COVID-19 Disease Severity in Children Infected with the Omicron Variant

Multicentre analysis of severe perioperative adverse events in children undergoing surgery who were infected with SARS-CoV-2: a propensity score-adjusted analysis

BACKGROUND

The incidence of severe adverse events in children with SARS-CoV-2 undergoing anaesthesia has not been well established. We examined the relationship between SARS-CoV-2 infection and severe perioperative adverse events in children.

METHODS

This multicentre (21 North American institutions), retrospective cohort study included children <18 years old, with American Society of Anesthesiologists physical status (ASA PS) of 1-4 and non-severe SARS-CoV-2, who underwent general anaesthesia between April 1, 2020, and March 31, 2021. The primary outcome was the incidence of severe perioperative adverse events (admission to the intensive care unit for escalation of respiratory support, acute respiratory distress syndrome, postoperative pneumonia, cardiovascular arrest, extracorporeal life support, and death) within 7 days of the anaesthetic, assessed using multivariable analysis with inverse probability of treatment weighting by the propensity score. A propensity score mixed-effects model included variables selected a priori. Inverse probability of treatment weighting was used to retain all data while balancing exposure groups on measured confounders.

RESULTS

We matched 1138 patients with SARS-CoV-2 positive testing within 10 days of the anaesthetic to 3396 non-infected controls. The cohort included 56.6% (2568/4534) male patients, 69.9% (2839/4060) White patients, and 63.5% (2879/4533) ASA PS 1-2 patients. General surgery cases comprised 38.4% (1739/4534) of the cohort, followed by orthopaedic surgery at 12.6% (573/4534) and ear, nose, and throat surgery at 8.2% (371/4534). In the overall sample of 4534 patients, 52 had a severe adverse event (0.01%). Children with SARS-CoV-2 had a higher risk of at least one severe adverse event (25/1138 [2.20%] vs 27/3396 [0.80%] in those non-infected; adjusted odds ratio 2.34; 95% confidence interval 1.25-4.39). None of the children with SARS-CoV-2 had a cardiac arrest, required extracorporeal life support, or died.

CONCLUSIONS

In the largest cohort to date of paediatric patients undergoing general anaesthesia, SARS-CoV-2 infection was associated with severe perioperative adverse events, but no children in the infected cohort died.

Incidence of severe and non-severe SARS-CoV-2 infections in children and adolescents: a population-based cohort study using six healthcare databases from Italy, Spain, and Norway

We aim to estimate the incidence rates (IRs) of SARS-CoV-2 infections stratified by disease severity and comorbidities in pediatric population and to describe the COVID-19 vaccination coverage in children with and without comorbidities. A population-based cohort study was conducted in 6 electronic healthcare records databases from Italy, Spain, and Norway. The study lasted from 1 January 2020 to the latest databases' available data in each site, i.e., in Italian ARS Tuscany and PEDIANET: December 2021, in Spanish BIFAP: February 2022; SIDIAP: June 2022, and VID: December 2021. Finally, in Norwegian Health Registries: December 2021. Children and adolescents were included and stratified into three age categories (< 5, 5- < 12, and 12- < 18 years old). IRs (95% confidence intervals) per 100 person-years (PY) for non-severe (positive SARS-CoV-2 test or diagnosis without hospitalization) and severe COVID-19 (hospitalization, intensive care unit admission, and death after COVID-19) are reported. The cumulative COVID-19 vaccination rollout was stratified by population with and without comorbidities. The study population comprised 5,654,040 individuals < 18 years of age (51% females) across the six European databases (median age: 6 years), with 1.4 to 8.5% of them having at least one at-risk comorbidity for severe COVID-19. Incidence rates of severe COVID-19 were low (0-1 per 100 PY) but 3 to 4 times higher among children and adolescents with comorbidities during Omicron BA.1-2 wave in December 2021-January 2022. Percentages of vaccination rollout in the general population were between 13% in PEDIANET-IT and 64% in BIFAP-ICU-ES. In ARS-IT and SIDIAP-IT, vaccination rate in children with comorbidities was slightly lower than that in the general population.

CONCLUSION

Severe COVID-19 was rare across databases, but up to 3 to 4 times higher in children with comorbidities during the predominance of Omicron BA.1-2 variant in winter 2021-2022. COVID-19 vaccination coverage was slightly lower in children with comorbidities in ARS (Tuscany) and SIDIAP (Catalonia) data sources. Our findings will inform future public policies aimed to protect the pediatric population, both within these countries and globally.

WHAT IS KNOWN

• Pediatric population is susceptible to SARS-CoV-2 infection. • COVID-19 severity rates in children vary across study settings and context.

WHAT IS NEW

• This study confirms the low severity rates of COVID-19 in the pediatric population based on a large cohort of children and adolescents residing in Spain, Italy, and Norway. • Incidence of severe COVID-19 in children and adolescents with comorbidities was up to 3 to 4 times higher than in the general pediatric population during the SARS-CoV-2 high transmission wave of Omicron BA.1-2 variant in winter 2021-2022 in Italy and Spain.

SARS-CoV-2 seroprevalence screening study of a children's hospital health care workers

Background

Health care workers (HCWs) are front line responders to the COVID-19 pandemic, but limited data is available for pediatric HCWs, as the research response has largely focused on adult patients and medical personnel that treat these patients.

Methods

We conducted a cross-sectional study of SARS-CoV-2 seroprevalence and risk factors in HCWs at a Children's Hospital in CO, USA from September 2020 to April 2021. Pediatric HCWs were defined as clinical care providers and administrative staff. Seroprevalence was determined using the Epitope SARS-CoV-2 anti-Nucleocapsid IgG assay (San Diego, CA) and the Euroimmun SARS-CoV-2 anti-Spike Protein IgG assay. Risk factors and vaccination status were assessed via questionnaire.

Results

Overall, 110 HCWs were enrolled, 79 subjects were positive for anti-S antibodies and negative for anti-N antibodies, indicating COVID-19 vaccination. 31 subjects had neither anti-N or anti-S antibodies, indicating no exposure to SARS-CoV-2 and no vaccination. 3/110 had a nucleocapsid serology consistent with a SARS-CoV-2 prior infection. Seroprevalence was observed at 2.7%. It was noted that asthma requiring medication was associated with positive serostatus.

Conclusions

During the winter 2020/21, SARS-CoV-2, we found a 2.7% seroprevalence of pediatric HCW at a children's hospital in Colorado. We compared this with publicly available seroprevalence data for seroprevalence rates of pediatric HCWs globally. This suggests that this specific children's hospital COVID-19 personal protective equipment (PPE) and infection control guidelines were effective in limiting SARS-CoV-2 in hospital transmission at the children's hospital prior to the presence of the Delta variant.

How international guidelines recommend treating children who have severe COVID-19 or risk disease progression

AIM

This study reviewed the current knowledge and guidelines on managing COVID-19 in children and proposed a practical approach to drug treatment.

METHODS

We analysed international guidelines from four prominent scientific bodies on treating COVID-19 in children. These were the UK National Institute for Health and Care Excellence, the American National Institutes of Health, the Infectious Diseases Society of America and the Australian National Clinical Evidence Taskforce COVID-19.

RESULTS

Most paediatric patients with COVID-19 only require symptomatic treatment. There was limited evidence on treatment recommendations for children with severe COVID-19 or at risk of disease progression. However, several drugs are available for children and we have summarised the guidelines, in order to provide a concise, practical format for clinicians. All the guidelines agree that nirmatrelvir plus ritonavir or remdesivir can be used as prophylaxis for severe COVID-19 in high-risk patients. Remdesivir can also be used for severe COVID-19 cases. Glucocorticosteroids are recommended, particularly in patients requiring oxygen therapy. Tocilizumab or baricitinib should be reserved for patients with progressive disease and/or signs of systemic inflammation.

CONCLUSION

The guidelines provide useful advice and a degree of consensus on specific drug treatment for children with severe COVID-19 or at risk of progression.

Dynamic clade transitions and the influence of vaccination on the spatiotemporal circulation of SARS-CoV-2 variants

Since 2021, the emergence of variants of concern (VOC) has led Brazil to experience record numbers of in COVID-19 cases and deaths. The expanded spread of the SARS-CoV-2 combined with a low vaccination rate has contributed to the emergence of new mutations that may enhance viral fitness, leading to the persistence of the disease. Due to limitations in the real-time genomic monitoring of new variants in some Brazilian states, we aimed to investigate whether genomic surveillance, coupled with epidemiological data and SARS-CoV-2 variants spatiotemporal spread in a smaller region, can reflect the pandemic progression at a national level. Our findings revealed three SARS-CoV-2 variant replacements from 2021 to early 2022, corresponding to the introduction and increase in the frequency of Gamma, Delta, and Omicron variants, as indicated by peaks of the Effective Reproductive Number (Reff). These distinct clade replacements triggered two waves of COVID-19 cases, influenced by the increasing vaccine uptake over time. Our results indicated that the effectiveness of vaccination in preventing new cases during the Delta and Omicron circulations was six and eleven times higher, respectively, than during the period when Gamma was predominant, and it was highly efficient in reducing the number of deaths. Furthermore, we demonstrated that genomic monitoring at a local level can reflect the national trends in the spread and evolution of SARS-CoV-2.

SARS-CoV-2 Variants and Clinical Outcomes of Special Populations: A Scoping Review of the Literature

The ongoing COVID-19 pandemic has significantly impacted special populations, including immunocompromised individuals, people living with HIV (PLWHIV), pediatric patients, and those with chronic liver disease (CLD). This scoping review aims to map the clinical outcomes of these vulnerable groups when infected with various SARS-CoV-2 variants. The review identifies trends and patterns, noting that early variants, such as Alpha and Delta, are associated with more severe outcomes, including higher hospitalization and mortality rates. In contrast, the Omicron variant, despite its increased transmissibility, tends to cause milder clinical manifestations. The review highlights the necessity for ongoing surveillance and tailored healthcare interventions due to the heterogeneity of patient populations and the evolving nature of the virus. Continuous monitoring and adaptive healthcare strategies are essential to mitigate the impact of COVID-19 on these high-risk groups.

