SARS-CoV-2 vaccine testing and trials in the pediatric population: biologic, ethical, research, and implementation challenges

COVID-19 Vaccines in the Pediatric Population: A Focus on Cardiac Patients

Due to the deleterious global impact of the COVID-19 pandemic, tremendous effort has been invested in the development of vaccines against the virus. Vaccine candidates are first tested in adult populations, a number of which have been approved for EUL by the WHO, and are in use across the USA and MENA region. The question remains whether these (or other) vaccines should be recommended to a neonatal, pediatric, and/or adolescent cohort. Incidence and severity of COVID-19 infection are low in pediatric, neonatal, and adolescent patients. Since both overall incidence and severity are lower in children than in adults, safety is an important consideration in vaccine approval for these age groups, in addition to efficacy and a decreased risk of transmission. The following review discusses vaccine immunology in children aged 0-18 years, with emphasis on the negative impact of the COVID-19 pandemic on the lives of children, considerations for pediatric vaccine approval, and available vaccines for pediatric cohorts along with a breakdown of the efficacy, advantages, and disadvantages for each. This review also contains current and future perspectives, as well as a section on the cardiovascular implications and related dynamics of pediatric COVID-19 vaccination.

Impact of a booster dose on SARS-CoV2 mRNA vaccine-specific humoral-, B- and T cell immunity in pediatric stem cell transplant recipients

Stem cell transplant recipients (SCTR) are imperiled to increased risks after SARS-CoV2 infection, supporting the need for effective vaccination strategies for this vulnerable group. With respect to pediatric patients, data on immunogenicity of SARS-CoV2 mRNA-based vaccination is limited. We therefore comprehensively examined specific humoral, B- and T cell responses in a cohort of 2-19 year old SCTR after the second and third vaccine dose. Only after booster vaccination, transplant recipients reached similar levels of vaccine-specific IgG, IgA and neutralizing antibodies against omicron variant as age-matched controls. Although frequencies of SARS-CoV2 specific B cells increased after the third dose, they were still fourfold reduced in patients compared to controls. Overall, the majority of individuals enrolled mounted SARS-CoV2 Spike protein-specific CD4+ T helper cell responses with patients showing significantly higher portions than controls after the third dose. With respect to functionality, however, SCTR were characterized by reduced frequencies of specific interferon gamma producing CD4+ T cells, along with an increase in IL-2 producers. In summary, our data identify distinct quantitative and qualitative impairments within the SARS-CoV2 vaccination specific B- and CD4+ T cell compartments. More importantly, humoral analyses highlight the need for a booster vaccination of SCTR particularly for development of neutralizing antibodies.

Clinical Epidemiology of Pediatric Coronavirus Disease 2019 and its Postacute Sequelae

The coronavirus disease 2019 (COVID-19) pandemic has affected individuals of all ages across. Although children generally experience a benign illness from COVID-19, the emergence of novel variants of the virus has resulted in significant changes in the morbidity and mortality rates for this age group. Currently, COVID-19 is the eighth leading cause of pediatric deaths in the United States. In addition to acute respiratory illness, some children can develop a severe postinfectious condition known as a multisystem inflammatory syndrome in children, which can progress to rapid-onset cardiogenic shock. Recovery from COVID-19 can also be slow for some children, resulting in persistent or reoccurring symptoms for months, commonly referred to as long COVID. These postinfectious sequelae are often distressing for children and their parents, can negatively impact the quality of life, and impose a considerable burden on the health care system. In this article, we review the clinical epidemiology of pediatric COVID-19 and outline the management considerations for its acute and postacute manifestations.

Does the light at the end of the tunnel shine for everyone? The need for early paediatric participation in vaccine trials during infectious pandemics

While most of the mortality associated with severe acute respiratory syndrome coronavirus 2 has been in elderly populations and adults with significant medical comorbidities, there has been death and morbidity in paediatric populations. As vaccine trial data is released to the public, many people look to the future with hope ; with good vaccine uptake there is the opportunity to reduce the spread of infectious pandemics. Initial vaccine trials were completed with adults and were expanded to include paediatric populations delaying paediatric COVID-19 vaccine initiatives. The exclusion of children from initial vaccine trials during a pandemic is not morally justifiable and fosters distrust with the pharmaceutical and medical industries and inevitably postpones vaccinating children when there is a surplus of available vaccines. The delayed vaccination of children under twelve may have significant public health and economic consequences as there may be ongoing viral transmission in the context of reopening strategies. The safety and efficacy of these candidate vaccines in children should be assessed expeditiously so that distribution to vulnerable paediatric populations is not impacted. Vaccine uptake compliance in the general population is important in establishing herd immunity and ensuring that there is thorough scientific evidence to support vaccination for children is important in establishing community trust.

