has affected people of all ages, there is increasing evidence that children are less susceptible to SARS-CoV-2 infection and are more likely to experience milder symptoms than adults. However, children with COVID-19 can still develop serious complications, such as multisystem inflammatory syndrome in children (MIS-C). This narrative review of the literature provides an overview of the epidemiology and immune pathology of SARS-CoV-2 infection and MIS-C in children. The review also examines the genetics of COVID-19 and MIS-C in children, including the genetic factors that can influence the susceptibility and severity of the diseases and their implications for personalized medicine and vaccination strategies. By examining current evidence and insights from the literature, this review aims to contribute to the development of effective prevention and treatment strategies for COVID-19, MIS-C, and long COVID syndromes in children.

Awareness of Multisystem Inflammatory Syndrome in Children Among US Parents: A Cross-Sectional Survey

Background

Little is known about parental awareness of multisystem inflammatory syndrome in children (MIS-C), a rare but severe sequela of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection.

Methods

Via a nationally representative, cross-sectional survey of US parents conducted via Ipsos KnowledgePanel from October to November 2021, we used bivariate and multivariable analyses to describe and identify demographic variables associated with parental knowledge of and attitudes toward MIS-C and to examine associations with perceived coronavirus disease 2019 (COVID-19) severity and susceptibility.

Results

Response rate was 64.2% (3230/5034). Thirty-two percent of respondents had heard of MIS-C. After adjustment, higher educational level (compared to high school degree; some college: odds ratio [OR], 2.00 [95% confidence interval {CI}, 1.44-2.77]; bachelor's degree or higher: OR, 3.14 [95% CI, 2.26-4.35]), being a healthcare worker (OR, 1.82 [95% CI, 1.37-2.42]), having a child with a chronic medical condition (OR, 1.62 [95% CI, 1.22-2.14]), and experience with more severe COVID-19 (OR, 1.46 [95% CI, 1.14-1.86]) were associated with MIS-C awareness. Respondents with a child aged 12-17 years were less likely to be aware of MIS-C compared to those without (OR, 0.78 [95% CI, .63-.96]), as were male respondents (OR, 0.56 [95% CI, .46-.69]) and respondents aged 18-34 years (OR, 0.72 [95% CI, .54-.94]) compared to those aged 35-44 years. Awareness of MIS-C was associated with higher perceived COVID-19 severity and susceptibility (regression coefficients, 0.18 [95% CI, .10-.25], P < .001; 0.19 [95% CI, .11-.28], P < .001, respectively).

Conclusions

This survey highlights the need to increase parental awareness of MIS-C. Future studies should explore how education regarding MIS-C as a complication of SARS-CoV-2 infection could improve understanding of pediatric disease severity and susceptibility.

COVID Vaccination as a Strategy for Cardiovascular Disease Prevention

PURPOSE OF REVIEW

Cardiovascular (CV) disease is a known complication of SARS-CoV-2 infection. A clear benefit of COVID-19 vaccination is a reduction mortality; however, COVID-19 vaccination may also prevent cardiovascular disease (CVD). We aim to describe CV pathology associated with SARS-CoV-2 infection and describe how COVID-19 vaccination is a strategy for CVD prevention.

RECENT FINDINGS

The risks and benefits of COVID-19 vaccination have been widely studied. Analysis of individuals with and without pre-existing CVD has shown that COVID-19 vaccination can prevent morbidity associated with SARS-CoV-2 infection and reduce mortality. COVID-19 vaccination is effective in preventing myocardial infarction, cerebrovascular events, myopericarditis, and long COVID, all associated with CVD risk factors. Vaccination reduces mortality in patients with pre-existing CVD. Further study investigating ideal vaccination schedules for individuals with CVD should be undertaken to protect this vulnerable group and address new risks from variants of concern.

Long-term humoral signatures following acute pediatric COVID-19 and Multisystem Inflammatory Syndrome in Children

BACKGROUND

Although most children experience mild symptoms during acute SARS-CoV-2 infection, some develop the severe post-COVID-19 complication, Multisystem Inflammatory Syndrome in Children (MIS-C). While acute presentations of COVID-19 and MIS-C have been well immunophenotyped, little is known about the lasting immune profile in children after acute illness.

METHODS

Children 2 months-20 years of age presenting with either acute COVID-19 (n = 9) or MIS-C (n = 12) were enrolled in a Pediatric COVID-19 Biorepository at a single medical center. We deeply profiled humoral immune responses and circulating cytokines following pediatric COVID-19 and MIS-C.