Viral respiratory infections and air pollution: A review focused on research in Poland

The COVID-19 pandemic has reinforced an interest in the relationship between air pollution and respiratory viral infections, indicating that their burden can be increased under poor air quality. This paper reviews the pathways through which air pollutants can enhance susceptibility to such infections and aggravate their clinical course and outcome. It also summarizes the research exploring the links between various viral infections and exposure to solid and gaseous pollution in Poland, a region characterized by poor air quality, especially during a heating season. The majority of studies focused on concentrations of particulate matter (PM; 86.7%); the other pollutants, i.e., BaP, benzene, CO, NOx, O3, and SO2, were studied less often and sometimes only in the context of a particular infection type. Most research concerned COVID-19, showing that elevated levels of PM and NO2 correlated with higher morbidity and mortality, while increased PM2.5 and benzo[a]pyrene levels were related to worse clinical course and outcome in hospitalized, regardless of age and dominant SARS-CoV-2 variant. PM10 and PM2.5 levels were also associated with the incidence of influenza-like illness and, along with NO2 concentrations, with a higher rate of children's hospitalizations due to lower respiratory tract RSV infections. Higher levels of air pollutants also increased hospitalization due to bronchitis (PM, NOx, and O3) and emergency department admission due to viral croup (PM10, PM2.5, NOx, CO, and benzene). Although the conducted studies imply only correlations and have other limitations, as discussed in the present paper, it appears that improving air quality through reducing combustion processes in energy production in Poland should be perceived as a part of multilayered protection measures against respiratory viral infections, decreasing the healthcare costs of COVID-19, lower tract RSV infections, influenza, and other respiratory viral diseases prevalent between autumn and early spring, in addition to other health and climate benefits.

Clinical characteristics and outcomes of COVID-19 in children and adolescents with diabetes in Daegu, South Korea

PURPOSE

Children with comorbidities have a higher risk of severe, coronavirus disease 2019 (COVID-19). This study investigated the clinical features and outcomes of COVID-19 in children and adolescents with diabetes between January and March 2022.

METHODS

We retrospectively reviewed the medical records of 123 children and adolescents (73 with type 1 diabetes and 50 with type 2 diabetes, 59 males and 64 females) aged <18 years who had been diagnosed with diabetes. Data were collected from 7 academic medical centers in Daegu, South Korea.

RESULTS

Thirty-five children with diabetes were diagnosed with COVID-19 (18 with type 1 and 17 with type 2 diabetes). Eighteen of the 35 children with diabetes and COVID-19 and 50 of the 88 children with diabetes alone received a COVID-19 vaccination. No significant differences were observed between patients with diabetes and COVID-19 and patients with diabetes alone in the type of diabetes diagnosed, sex, age, body mass index, hemoglobin A1c, or vaccination status. All children with diabetes and COVID-19 had mild clinical features and were safely managed in their homes. Fourteen children had a fever of 38℃ or higher that lasted for more than 2 days, 11 of whom were not vaccinated (p=0.004). None experienced post-COVID-19 conditions.

CONCLUSION

All children and adolescents with pre-existing diabetes had mild symptoms of COVID-19 due to low disease severity, high vaccination rates, uninterrupted access to medical care, and continuous glucose monitoring. Unvaccinated children with diabetes who experienced COVID-19 presented with higher and more frequent fevers compared to vaccinated children.

Real-world utilisation of SARS-CoV-2 rapid antigen testing to enable face-to-face learning in Australian schools, an ecological study

OBJECTIVE

The objective of this study was to describe the use of SARS-CoV-2 rapid antigen testing of COVID-19 contacts in New South Wales schools to determine return to in-person school attendance instead of home quarantine, between 6 November and 21 December 2021.

METHODS

COVID-19 school contacts were required to quarantine for two weeks postexposure to the case. Students who opted into daily rapid antigen testing logged their results in a database, prior to school attendance, and obtained SARS-CoV-2 nucleic amplification acid testing on day 12-16. Secondary attack rates (SARs) in schools utilising rapid antigen testing (Test-to-Stay schools) and those not utilising rapid antigen testing (non-Test-to-Stay school) were calculated.

RESULTS

We identified 9,887 people in 293 schools who reported performing at least one rapid antigen test (RAT). The SAR in RAT schools was 3.4% (95% confidence interval: 2.7-4.1) and non-RAT schools was 2.8% (95% confidence interval: 2.4-3.3). A total of 30,535 school days were preserved through this program.

CONCLUSIONS

The use of RATs preserved in-person learning without a significant increase to SAR.

IMPLICATION FOR PUBLIC HEALTH

Disruptions in face-to-face learning have long-term detrimental impacts on children and adolescents. Rapid antigen testing has been shown to be beneficial to maintain face-to-face learning in Australian schools and may be a useful method to safeguard from school disruptions in future pandemics.

Transmission risks of Omicron BA.5 following inactivated COVID-19 vaccines among children and adolescents in China

BACKGROUND

As SARS-CoV-2 Omicron variants circulating globally since 2022, assessing the transmission characteristics, and the protection of vaccines against emerging Omicron variants among children and adolescents are needed for guiding the control and vaccination policies.

METHODS

We conducted a retrospective cohort study for SARS-CoV-2 infections and close contacts aged <18 years from an outbreak seeded by Omicron BA.5 variants. The secondary attack rate (SAR) was calculated and the protective effects of two doses of inactivated vaccine (mainly Sinopharm /BBIBP-CorV) within a year versus one dose or two doses above a year after vaccination against the transmission and infection of Omicron BA.5 were estimated.

RESULTS

A total of 3442 all-age close contacts of 122 confirmed SARS-CoV-2 infections aged 0-17 years were included. The SAR was higher in the household setting and for individuals who received a one-dose inactivated vaccine or those who received a two-dose for more than one year, with estimates of 28.5% (95% credible interval [CrI]: 21.1, 37.7) and 55.3% (95% CrI: 24.4, 84.8), respectively. The second dose of inactivated vaccine conferred substantial protection against all infection and transmission of Omicron BA.5 variants within a year.

CONCLUSIONS

Our findings support the rollout of the second dose of inactivated vaccine for children and adolescents during the Omciron BA.5 predominant epidemic phase. Given the continuous emergence of SARS-CoV-2 variants, monitoring the transmission risk and corresponding vaccine effectiveness against SARS-CoV-2 variants among children and adolescents is important to inform control strategy.

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

Objective

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

Methods

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

Results

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

Conclusions

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

A robust web-based tool to predict viral shedding in patients with Omicron SARS-CoV-2 variants

Background

Data on viral kinetics and variants affecting the duration of viral shedding were limited. Our objective was to determine viral shedding in distinct severe acute respiratory syndrome coronavirus 2 variants, including Omicron BA.4/5 and BF.7, and to identify the relevant influencing factors.

Methods

We carried out a longitudinal cohort study at Beijing Xiaotangshan Fangcang shelter hospital from May to June 2022 (Omicron BA.4/5) and from November to December 2022 (Omicron BF.7). Nucleocapsid protein (N) and open reading frame (ORF) genes were considered as the target genes of the reverse transcription PCR. The daily results of cycle threshold (CT), including lowest ORF1ab-CT values for days 1-3 post-hospitalisation and lowest N-CT values for days 1-3 post-hospitalisation (CT3minN) and demographic and clinical characteristics were collected.

Results

1433 patients with coronavirus disease 2019 (COVID-19) were recruited from the Fangcang shelter hospital, in which 278 patients were diagnosed with Omicron BA.4/5 and 1155 patients with Omicron BF.7. Patients with BF.7 infection showed a longer duration of viral shedding. The duration of viral shedding was associated with the variants age, alcohol use, the severity of COVID-19 and CT3minN. Moreover, the nomogram had excellent accuracy in predicting viral shedding.

Conclusions

Our results indicated that patients with Omicron BF.7 had a longer period of contagiousness than those with BA.4/5. The duration of viral shedding was affected by a variety of factors and the nomogram may become an applicable clinical instrument to predict viral shedding. Furthermore, we developed a new COVID-19 viral shedding predicting model that can accurately predict the duration of viral shedding for COVID-19, and created a user-friendly website to apply this prediction model (https://puh3.shinyapps.io/CVSP_Model/).

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

AIM

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

METHODS

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

RESULTS

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

CONCLUSION

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

Clinical Outcomes of Children With COVID-19 by SARS-CoV-2 Strain: A Cohort Study

OBJECTIVE

We sought to investigate the disease outcomes and predictors of severe outcomes among children infected with the Delta variant of SARS-CoV-2 compared with pre-Delta strains.

METHODS

Single-center retrospective cohort study in an emergency department located within an urban academic children's hospital. Patients included children (0-18 years) who tested positive for SARS-CoV-2. Main outcomes measured include need for hospital admission or COVID-directed therapies.

RESULTS

There was a trend toward decreased hospital admission and no significant difference in the severity of outcomes in the Delta cohort relative to the pre-Delta cohort. The Delta cohort had lower odds of hospital admission (odds ratio [OR], 0.79; 95% confidence interval [CI], 0.51-1.23), but the result was not statistically significant. Logistic regression analyses showed that overall, age 1 to 4 years (OR, 2.35; 95% CI, 1.23-4.57) and public insurance (OR, 1.80, 95% CI, 1.08-3.01) were predictors of hospital admission. Within the Delta cohort, the presence of any comorbidity increased the odds of admission (OR, 2.52; 95% CI, 1.09-6.04). Black children had lower odds of admission than white children (overall OR, 0.53; 95% CI, 0.31-0.90; pre-Delta OR, 0.50; 95% CI, 0.26-0.95).

CONCLUSIONS

The severity of measured disease outcomes was similar in pediatric patients when comparing children infected with the pre-Delta and Delta variants of SARS-CoV-2, even among children with comorbidities once adjusting for acuity.Ongoing research is essential to determine disease severity and risk for children with comorbidities because SARS-CoV-2 continues to mutate, including with Omicron subvariants.

Risk Factors for Severe and Critical Coronavirus Disease 2019 in Children

BACKGROUND

Coronavirus disease 2019 (COVID-19) is generally mild in children; however, severe or critical cases may occur. In this nationwide study, we analyzed clinical manifestations in children diagnosed with severe acute respiratory syndrome coronavirus 2 to identify high-risk groups for severe or critical disease and compared the clinical features between the Delta- and Omicron-dominant periods.

METHODS

Data were retrieved from the National Health Insurance Service (NHIS) database and merged with the Korea Disease Control and Prevention Agency-COVID-19-NHIS cohort, which includes information on COVID-19 cases and vaccination records. We included individuals <20 years old diagnosed with COVID-19 during both periods (Delta: July 25, 2021-January 15, 2022; Omicron: January 16, 2022-March 31, 2022).

RESULTS

Proportion of severe or critical cases was higher during the Delta period than during the Omicron period. The Omicron period saw increased hospitalization for pneumonia and croup and increased likelihood of hospitalization for neurological manifestations. The risk of severe COVID-19 depended on age group (Delta: highest for 12-19 years; Omicron: 0-4 years). This risk was high in children with multiple complex chronic conditions during both periods and with obesity or asthma during the Delta but not during the Omicron period. Two-dose COVID-19 vaccination provided strong protection against severe disease in the Delta period (adjusted odds ratio: 0.20), with reduced effectiveness in the Omicron period (adjusted odds ratio: 0.91). However, it significantly reduced the risk of critical illness (adjusted odds ratio: 0.14).

CONCLUSIONS

These findings can facilitate identification of children at high risk of severe or critical COVID-19, who may require intensive medical support, and development of vaccination policies.

Clinical characteristics of SARS-CoV-2-associated encephalopathy in children: Nationwide epidemiological study

OBJECTIVE

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sometimes triggers acute encephalopathy as a serious neurological complication in children. We previously reported the clinico-radiological findings of SARS-CoV-2-associated encephalopathy. The advent of the SARS-CoV-2 omicron variant led to a marked increase in pediatric patients with coronavirus disease 2019 (COVID-19); however, epidemiological changes with acute encephalopathy according to the emergence of SARS-CoV-2 have not yet been documented. Therefore, the present study investigated epidemiological differences in SARS-CoV-2-associated encephalopathy during the BA.1/BA.2 and BA.5 predominant periods and also between SARS-CoV-2-associated and non-SARS-CoV-2-associated encephalopathy.

METHODS

We conducted a nationwide survey of SARS-CoV-2-associated encephalopathy in Japanese children between June and November 2022. We compared the present results during the BA.5 predominant period and previous findings during the BA.1/BA.2 predominant period. We also compared the clinico-radiological syndromes of encephalopathy between SARS-CoV-2-associated and non-SARS-CoV-2-associated encephalopathy.

RESULTS

Although many patients with SARS-CoV-2-associated encephalopathy in the BA.5 predominant period had seizures as their initial symptoms, no significant differences were observed in the clinical features. Patients with SARS-CoV-2-associated encephalopathy had worse outcomes than those with non-SARS-CoV-2-associated encephalopathy (p-value = 0.003). Among 103 patients with SARS-CoV-2-associated encephalopathy, 14 (13.6%) had severe types of acute encephalopathy, namely, encephalopathy with acute fulminant cerebral edema (AFCE) and hemorrhagic shock and encephalopathy syndrome (HSES). Also, 28 (27.2%) patients with SARS-CoV-2-associated encephalopathy had poor outcome: severe neurological sequelae or death. Ninety-five patients (92.2%) were not vaccinated against SARS-CoV-2.

CONCLUSIONS

In SARS-CoV-2-associated encephalopathy, high percentages of AFCE and HSES can result in poor outcomes.

Effectiveness of Bivalent mRNA COVID-19 Vaccines in Preventing SARS-CoV-2 Infection in Children and Adolescents Aged 5 to 17 Years

Importance

Bivalent mRNA COVID-19 vaccines were recommended in the US for children and adolescents aged 12 years or older on September 1, 2022, and for children aged 5 to 11 years on October 12, 2022; however, data demonstrating the effectiveness of bivalent COVID-19 vaccines are limited.

Objective

To assess the effectiveness of bivalent COVID-19 vaccines against SARS-CoV-2 infection and symptomatic COVID-19 among children and adolescents.

Design, Setting, and Participants

Data for the period September 4, 2022, to January 31, 2023, were combined from 3 prospective US cohort studies (6 sites total) and used to estimate COVID-19 vaccine effectiveness among children and adolescents aged 5 to 17 years. A total of 2959 participants completed periodic surveys (demographics, household characteristics, chronic medical conditions, and COVID-19 symptoms) and submitted weekly self-collected nasal swabs (irrespective of symptoms); participants submitted additional nasal swabs at the onset of any symptoms.

Exposure

Vaccination status was captured from the periodic surveys and supplemented with data from state immunization information systems and electronic medical records.

Main Outcome and Measures

Respiratory swabs were tested for the presence of the SARS-CoV-2 virus using reverse transcriptase-polymerase chain reaction. SARS-CoV-2 infection was defined as a positive test regardless of symptoms. Symptomatic COVID-19 was defined as a positive test and 2 or more COVID-19 symptoms within 7 days of specimen collection. Cox proportional hazards models were used to estimate hazard ratios for SARS-CoV-2 infection and symptomatic COVID-19 among participants who received a bivalent COVID-19 vaccine dose vs participants who received no vaccine or monovalent vaccine doses only. Models were adjusted for age, sex, race, ethnicity, underlying health conditions, prior SARS-CoV-2 infection status, geographic site, proportion of circulating variants by site, and local virus prevalence.

Results

Of the 2959 participants (47.8% were female; median age, 10.6 years [IQR, 8.0-13.2 years]; 64.6% were non-Hispanic White) included in this analysis, 25.4% received a bivalent COVID-19 vaccine dose. During the study period, 426 participants (14.4%) had laboratory-confirmed SARS-CoV-2 infection. Among these 426 participants, 184 (43.2%) had symptomatic COVID-19, 383 (89.9%) were not vaccinated or had received only monovalent COVID-19 vaccine doses (1.38 SARS-CoV-2 infections per 1000 person-days), and 43 (10.1%) had received a bivalent COVID-19 vaccine dose (0.84 SARS-CoV-2 infections per 1000 person-days). Bivalent vaccine effectiveness against SARS-CoV-2 infection was 54.0% (95% CI, 36.6%-69.1%) and vaccine effectiveness against symptomatic COVID-19 was 49.4% (95% CI, 22.2%-70.7%). The median observation time after vaccination was 276 days (IQR, 142-350 days) for participants who received only monovalent COVID-19 vaccine doses vs 50 days (IQR, 27-74 days) for those who received a bivalent COVID-19 vaccine dose.

Conclusion and Relevance

The bivalent COVID-19 vaccines protected children and adolescents against SARS-CoV-2 infection and symptomatic COVID-19. These data demonstrate the benefit of COVID-19 vaccine in children and adolescents. All eligible children and adolescents should remain up to date with recommended COVID-19 vaccinations.

Acute and persistent symptoms of COVID-19 infection in school-aged children: a retrospective study from China

BACKGROUND

The long-term sequelae of Coronavirus disease 2019 (COVID-19) in children are unclear. We investigated COVID-19 symptoms in school-aged children to determine their impact on patients and their families.

METHODS

This cross-sectional study, conducted on February 25-28, 2023, selected a representative kindergarten and 9-year school from Shenzhen, China. There were randomly two classes each for the 12 grades from kindergarten to junior high school. The school-aged children were aged 3-16 years. Literate parents completed an online questionnaire related to their children's COVID-19 symptoms since December 1, 2022. Descriptive statistics were computed as necessary. Univariate and multivariable linear regression analyses were performed, and variables with a p-value < 0.05 were considered to have a significant association with the subjective feeling scores for COVID-19 infection.

RESULTS

We included 936 school-aged children, with a COVID-19 infection rate of 68.5%. The prevalence of LC 28 (illness with symptoms lasting for 28 days) was 3.4%. During acute infection, the median number of the 641 children's symptoms was 3.0 (IQR: 1.0-5.0) and the median score of subjective feelings was 15.0 (IQR: 11.0-24.5). The top three symptoms were fever, cough/expectoration, and rhinobyon. Age of 13-16 years (adjusted beta: 3.60, 95% CI: 0.32-6.88) and comorbidities (adjusted beta: 3.47, 95% CI: 1.20-5.73) were independently associated with higher subjective feelings (p < 0.05). The top three characteristics associated with LC 28 were alopecia (33.3%, 5/15), cognitive dysfunction (29.2%, 7/24), and emotional problem (28.6%, 6/21).

CONCLUSIONS

Children with COVID-19 have a short duration of symptoms and milder symptoms, so they can self-medicate to minimize hospital crowding. Children with basic diseases require prompt attention. Although LC 28 is uncommon in children, mental and psychological problems after COVID-19 recovery should not be ignored.