RESULTS

Twenty-one children and young adults provided blood samples at both acute presentation and 6-month follow-up (mean: 6.5 months; standard deviation: 1.77 months). Pro-inflammatory cytokine elevations resolved after both acute COVID-19 and MIS-C. Humoral profiles continue to mature after acute COVID-19, displaying decreasing IgM and increasing IgG over time, as well as stronger effector functions, including antibody-dependent monocyte activation. In contrast, MIS-C immune signatures, especially anti-Spike IgG1, diminished over time.

CONCLUSIONS

Here, we show the mature immune signature after pediatric COVID-19 and MIS-C, displaying resolving inflammation with recalibration of the humoral responses. These humoral profiles highlight immune activation and vulnerabilities over time in these pediatric post-infectious cohorts.

IMPACT

The pediatric immune profile matures after both COVID-19 and MIS-C, suggesting a diversified anti-SARS-CoV-2 antibody response after resolution of acute illness. While pro-inflammatory cytokine responses resolve in the months following acute infection in both conditions, antibody-activated responses remain relatively heightened in convalescent COVID-19. These data may inform long-term immunoprotection from reinfection in children with past SARS-CoV-2 infections or MIS-C.

Clinical phenotypes and outcomes in children with multisystem inflammatory syndrome across SARS-CoV-2 variant eras: a multinational study from the 4CE consortium

Background

Multisystem inflammatory syndrome in children (MIS-C) is a severe complication of SARS-CoV-2 infection. It remains unclear how MIS-C phenotypes vary across SARS-CoV-2 variants. We aimed to investigate clinical characteristics and outcomes of MIS-C across SARS-CoV-2 eras.

Methods

We performed a multicentre observational retrospective study including seven paediatric hospitals in four countries (France, Spain, U.K., and U.S.). All consecutive confirmed patients with MIS-C hospitalised between February 1st, 2020, and May 31st, 2022, were included. Electronic Health Records (EHR) data were used to calculate pooled risk differences (RD) and effect sizes (ES) at site level, using Alpha as reference. Meta-analysis was used to pool data across sites.

Findings

Of 598 patients with MIS-C (61% male, 39% female; mean age 9.7 years [SD 4.5]), 383 (64%) were admitted in the Alpha era, 111 (19%) in the Delta era, and 104 (17%) in the Omicron era. Compared with patients admitted in the Alpha era, those admitted in the Delta era were younger (ES -1.18 years [95% CI -2.05, -0.32]), had fewer respiratory symptoms (RD -0.15 [95% CI -0.33, -0.04]), less frequent non-cardiogenic shock or systemic inflammatory response syndrome (SIRS) (RD -0.35 [95% CI -0.64, -0.07]), lower lymphocyte count (ES -0.16 × 109/uL [95% CI -0.30, -0.01]), lower C-reactive protein (ES -28.5 mg/L [95% CI -46.3, -10.7]), and lower troponin (ES -0.14 ng/mL [95% CI -0.26, -0.03]). Patients admitted in the Omicron versus Alpha eras were younger (ES -1.6 years [95% CI -2.5, -0.8]), had less frequent SIRS (RD -0.18 [95% CI -0.30, -0.05]), lower lymphocyte count (ES -0.39 × 109/uL [95% CI -0.52, -0.25]), lower troponin (ES -0.16 ng/mL [95% CI -0.30, -0.01]) and less frequently received anticoagulation therapy (RD -0.19 [95% CI -0.37, -0.04]). Length of hospitalization was shorter in the Delta versus Alpha eras (-1.3 days [95% CI -2.3, -0.4]).

Interpretation

Our study suggested that MIS-C clinical phenotypes varied across SARS-CoV-2 eras, with patients in Delta and Omicron eras being younger and less sick. EHR data can be effectively leveraged to identify rare complications of pandemic diseases and their variation over time.

Funding

None.

Case report: Presentations and cytokine profiles of inflammatory non-pulmonary COVID-19 and related diseases in children

The coronavirus disease 2019 (COVID-19) pandemic has evolved to dynamic waves of different SARS-CoV-2 variants. Initially, children diagnosed with COVID-19 presented pulmonary involvement characterized by mild diseases. In the later waves of the COVID-19 pandemic, life-threatening non-pulmonary inflammatory diseases such as (1) aseptic meningoencephalitis (ME), (2) acute necrotizing encephalopathies (ANE), and (3) multisystem inflammatory syndrome in children (MIS-C) have been reported, affecting the pediatric population. To alert timely identification and prevention of the life-threatening non-pulmonary COVID-19, we present the cases of ME, ANE, and MIS-C in terms of clinical manifestation, cytokine profile, and follow-up consequences. Based on the immunopathogenesis and risk factors associated with non-pulmonary COVID-19, we delineate strategies for an early diagnosis and treatment to reduce morbidity and mortality in children.