Dynamic clade transitions and the influence of vaccine rollout on the spatiotemporal circulation of SARS-CoV-2 variants in São Paulo, Brazil

Since 2021, the emergence of variants of concern (VOC) has led Brazil to experience record numbers of in COVID-19 cases and deaths. The expanded spread of the SARS-CoV-2 combined with a low vaccination rate has contributed to the emergence of new mutations that may enhance viral fitness, leading to the persistence of the disease. Due to limitations in the real-time genomic monitoring of new variants in some Brazilian states, we aimed to investigate whether genomic surveillance, coupled with epidemiological data and SARS-CoV-2 variants spatiotemporal spread in a smaller region, can reflect the pandemic progression at a national level. Our findings revealed three SARS-CoV-2 variant replacements from 2021 to early 2022, corresponding to the introduction and increase in the frequency of Gamma, Delta, and Omicron variants, as indicated by peaks of the Effective Reproductive Number (Reff). These distinct clade replacements triggered two waves of COVID-19 cases, influenced by the increasing vaccine uptake over time. Our results indicated that the effectiveness of vaccination in preventing new cases during the Delta and Omicron circulations was six and eleven times higher, respectively, than during the period when Gamma was predominant, and it was highly efficient in reducing the number of deaths. Furthermore, we demonstrated that genomic monitoring at a local level can reflect the national trends in the spread and evolution of SARS-CoV-2.

Integration of individualized and population-level molecular epidemiology data to model COVID-19 outcomes

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants with enhanced transmissibility and immune escape have emerged periodically throughout the coronavirus disease 2019 (COVID-19) pandemic, but the impact of these variants on disease severity has remained unclear. In this single-center, retrospective cohort study, we examined the association between SARS-CoV-2 clade and patient outcome over a two-year period in Chicago, Illinois. Between March 2020 and March 2022, 14,252 residual diagnostic specimens were collected from SARS-CoV-2-positive inpatients and outpatients alongside linked clinical and demographic metadata, of which 2,114 were processed for viral whole-genome sequencing. When controlling for patient demographics and vaccination status, several viral clades were associated with risk for hospitalization, but this association was negated by the inclusion of population-level confounders, including case count, sampling bias, and shifting standards of care. These data highlight the importance of integrating non-virological factors into disease severity and outcome models for the accurate assessment of patient risk.

Epidemiology of 7375 children and adolescents hospitalized with COVID-19 in Germany, reported via a prospective, nationwide surveillance study in 2020-2022

By means of a nationwide, prospective, multicenter, observational cohort registry collecting data on 7375 patients with laboratory-confirmed SARS-CoV-2 admitted to children's hospitals in Germany, March 2020-November 2022, our study assessed the clinical features of children and adolescents hospitalized due to SARS-CoV-2, evaluated which of these patients might be at highest risk for severe COVID-19, and identified underlying risk factors. Outcomes tracked included: symptomatic infection, case fatality, sequelae at discharge and severe disease. Among reported cases, median age was one year, with 42% being infants. Half were admitted for reasons other than SARS-CoV-2. In 27%, preexisting comorbidities were present, most frequently obesity, neurological/neuromuscular disorders, premature birth, and respiratory, cardiovascular or gastrointestinal diseases. 3.0% of cases were admitted to ICU, but ICU admission rates varied as different SARS-CoV-2 variants gained prevalence. Main risk factors linked to ICU admission due to COVID-19 were: patient age (> 12 and 1-4 years old), obesity, neurological/neuromuscular diseases, Trisomy 21 or other genetic syndromes, and coinfections at time of hospitalization. With Omicron, the group at highest risk shifted to 1-4-year-olds. For both health care providers and the general public, understanding risk factors for severe disease is critical to informing decisions about risk-reduction measures, including vaccination and masking guidelines.

Clinical severity of Omicron and Delta SARS-CoV-2 infections in children

BACKGROUND

We aimed to compare the clinical features and severity of the Omicron and Delta variant infections among children hospitalized for coronavirus disease 2019 (COVID-19).

METHODS

Children 12 years old or less hospitalized for COVID-19 across five hospitals between January 1, 2021 and March 31, 2022 were identified using the state's pediatric COVID-19 registry. Delta and Omicron-infected patients without previous COVID-19 infection, COVID-19 vaccination, or co-infections were propensity-score matched 1:1 to control for differences in baseline characteristics. Clinical manifestations, treatments, and outcomes were analyzed. Disease severity was assessed using an adapted WHO ordinal scale.

RESULTS

Of the initial 1367 patients, 668 had Delta infection and 699 had Omicron infection. Propensity-score matching produced 558 matched pairs. Patients with Omicron infection were more likely to present with croup (the odds ratio, OR, was 10.87, with a 95% confidence interval, CI, ranging from 2.54 to 46.59), lower respiratory tract infection (OR 2.32, 95% CI, 1.48-3.64) and seizures (OR 8.39, 95% CI, 5.04-13.99) compared with those with Delta infection. Omicron was associated with increased odds of moderate/severe disease (OR 6.14, 95% CI, 4.72-7.99) and a greater need for intravenous fluid therapy (OR 6.00, 95% CI, 4.29-8.39), corticosteroids (OR 3.08, 95% CI, 1.66-5.72), empirical antibiotics (OR 1.70, 95% CI, 1.10-2.64), and low-flow nasal oxygen therapy (OR 3.68, 95% CI, 2.17-6.22) in comparison with Delta.

CONCLUSION

Children hospitalized with Omicron infection demonstrated a distinct clinical profile compared to those with Delta infection, with increased likelihood of moderate/severe disease and higher utilization of health-care resources.

SARS-CoV-2 nucleocapsid antigen in plasma of children hospitalized for COVID-19 or with incidental detection of SARS-CoV-2 infection

In hospitalized children, SARS-CoV-2 infection can present as either a primary reason for admission (patients admitted for COVID-19) or an incidental finding during follow-up (patients admitted with COVID-19). We conducted a nested case-control study within a cohort of pediatric patients with confirmed SARS-CoV-2 infection, to investigate the concentration of plasma nucleocapsid antigen (N-Ag) in children admitted for COVID-19 or with COVID-19. While reverse transcriptase polymerase chain reaction Ct values in nasopharyngeal swab were similar between the two groups, children admitted for COVID-19 had a higher rate of detectable N-Ag (12/18 (60.7%) versus 6/18 (33.3%), p = 0.0455) and a higher concentration of N-Ag (medians: 19.51 g/mL vs. 1.08 pg/mL, p = 0.0105). In children hospitalized for COVID-19, the youngest had higher concentration of N-Ag (r = -0.74, p = 0.0004). We also observed a lower prevalence of detectable spike antibodies in children hospitalized for COVID-19 compared to those hospitalized for other medical reasons (3/15 [20%] vs. 13/16 [81.25%], respectively, p = < 0.0011), but similar rates of IgG nucleocapsid antibodies (5/14 [35.7%] vs. 6/17 [35.3%], respectively, p = 0.99). Our findings indicate that N-Ag is associated with COVID-19-related hospitalizations in pediatric patients, and less frequently detected in children tested positive for SARS-CoV-2 but hospitalized for another medical reason. Further studies are needed to confirm the value of N-Ag in identifying COVID-19 disease infections in which SARS-CoV-2 is the main pathogen responsible for symptoms.

Gastrointestinal Manifestations Are Associated with Severe COVID-19 in Children

Purpose: Although less severe than in adults, children can experience a range of COVID-19 symptoms, from asymptomatic to life-threatening, including respiratory and gastrointestinal symptoms. Medical conditions may also increase the severity of the disease in infected children. Methods: This study was performed at a single center, comparing cases and controls, and involving 253 pediatric patients who had been diagnosed with COVID-19. Two different outcomes were assessed. The first categorized symptomatic individuals who were hospitalized with COVID-19 (hospital) from those who were not (nonhospital). The second categorized admitted individuals who spent at least one day in the intensive care unit (ICU) from those who did not require intensive care (floor). Results: Ninety individuals (36%) had at least one underlying medical condition, the most common being pulmonary disorders, such as asthma (12%), followed by neurodevelopmental disorders (8%), gastrointestinal disorders (6%), and seizure disorders (6%). The hospital group was more likely to have a comorbidity, such as obstructive sleep apnea (OSA), diabetes mellitus, seizure disorder, hypertension, sickle cell disease, neurodevelopmental disorder, and immunocompromising conditions, including cancer, bone marrow transplant, and other immunodeficiencies, compared to the non-hospital group. Abdominal pain was more common in the hospital group. Shortness of breath (SOB) and diarrhea were significantly more common in the ICU group than in the floor group. Conclusions: Early identification of pediatric patients with severe COVID-19 is important to improve outcomes. In our single-center case-control study, we found that the presence of gastrointestinal symptoms on presentation was more commonly associated with severe COVID-19 in children.

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

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

Sociodemographic factors and attitudes associated with Australian parental acceptance of paediatric COVID-19 vaccination

INTRODUCTION

The COVID-19 vaccine coverage among children in countries where COVID-19 vaccines are recommended has been suboptimal. Conflicting information in the media leads to parental anxiety and confusion around COVID-19 vaccination in children. The scepticism expressed by certain experts regarding the importance of COVID-19 vaccines in children has also had a negative impact on parental attitudes towards COVID-19 vaccination. This study aimed to understand parental concerns and preferences for paediatric COVID-19 vaccination, and identify potential vaccination promotion ("nudge") interventions to optimise paediatric COVID-19 vaccine uptake.

METHODS

Mixed methods including Focus Group Discussions and a Discrete Choice Experiment survey were used. The Discrete Choice Experiment survey design was based on a literature review and the findings of Focus Group Discussions. The study was conducted on a nationally representative sample of parents in Australia.

RESULTS

In total, 1039 parents participated in the study. Parents showed strong preferences for a COVID-19 vaccine with lower risk of serious side effects and longer protection duration, followed by higher vaccine effectiveness and delivery via oral tablets. Promotion strategies were similarly preferred by parents. Latent class logit analysis identified three groups, interpretable as COVID-19 vaccine "accepters (35.3%)", "deliberators (31.7%)", and "rejecters (33.1%)". The "deliberators" composed of more parents, residing in metropolitan areas, having concerns about vaccine effectiveness, and believing that disease risks outweigh vaccine benefits than the "accepters". The "rejecters" were more likely to not be vaccinated themselves, and generally have less trust in vaccines than the "accepters". The "deliberators" and "rejecters" were less likely to be parents aged ≥25 years and complete final year of high school than the "accepters".

CONCLUSIONS

Parents' sociodemographic factors and vaccine perceptions were associated with different levels of acceptance toward paediatric COVID-19 vaccination, which may help to better understand how to "nudge" vaccine hesitancy.

SARS-CoV-2 reinfections in the pediatric cohort-a single-center experience

BACKGROUND

This study focused on timelines of infection episodes and dominant variants and aims to determine disease severity and outcome of pediatric patients with reinfection.

MATERIALS AND METHODS

This study retrospectively evaluated the medical records of the hospitalized patients and/or outpatients aged 0-18 with a positive severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) polymerase chain reaction between March 2020 and September 2022 at Ege University Children's Hospital.

RESULTS

Ninety-one pediatric patients reinfected with SARS-CoV-2 were included in the study. There was an underlying disease in 26.4% of the patients. The median time between the two infection episodes was 184 (90-662) days. There were 24 patients (26.3%) with the first infection in pre-Delta period; 17 (18.6%) of them were reinfected in Omicron BA.1 period, while 7 (7.6%) in Omicron BA.4/BA.5 period. Forty-five patients (49.4%) were infected initially in the Delta period; 35 patients (38.4%) were reinfected in the Omicron BA.1 period, while 10 patients (10.9%) were reinfected in the Omicron BA.4/BA.5 period. Twenty-two patients (24.1%) had the first infection in the Omicron BA.1 period and then reinfected in the Omicron BA.4/BA.5 period. Patients with reinfection more frequently displayed a symptom (84.6% vs. 94.5%, p = 0.03). The hospitalization rate significantly declined in reinfection (15.3% vs. 7.6%, p = 0.03). Severe disease, treatment needs and steroid use were decreased in reinfections without a significant difference (p > 0.05). Intensive care unit admission was not altered.

CONCLUSION

This study revealed that reinfections frequently develop in previously healthy children but do not cause more severe outcomes. The risk of symptomatic reinfections is still high due to the effect of the Omicron variant.

Does equipoise exist for masking children for COVID-19?

Clinical equipoise is characterized by genuine uncertainty within the medical community about the effectiveness of a medical intervention. Its existence is often deemed necessary for clinical trials and signals a need for higher quality evidence, most often with randomized controlled trials, before the intervention can be considered effective. A leading official of the United States' Centers for Disease Control and Prevention Director, when testifying before Congress in February of 2023, indicated there was no need for randomized controlled trials of masking because, owing to overwhelming evidence of benefit, there was no longer equipoise about masking children for COVID-19. We disagree with this statement and outline the reasons why in this piece. We review the concept of clinical equipoise specifically using the example of child masking. We list reasons equipoise still exists for masking children, including a lack of consensus among experts, contradictory medical evidence and recent and ongoing randomized efforts. Finally, we differentiate between clinical equipoise and ethical appropriateness. Despite ongoing equipoise about masking children, we outline why, owing to lack of evidence of net benefit, recommending this intervention does not currently appear to be medically ethical.

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.

Short- and longer-term all-cause mortality among SARS-CoV-2- infected individuals and the pull-forward phenomenon in Qatar: a national cohort study

OBJECTIVES

We assessed short-, medium-, and long-term all-cause mortality risks after a primary SARS-CoV-2 infection.

METHODS

A national, matched, retrospective cohort study was conducted in Qatar to assess risk of all-cause mortality in the national SARS-CoV-2 primary infection cohort compared with the national infection-naïve cohort. Associations were estimated using Cox proportional-hazards regression models. Analyses were stratified by vaccination status and clinical vulnerability status.

RESULTS

Among unvaccinated persons, within 90 days after primary infection, the adjusted hazard ratio (aHR) comparing mortality incidence in the primary-infection cohort with the infection-naïve cohort was 1.19 (95% confidence interval 1.02-1.39). aHR was 1.34 (1.11-1.63) in persons more clinically vulnerable to severe COVID-19 and 0.94 (0.72-1.24) in those less clinically vulnerable. Beyond 90 days after primary infection, aHR was 0.50 (0.37-0.68); aHR was 0.41 (0.28-0.58) at 3-7 months and 0.76 (0.46-1.26) at ≥8 months. The aHR was 0.37 (0.25-0.54) in more clinically vulnerable persons and 0.77 (0.48-1.24) in less clinically vulnerable persons. Among vaccinated persons, mortality incidence was comparable in the primary-infection versus infection-naïve cohorts, regardless of clinical vulnerability status.

CONCLUSIONS

COVID-19 mortality was primarily driven by an accelerated onset of death among individuals who were already vulnerable to all-cause mortality, but vaccination prevented these accelerated deaths.

Clinical manifestations and outcomes of coronavirus disease 2019 among pediatric liver transplant recipients in the delta and omicron variant pandemic: A retrospective study

To determine the clinical manifestations and outcomes of the coronavirus disease 2019 (COVID-19) in children who underwent liver transplantation (LT). A retrospective study was conducted at a transplant center in Thailand to include LT recipients aged < 18 years who had been infected with COVID-19. Out of a total of 54 children, there were 31 probable cases (57.4%) diagnosed using an antigen test kit and 23 confirmed cases (42.6%) diagnosed using polymerase chain reaction (14 children) or severe acute respiratory syndrome coronavirus 2 antigen (9 children). Approximately half of the children (25, 46.3%) received the BNT162b2 vaccine before the infection, with 3 and 2 doses in 5 and 18 children, respectively. While some had COVID-19 during the delta pandemic, most (46 children, 85.2%) were infected during the omicron pandemic, of which manifestations included fever (67.4%), cough (50%), and rhinorrhea (47.8%), and symptoms lasted approximately 3 days. None had severe diseases. All patients with mild-to-moderate disease were advised to continue the same immunosuppressive therapy as before the infection. Compared to unvaccinated children or children with one dose of the vaccine, fever was less common in those who received ≥ 2 doses (OR: 0.08; 95%CI: 0.01-0.57, adjusted for age and immunosuppressive types). Favipiravir was prescribed in most patients (90.7%). Only a few children had long COVID-19 or abnormal liver function tests lasting > 1 month (4 children, 7.4%, both). Pediatric LT recipients with COVID-19 during the delta and omicron variant pandemic reported mild symptoms despite undergoing immunosuppressive therapy.

SARS-CoV-2 variants of concern in children and adolescents with COVID-19: a systematic review

OBJECTIVES

Infections by SARS-CoV-2 variants of concern (VOCs) might affect children and adolescents differently than earlier viral lineages. We aimed to address five questions about SARS-CoV-2 VOC infections in children and adolescents: (1) symptoms and severity, (2) risk factors for severe disease, (3) the risk of infection, (4) the risk of transmission and (5) long-term consequences following a VOC infection.

DESIGN

Systematic review.

DATA SOURCES

The COVID-19 Open Access Project database was searched up to 1 March 2022 and PubMed was searched up to 9 May 2022.

ELIGIBILITY CRITERIA

We included observational studies about Alpha, Beta, Gamma, Delta and Omicron VOCs among ≤18-year-olds. We included studies in English, German, French, Greek, Italian, Spanish and Turkish.

DATA EXTRACTION AND SYNTHESIS

Two reviewers extracted and verified the data and assessed the risk of bias. We descriptively synthesised the data and assessed the risks of bias at the outcome level.

RESULTS

We included 53 articles. Most children with any VOC infection presented with mild disease, with more severe disease being described with the Delta or the Gamma VOC. Diabetes and obesity were reported as risk factors for severe disease during the whole pandemic period. The risk of becoming infected with a SARS-CoV-2 VOC seemed to increase with age, while in daycare settings the risk of onward transmission of VOCs was higher for younger than older children or partially vaccinated adults. Long-term symptoms following an infection with a VOC were described in <5% of children and adolescents.

CONCLUSION

Overall patterns of SARS-CoV-2 VOC infections in children and adolescents are similar to those of earlier lineages. Comparisons between different pandemic periods, countries and age groups should be improved with complete reporting of relevant contextual factors, including VOCs, vaccination status of study participants and the risk of exposure of the population to SARS-CoV-2.

PROSPERO REGISTRATION NUMBER

CRD42022295207.

Clinical characteristics and factors associated with severe COVID-19 in hospitalized children during the SARS-CoV-2 Omicron pandemic in Taiwan

BACKGROUND

Since April 2022, a notable increase in COVID-19 cases with the rapid spread of the SARS-CoV-2 Omicron variant has been reported in Taiwan. In the epidemic, children were one of the most vulnerable groups, so we analyzed their clinical presentations and factors associated with severe complications of COVID-19 in children.

METHODS

We included hospitalized patients under 18 years old with lab-confirmed SARS-CoV-2 infection from March 1, 2022, to July 31, 2022. We collected the demographic and clinical characteristics of the patients. Patients requiring intensive care were defined as severe cases.

RESULTS

Among the 339 enrolled patients, the median age was 31 months (interquartile range (IQR), 8-79.0 months); and 96 patients (28.3%) had underlying diseases. Fever was noted in 319 patients (94.1%) with a median duration of two days (IQR 2-3 days). Twenty-two patients (6.5%) were severe cases, including 10 patients (2.9%) with encephalopathy with abnormal neuroimaging and ten patients (2.9%) with shock. Two patients (0.6%) died. Patients with congenital cardiovascular disease (aOR: 21.689), duration of fever up to four days or more (aOR: 6.466), desaturation (aOR: 16.081), seizure (aOR: 20.92), and procalcitonin >0.5 ng/mL (aOR: 7.886) had a higher risk of severe COVID-19.

CONCLUSIONS

Vital signs need close monitoring, early management and/or intensive care may be applied in COVID-19 patients with congenital cardiovascular diseases, fever lasting ≥4 days, seizures, desaturation and/or elevated procalcition since they are at higher risks of severe diseases.

Comparing SARS-CoV-2 variants among children and adolescents in Germany: relative risk of COVID-19-related hospitalization, ICU admission and mortality

PURPOSE

SARS-CoV-2 infections cause COVID-19 and have a wide spectrum of morbidity. Severe disease courses among children are rare. To date, data on the variability of morbidity in relation to variant of concern (VOC) in children has been sparse and inconclusive. We compare the clinical severity of SARS-CoV-2 infection among children and adolescents in Germany during the Wildtype and Alpha combined, Delta and Omicron phases of the COVID-19 pandemic.

METHODS

Comparing risk of COVID-19-related hospitalization, intensive care unit (ICU) admission and death due to COVID-19 in children and adolescents, we used: (1) a multi-center seroprevalence study (SARS-CoV-2-KIDS study); (2) a nationwide registry of pediatric patients hospitalized with SARS-CoV-2 infections; and (3) compulsory national reporting for RT-PCR-confirmed SARS-CoV-2 infections in Germany.

RESULTS

During the Delta predominant phase, risk of COVID-19-related hospitalization among all SARS-CoV-2 seropositive children was 3.35, ICU admission 1.19 and fatality 0.09 per 10,000; hence about halved for hospitalization and ICU admission and unchanged for deaths as compared to the Wildtype- and Alpha-dominant period. The relative risk for COVID-19-related hospitalization and ICU admission compared to the alpha period decreased during Delta [0.60 (95% CI 0.54; 0.67) and 0.51 (95% CI 0.42; 0.61)] and Omicron [0.27 (95% CI 0.24; 0.30) and 0.06 (95% CI 0.05; 0.08)] period except for the < 5-year-olds. The rate of case fatalities decreased slightly during Delta, and substantially during Omicron phase.

CONCLUSION

Morbidity caused by SARS-CoV-2 infections among children and adolescents in Germany decreased over the course of the COVID-19 pandemic, as different VOCs) emerged.

SARS-CoV-2 sero-immunity and quality of life in children and adolescents in relation to infections and vaccinations: the IMMUNEBRIDGE KIDS cross-sectional study, 2022

PURPOSE

The study evaluates the effects on sero-immunity, health status and quality of life of children and adolescents after the upsurge of the Omicron variant in Germany.

METHODS

This multicenter cross-sectional study (IMMUNEBRIDGE Kids) was conducted within the German Network University Medicine (NUM) from July to October 2022. SARS-CoV-2- antibodies were measured and data on SARS-CoV-2 infections, vaccinations, health and socioeconomic factors as well as caregiver-reported evaluation on their children's health and psychological status were assessed.

RESULTS

497 children aged 2-17 years were included. Three groups were analyzed: 183 pre-schoolchildren aged 2-4 years, 176 schoolchildren aged 5-11 years and 138 adolescents aged 12-18 years. Positive antibodies against the S- or N-antigen of SARS-CoV-2 were detected in 86.5% of all participants (70.0% [128/183] of pre-schoolchildren, 94.3% of schoolchildren [166/176] and 98.6% of adolescents [136/138]). Among all children, 40.4% (201/497) were vaccinated against COVID-19 (pre-schoolchildren 4.4% [8/183], schoolchildren 44.3% [78/176] and adolescents 83.3% [115/138]). SARS-CoV-2 seroprevalence was lowest in pre-school. Health status and quality of life reported by the parents were very positive at the time of the survey (Summer 2022).

CONCLUSION

Age-related differences on SARS-CoV-2 sero-immunity could mainly be explained by differences in vaccination rates based on the official German vaccination recommendations as well as differences in SARS-CoV-2 infection rates in the different age groups. Health status and quality of life of almost all children were very good independent of SARS-CoV-2 infection and/or vaccination.

TRIAL REGISTRATION

German Registry for Clinical Trials Identifier Würzburg: DRKS00025546 (registration: 11.09.2021), Bochum: DRKS00022434 (registration:07.08.2020), Dresden: DRKS 00022455 (registration: 23.07.2020).

Factors influencing viral shedding time in non-severe paediatric infection with the SARS-CoV-2: a single-centre retrospective study

BACKGROUND

The aim of this study was to determine the factors influencing viral shedding time (VST) in non-severe paediatric infection with SARS-CoV-2).

METHODS

We conducted a retrospective analysis of data from 240 non-severe paediatric infection with the SARS-CoV-2. Multivariate Cox regression analysis was used to identify independent predictors associated with VST.

RESULTS

Two hundred and forty patients were included in the study. The median duration of VST was 10 days (IQR, 8-13 days). Compared with patients aged <1 year, children aged 6-12 years (adjusted HR (aHR): 1.849; 95% CI 1.031 to 3.315) and >12 years (aHR: 2.180; 95% CI 1.071 to 4.439) had shorter VST. Non-leucopenia patients (aHR: 1.431; 95% CI 1.005 to 2.038) also had a lower VST.

DISCUSSION

The results of this study show that children aged <1 year and children with leucopenia had longer SARS-CoV-2 VST. These factors should be taken into account when developing policies for the isolation of patients with COVID-19.

Kidney involvement in children during the SARS-CoV-2 Omicron variant pandemic

BACKGROUND

As the coronavirus disease-2019 (COVID-19) pandemic continues, driven by the Omicron variant, infection rates in children have recently rapidly surged compared with previous years. We aimed to investigate the presentation of kidney involvement in children after Omicron variant severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection.

METHODS

We retrospectively reviewed the medical records of pediatric patients who presented with kidney disease with a temporal relationship with COVID-19 between January and August 2022 in a single tertiary center in Korea.

RESULTS

Fifteen children presented with kidney involvement after Omicron variant infection, with a median age of 10.6 (6.8-18.3) years. None of the patients exhibited severe respiratory symptoms apart from cough and sore throat. The median time from infection to renal symptom onset was 3 (0-49) days. Among 10 patients with underlying kidney disease, six had previously been diagnosed with nephrotic syndrome (NS) that relapsed after COVID-19 infection, two with immunoglobulin A nephropathy (IgAN) experienced transient gross hematuria (GHU) with or without acute kidney injury (AKI), and two with kidney transplantation presented with AKI. Of the five patients without underlying kidney disease, one patient had NS, and the other four patients had GHU and proteinuria (PU), of whom one was eventually diagnosed with Henoch Shönlein Purpura nephritis (HSPN), and one with rhabdomyolysis. The seven patients with NS (1 new-onset, 6 relapsed) had uneventful remission with corticosteroid therapy. Apart from one patient with new-onset HSPN, GHU and PU resolved spontaneously in all affected patients, and AKI also resolved with supportive care.

CONCLUSIONS

Kidney involvement subsequent to Omicron variant COVID-19 exhibited various, but mostly mild manifestations in children.

True prevalence of long COVID in children: a narrative review

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

Acute COVID-19 in unvaccinated children without a history of previous infection during the delta and omicron periods

BACKGROUND

The Omicron variant has been the predominant severe acute respiratory syndrome coronavirus 2 variant circulating in Korea since January 2022. This study evaluated and compared the clinical characteristics of children with coronavirus disease 2019 (COVID-19) between the Delta and Omicron periods.

METHODS

The medical records of children aged < 12 years diagnosed with acute COVID-19 (<2 weeks of symptom onset) at seven university-affiliated hospitals were retrospectively reviewed. Children with a previous history of COVID-19 or vaccination were excluded. The clinical characteristics of the included children during the Delta (1 August 2021 to 15 January 2022) and Omicron (16 January to 30 June 2022) periods were compared.

RESULTS

Among the 515 children included in the study, 36 (7.0%) and 479 (93.0%) were diagnosed with COVID-19 during the Delta and Omicron periods, respectively. A total of 142 (27.6%) were hospitalized, and the hospitalization rate was higher during the Delta period than the Omicron period (91.7% vs. 22.8%, p < 0.001). The incidence of fever (p = 0.009), vomiting (p = 0.031), and seizures (p = 0.007) was higher during the Omicron period, whereas the incidence of rhinorrhea (p = 0.027) was higher during the Delta period. Clinical severity and outcomes were comparable between the two periods. During the Omicron period, 6.4% of the hospitalized children received oxygen therapy and 1.8% received intensive care.

CONCLUSION

The incidence of fever and seizures was higher during the Omicron period in pediatric patients without a history of vaccination or previous COVID-19. However, the clinical severity was similar during both periods.

Otolaryngology-related symptoms of COVID-19 in children in the post-epidemic era: a cross-sectional web-based survey study

Purpose

China adjusted and optimized its prevention and control strategies in December 2022, and it entered a new era of the coronavirus epidemic. Here, we describe the general and otolaryngology-related symptoms of coronavirus disease 2019 (COVID-19) in children during the first pandemic in the post-epidemic era, focusing on the frequency and severity of smell and taste loss, as well as the recovery process and its influencing factors.

Patients and methods

From 2 January to 7 January 2023, we conducted a cross-sectional online questionnaire survey through Questionnaire Stars in order to collect relevant information about COVID-19 in children in Shenzhen.

Results

A total of 1,247 valid questionnaires were received, with an effective response rate of 78.72%. All of the diagnoses were confirmed by nucleic acid or antigen test for COVID-19. Among the subjects, the sex ratio of male to female was more inclined to male (1.35:1), and the age was 3-16 years, with an average of 10.13 ± 2.82 years old. The most common symptoms were cough (58.24%), stuffy nose (56.18%), headache (42.09%), fatigue (40.44%), and sore throat (31.63%). Approximately 6.43% of the children reported dysosmia, the mean time of the duration of dysosmia was 5.38 ± 2.92 days, and the mean score of the severity of the dysosmia as assessed by visual analogue scale (VAS) was 4.63 ± 2.29. Approximately 13.34% reported dysgeusia, the mean time of the duration of dysgeusia was 4.77 ± 3.98 days, and the mean score of the severity of the dysgeusia as assessed by VAS was 5.12 ± 2.29. Univariate and multivariate logistic regression analysis showed that the prevalence of taste and olfactory disorders increased with age, mainly in children with severe symptoms and older children.

Conclusion

In the post-epidemic era, due to weakening of the pathogenicity of the subvariant of Omicron, overall condition of children with COVID-19 was mild, incidence of olfactory and taste disorders was low, recovery was faster, and prognosis was better. In our study, cough, runny nose, and sore throat were the most common symptoms, and the prevalence of taste and olfactory disorders increased with age, mainly in older children with severe symptoms.

Parents' intention to vaccinate their preschool children against COVID-19: Combining the health belief model and the theory of planned behavior

The vaccination rate of COVID-19 in preschool children is low, and parents' intention to vaccinate their children is also low due to multiple factors. This study aimed to establish an integrated model based on the Health Belief Model (HBM)and Theory of Planned Behavior (TPB), to explore the factors influencing parents' intention to vaccinate their preschool children with the first and second doses of COVID-19 vaccines. A total of 1264 parents of preschool children from 10 kindergartens participated in this study. Hierarchical multiple logistic regression was used to analyze the intention separately. For the integrated model with the first dose of vaccine of COVID-19, introducing the HBM variable in model 1 explained 33.98% of the variance (F = 398.71, p < .001), then upon adding the TPB variable in model 2, the explanation of variance increased to 41.93% (F = 491.94, p < .001) and parents' intention were associated with their perceived barriers, cues to action, and subjective norms. For the integrated model with the second dose of vaccine of COVID-19, introducing the HBM variable in Model 1 explained 23.76% of the variance (F = 68.82, p < .001), then upon adding the TPB variable in model 2, the explanation of variance increased to 26.67% (F = 77.24, p < .001), and parents' intention was associated with cues to action and subjective norms. The combination of the two theories improves the explanatory power of parents' intention to vaccinate their preschool children against COVID-19, and provides a basis for the development of effective interventions for vaccination of COVID-19 for preschool children.

Clinical characteristics of pediatric inpatients infected with the SARS-CoV-2 Omicron variant-a retrospective observational cohort study

Background

The children infected with the Omicron variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are at risk of progressing to severe disease. Clinical characteristics treatment measures and prognosis of these special age group of patients have not been completely understood which necessitate more researches. This study sought to analyze the clinical characteristics of children infected with the Omicron variant to provide evidences for the prevention, diagnosis and treatment of the Omicron variant infection in children.

Methods

The subjects of this study included children hospitalized for the Omicron variant at Tianjin Binhai Hospital in November 2022. The data were collected from the electronic medical record system, and the clinical characteristics of the children were analyzed. The primary endpoints included the clinical presentation, laboratory tests, virological characteristics, treatment regimen, and clinical prognosis of the patients.

Results

A total of 49 patients were enrolled, of whom 32 (65.3%) were male. The patients had a median age of 10 (interquartile range, 6-11) years, and 34.7% of the patients received 2 or more coronavirus disease 2019 (COVID-19) vaccines. The main clinical manifestations of the patients were fever (79.6%) and cough (24.5%), with a maximum temperature of 42 ℃ and a median temperature of 39 (interquartile range, 38.4-39) ℃. The proportions of neutrophils and C-reactive protein were elevated by 50.0% and 25.0%, respectively. The total percentages of white blood cells and thrombocytopenia were 12.5% and 6.3%, respectively. D-dimer was examined in 6 cases, and was elevated to 1.77 μg/mL in 1 case (16.7%), and normal in 5 cases. The liver function, kidney function, and coagulation of 9 (100%) patients were all normal. After the anti-virus, anti-inflammatory response, antipyretic, and traditional Chinese medicine treatments, all the children were cured and discharged from the hospital. There were no severe cases.

Conclusions

The main manifestations of children infected with the SARS-CoV-2 Omicron variant were fever and cough. Some children had a high fever, nasal congestion, runny nose, gastrointestinal symptoms, and rash. A proportion of 12.5% of patients have a white blood cell count less than 4×109/L, and 6.3% have thrombocytopenia. The prognosis of the child was favorable after treatment with antiviral, antipyretic, and traditional Chinese medicine.

Severity and outcomes of Omicron variant of SARS-CoV-2 compared to Delta variant and severity of Omicron sublineages: a systematic review and metanalysis

OBJECTIVES

To compare severity and clinical outcomes from Omicron as compared with the Delta variant and to compare outcomes between Omicron sublineages.

METHODS

We searched the WHO COVID-19 Research database for studies that compared clinical outcomes for patients with Omicron variant and the Delta variant, and separately Omicron sublineages BA.1 and BA.2. A random-effects meta-analysis was used to pool estimates of relative risk (RR) between variants and sublineages. Heterogeneity between studies was assessed using the I2 index. Risk of bias was assessed using the tool developed by the Clinical Advances through Research and Information Translation team.

RESULTS

Our search identified 1494 studies and 42 met the inclusion criteria. Eleven studies were published as preprints. Of the 42 studies, 29 adjusted for vaccination status; 12 had no adjustment; and for 1, the adjustment was unclear. Three of the included studies compared the sublineages of Omicron BA.1 versus BA.2. As compared with Delta, individuals infected with Omicron had 61% lower risk of death (RR 0.39, 95% CI 0.33 to 0.46) and 56% lower risk of hospitalisation (RR 0.44, 95% CI 0.34 to 0.56). Omicron was similarly associated with lower risk of intensive care unit (ICU) admission, oxygen therapy, and non-invasive and invasive ventilation. The pooled risk ratio for the outcome of hospitalisation when comparing sublineages BA.1 versus BA.2 was 0.55 (95% 0.23 to 1.30).

DISCUSSION

Omicron variant was associated with lower risk of hospitalisation, ICU admission, oxygen therapy, ventilation and death as compared with Delta. There was no difference in the risk of hospitalisation between Omicron sublineages BA.1 and BA.2.

PROSPERO REGISTRATION NUMBER

CRD42022310880.

Humoral immune responses to inactivated COVID-19 vaccine up to 1 year in children with chronic hepatitis B infection

Background

Inactivated SARS-CoV-2 vaccination has recently been approved for children aged 3-17 years in China. However, data on long-term humoral responses to inactivated vaccines in children with chronic hepatitis B (CHB) are still limited.

Methods

In this prospective observational study, CHB children after primary inactivated SARS-CoV-2 vaccines were recruited consecutively and followed up for 1 year. CHB adults from another cohort study (NCT05007665) were used as a control. The receptor-binding domain IgG antibody (anti-RBD-IgG), neutralizing antibody (NAb), neutralization against Omicron (BA2.12.1, BA.4 and BA.5), and memory B -cell (MBC) responses were evaluated.

Results

Overall, 115 CHB children and 351 CHB adults were included in this analysis. The antibody titers decreased over the first ~180 days and then plateaued up to 1 year in CHB children. However, lower and faster declines in antibody responses were observed in CHB adults. Interestingly, the seroprevalence of antibodies was still high after over 8 months in CHB children (anti-RBD-IgG [90%] and NAbs [83%]). However, neutralization against Omicron subvariants was significantly reduced in CHB children (-3.68-fold to -8.60-fold). Notably, neutralization against the BA.5 subvariant was obviously diminished in CHB children compared with adults. Moreover, CHB children had similar RBD-specific MBCs but higher RBD-specific atypical MBCs compared with adults.

Conclusion

Inactivated vaccination could elicit more robust and durable antibody responses to the wild-type SARS-CoV-2 strain in CHB children than in CHB adults but showed inferior responses to Omicron subvariants (especially to the BA.5 strain). Hence, new Omicron-related or all-in-one vaccines are needed immediately for CHB children.

[Clinical features of children with coronavirus disease 2019 in different age groups during the epidemic of Omicron variant]

OBJECTIVES

To study the differences in the clinical features of children with coronavirus disease 2019 (COVID-19) in different age groups during the epidemic of Omicron variant.

METHODS

A retrospective analysis was performed on the clinical data of 211 children with COVID-19 who were admitted to the Department of General Pediatrics, Zhongshan People's Hospital, from December 9, 2022 to January 8, 2023. According to their age, they were divided into 4 groups: 1 month-<1 year (n=84), 1-<3 years group (n=64), 3-<5 years (n=29), and ≥5 years (n=34). The above groups were compared in terms of general status, clinical features, ancillary examination results, treatment, and outcome.

RESULTS

The children aged <3 years accounted for 70.1% (148/211) of all hospitalized children with COVID-19, and the 3-<5 years group and the ≥5 years group had a significantly higher proportion of children with underlying diseases than the 1 month-<1 year group and the 1-<3 years group (P<0.05). Compared with the other three groups, the 1 month-<1 year group had significantly higher incidence rates of dyspnea, nasal congestion/nasal discharge, diarrhea and significantly lower incidence rates of convulsion and nervous system involvement (P<0.05). Moreover, compared with the other three groups, the 1 month-<1 year group had significantly higher incidence rates of increases in bile acid and creatine kinase isoenzyme and significantly lower incidence rates of decreased platelet count, increased neutrophil percentage, and decreased lymphocyte percentage (P<0.05). The 1 month-<1 year group had a significantly higher incidence rate of mild COVID-19 than the 1-<3 years group and a significantly lower incidence rate of severe/critical COVID-19 than the other three groups (P<0.05). Compared with the other three groups, the 1 month-<1 year group had a significantly higher proportion of children receiving oxygen inhalation therapy (P<0.05).

CONCLUSIONS

Children with COVID-19 in different age groups have different clinical features during the epidemic of Omicron variant, especially between the children aged 1 month to <1 year and those aged ≥1 year.

Smart Thermometer-Based Participatory Surveillance to Discern the Role of Children in Household Viral Transmission During the COVID-19 Pandemic

Importance

Children's role in spreading virus during the COVID-19 pandemic is yet to be elucidated, and measuring household transmission traditionally requires contact tracing.

Objective

To discern children's role in household viral transmission during the pandemic when enveloped viruses were at historic lows and the predominance of viral illnesses were attributed to COVID-19.

Design, Setting, and Participants

This cohort study of a voluntary US cohort tracked data from participatory surveillance using commercially available thermometers with a companion smartphone app from October 2019 to October 2022. Eligible participants were individuals with temperature measurements in households with multiple members between October 2019 and October 2022 who opted into data sharing.

Main Outcomes and Measures

Proportion of household transmissions with a pediatric index case and changes in transmissions during school breaks were assessed using app and thermometer data.

Results

A total of 862 577 individuals from 320 073 households with multiple participants (462 000 female [53.6%] and 463 368 adults [53.7%]) were included. The number of febrile episodes forecast new COVID-19 cases. Within-household transmission was inferred in 54 506 (15.4%) febrile episodes and increased from the fourth pandemic period, March to July 2021 (3263 of 32 294 [10.1%]) to the Omicron BA.1/BA.2 wave (16 516 of 94 316 [17.5%]; P < .001). Among 38 787 transmissions in 166 170 households with adults and children, a median (IQR) 70.4% (61.4%-77.6%) had a pediatric index case; proportions fluctuated weekly from 36.9% to 84.6%. A pediatric index case was 0.6 to 0.8 times less frequent during typical school breaks. The winter break decrease was from 68.4% (95% CI, 57.1%-77.8%) to 41.7% (95% CI, 34.3%-49.5%) at the end of 2020 (P < .001). At the beginning of 2022, it dropped from 80.3% (95% CI, 75.1%-84.6%) to 54.5% (95% CI, 51.3%-57.7%) (P < .001). During summer breaks, rates dropped from 81.4% (95% CI, 74.0%-87.1%) to 62.5% (95% CI, 56.3%-68.3%) by August 2021 (P = .02) and from 83.8% (95% CI, 79.2%-87.5) to 62.8% (95% CI, 57.1%-68.1%) by July 2022 (P < .001). These patterns persisted over 2 school years.

Conclusions and Relevance

In this cohort study using participatory surveillance to measure within-household transmission at a national scale, we discerned an important role for children in the spread of viral infection within households during the COVID-19 pandemic, heightened when schools were in session, supporting a role for school attendance in COVID-19 spread.

Safety and effectiveness of vaccines against COVID-19 in children aged 5-11 years: a systematic review and meta-analysis

BACKGROUND

To date, more than 761 million confirmed SARS-CoV-2 infections have been recorded globally, and more than half of all children are estimated to be seropositive. Despite high SARS-CoV-2 infection incidences, the rate of severe COVID-19 in children is low. We aimed to assess the safety and efficacy or effectiveness of COVID-19 vaccines approved in the EU for children aged 5-11 years.

METHODS

In this systematic review and meta-analysis, we included studies of any design identified through searching the COVID-19 L·OVE (living overview of evidence) platform up to Jan 23, 2023. We included studies with participants aged 5-11 years, with any COVID-19 vaccine approved by the European Medicines Agency-ie, mRNA vaccines BNT162b2 (Pfizer-BioNTech), BNT162b2 Bivalent (against original strain and omicron [BA.4 or BA.5]), mRNA-1273 (Moderna), or mRNA-1273.214 (against original strain and omicron BA.1). Efficacy and effectiveness outcomes were SARS-CoV-2 infection (PCR-confirmed or antigen-test confirmed), symptomatic COVID-19, hospital admission due to COVID-19, COVID-19-related mortality, multisystem inflammatory syndrome in children (MIS-C), and long-term effects of COVID-19 (long COVID or post-COVID-19 condition as defined by study investigators or per WHO definition). Safety outcomes of interest were serious adverse events, adverse events of special interest (eg, myocarditis), solicited local and systemic events, and unsolicited adverse events. We assessed risk of bias and rated the certainty of evidence (CoE) using the Grading of Recommendations Assessment, Development and Evaluation approach. This study was prospectively registered with PROSPERO, CRD42022306822.

FINDINGS

Of 5272 screened records, we included 51 (1·0%) studies (n=17 [33%] in quantitative synthesis). Vaccine effectiveness after two doses against omicron infections was 41·6% (95% CI 28·1-52·6; eight non-randomised studies of interventions [NRSIs]; CoE low), 36·2% (21·5-48·2; six NRSIs; CoE low) against symptomatic COVID-19, 75·3% (68·0-81·0; six NRSIs; CoE moderate) against COVID-19-related hospitalisations, and 78% (48-90, one NRSI; CoE very low) against MIS-C. Vaccine effectiveness against COVID-19-related mortality was not estimable. Crude event rates for deaths in unvaccinated children were less than one case per 100 000 children, and no events were reported for vaccinated children (four NRSIs; CoE low). No study on vaccine effectiveness against long-term effects was identified. Vaccine effectiveness after three doses was 55% (50-60; one NRSI; CoE moderate) against omicron infections, and 61% (55-67; one NRSI; CoE moderate) against symptomatic COVID-19. No study reported vaccine efficacy or effectiveness against hospitalisation following a third dose. Safety data suggested no increased risk of serious adverse events (risk ratio [RR] 0·83 [95% CI 0·21-3·33]; two randomised controlled trials; CoE low), with approximately 0·23-1·2 events per 100 000 administered vaccines reported in real-life observations. Evidence on the risk of myocarditis was uncertain (RR 4·6 [0·1-156·1]; one NRSI; CoE low), with 0·13-1·04 observed events per 100 000 administered vaccines. The risk of solicited local reactions was 2·07 (1·80-2·39; two RCTs; CoE moderate) after one dose and 2·06 (1·70-2·49; two RCTs; CoE moderate) after two doses. The risk of solicited systemic reactions was 1·09 (1·04-1·16; two RCTs; CoE moderate) after one dose and 1·49 (1·34-1·65; two RCTs; CoE moderate) after two doses. The risk of unsolicited adverse events after two doses (RR 1·21 [1·07-1·38]; CoE moderate) was higher among mRNA-vaccinated compared with unvaccinated children.

INTERPRETATION

In children aged 5-11 years, mRNA vaccines are moderately effective against infections with the omicron variant, but probably protect well against COVID-19 hospitalisations. Vaccines were reactogenic but probably safe. Findings of this systematic review can serve as a basis for public health policy and individual decision making on COVID-19 vaccination in children aged 5-11 years.

FUNDING

German Federal Joint Committee.

Vaccination status for mild and asymptomatic infections with SARS-CoV-2 Omicron BA.2 variant in Shanghai

This study aimed to evaluate the effects of different vaccine regimens on mild and asymptomatic infections with SARS-CoV-2 Omicron BA.2 variant in Shanghai. All asymptomatic patients and those with mild symptoms of Omicron infections were recruited from three major Fangcang shelter hospitals between March 26, 2022 and May 20, 2022. Nucleic acid for SARS-CoV-2 by real-time reverse-transcription polymerase chain reaction methods in nasopharyngeal swabs was assessed every day during the hospitalization. The value of cycle threshold lower than 35 was considered as positive result of SARS-CoV-2. A total of 214 592 cases were included in this study. The proportion of the asymptomatic patients was 76.90% and 23.10% of the recruited patients had mild symptoms. The median (interquartile range [IQR]: 25-75) duration of viral shedding (DVS) was 7 (5-10) days among all participants. The DVS varied greatly among different age groups. Children and the elderly had longer DVS compared with the adults. The booster shot of inactivated vaccine contributed to the shorter DVS in patients aged ≥70 years compared with the unvaccinated patients (8 [6-11] vs. 9 [6-12] days, p = 0.002]. Full inactivated vaccine regimen contributed to the shorter DVS in patients aged 3-6 years (7 [5-9] vs. 8 [5-10] days, p = 0.001]. In conclusion, the full inactivated vaccine regimen on children aged 3-6 years and booster inactivated vaccine regimen on the elderly aged ≥70 years appeared to be effective in reducing DVS. The booster vaccine regimen should be rigorously promoted and implemented.

Intranasal infection by SARS-CoV-2 Omicron variants can induce inflammatory brain damage in newly-weaned hamsters

SummaryIntranasal infection of newly-weaned Syrian hamsters by SARS-CoV-2 Omicron variants can lead to brain inflammation and neuron degeneration with detectable low viral load and sparse expression of viral nucleoprotein.AbstractChildren infected by SARS-CoV-2 Omicron variant may develop neurological complications. To study the pathogenesis in the growing brain, we intranasally challenged newly-weaned or mature hamsters with SARS-CoV-2 Omicron BA.2, BA.5 or Delta variant. Omicron BA.2 and Delta infection produced a significantly lower viral load in the lung tissues of newly-weaned than mature hamsters despite comparable histopathological damages. Newly-weaned hamsters had higher brain viral load, significantly increased cerebrospinal fluid concentration of TNF-α and CXCL10 and inflammatory damages including mild meningitis and parenchymal vascular congestion, despite sparse expression of nucleocapsid antigen in brain cells. Furthermore, 63.6% (28/44) of all SARS-CoV-2 infected newly-weaned hamsters showed microgliosis in olfactory bulb, cerebral cortex and hippocampus. In infected mature hamsters, microgliosis were observed mainly in olfactory bulb and olfactory cortex of 35.3% (12/34) of their brains. Neuronal degeneration was found in 75% (33/44) of newly-weaned hamsters affecting multiple regions including olfactory bulb, olfactory cortex, midbrain cortex and hippocampus, while such changes were mainly observed in hippocampus of mature hamsters. Importantly, similar brain histopathology was observed in Omicron BA.5 infected newly-weaned hamsters. Our study suggested that SARS-CoV-2 may affect the brain at young age. This kind of brain involvement and histological changes are not virus variant or subvariant specific. Incidentally, moderate amount of eosinophilic infiltration was observed in the mucosa of nasal turbinate and trachea of newly-weaned hamsters infected by Omicron BA.2 and BA.5 but not Delta variant. This histological finding is consistent with the higher incidence of laryngotracheobronchitis in young children infected by the Omicron variant.