The effectiveness of COVID-19 vaccines in reducing the incidence, hospitalization, and mortality from COVID-19: A systematic review and meta-analysis

Background

Vaccination, one of the most important and effective ways of preventing infectious diseases, has recently been used to control the COVID-19 pandemic. The present meta-analysis study aimed to evaluate the effectiveness of COVID-19 vaccines in reducing the incidence, hospitalization, and mortality from COVID-19.

Methods

A systematic search was performed independently in Scopus, PubMed via Medline, ProQuest, and Google Scholar electronic databases as well as preprint servers using the keywords under study. We used random-effect models and the heterogeneity of the studies was assessed using I ² and χ² statistics. In addition, the Pooled Vaccine Effectiveness (PVE) obtained from the studies was calculated by converting based on the type of outcome.

Results

A total of 54 studies were included in this meta-analysis. The PVE against SARS-COV 2 infection were 71% [odds ratio (OR) = 0.29, 95% confidence intervals (CI): 0.23-0.36] in the first dose and 87% (OR = 0.13, 95% CI: 0.08-0.21) in the second dose. The PVE for preventing hospitalization due to COVID-19 infection was 73% (OR = 0.27, 95% CI: 0.18-0.41) in the first dose and 89% (OR = 0.11, 95% CI: 0.07-0.17) in the second dose. With regard to the type of vaccine, mRNA-1273 and combined studies in the first dose and ChAdOx1 and mRNA-1273 in the second dose had the highest effectiveness in preventing infection. Regarding the COVID-19-related mortality, PVE was 68% (HR = 0.32, 95% CI: 0.23-0.45) in the first dose and 92% (HR = 0.08, 95% CI: 0.02-0.29) in the second dose.

Conclusion

The results of this meta-analysis indicated that vaccination against COVID-19 with BNT162b2 mRNA, mRNA-1273, and ChAdOx1, and also their combination, was associated with a favorable effectiveness against SARS-CoV2 incidence rate, hospitalization, and mortality rate in the first and second doses in different populations. We suggest that to prevent the severe form of the disease in the future, and, in particular, in the coming epidemic picks, vaccination could be the best strategy to prevent the severe form of the disease.

Systematic review registration

PROSPERO International Prospective Register of Systematic Reviews: http://www.crd.york.ac.uk/PROSPERO/, identifier [CRD42021289937].

COVID-19 Vaccine Clinical Trials: A Bird’s Eye Perspective

Several Phase-III clinical studies investigating vaccine safety and effectiveness have been published a year following the first breakout of the COVID-19 pandemic. These vaccine candidates were produced using a variety of vaccination technologies, including mRNA, recombinant protein, adenoviral vector, and inactivated virus-based platforms, by various research organizations and pharmaceutical firms. Despite many successful clinical studies, participants are restricted by trial inclusion and exclusion criteria, geographic location, and the current state of the virus epidemic. Many concerns remain, particularly for specific populations such as the elderly, women who are pregnant or nursing, and teenagers. Vaccine effectiveness against asymptomatic infection and particular viral variations, on the other hand, is still largely unclear. This review will focus on vaccination candidates that have completed Phase-III clinical trials and will examine the scientific evidence that has been gathered so far for these vaccine candidates for various subgroups of individuals and virus variations.

Narrative Review: Addressing Covid-19 Vaccine Concerns in Special and Vulnerable Populations

Public health advocates and healthcare professionals (HCPs) have been challenged with vaccine hesitancy and addressing misinformation. In order for HCPs and pharmacists, in particular, to serve as effective stewards of COVID-19 vaccine science in the interest of the public good, it is imperative for HCPs to appreciate the various factors contributing to vaccine hesitancy and vaccine distrust. A PubMed search was performed and relevant articles on COVID-19 vaccine in populations of interest were included. Information from health agencies, such as the Centers for Disease Control and Prevention (CDC) as well as established professional health societies was incorporated for guidance. This review focuses on COVID-19 vaccine concerns in the populations of children, pregnancy and lactation, immunocompromised, and religious and ethnic disparities. We also discuss post emergency use authorization experience with respect to vaccine safety including annotations on Guillain-Barré Syndrome, myocarditis and pericarditis, and thrombosis with thrombocytopenia syndrome.

Global caregiver concerns of SARS-CoV-2 vaccination in children with cancer: a cross-sectional mixed-methods study

The objective of this study was to understand global caregiver concerns about SARS-CoV-2 vaccination for children with cancer and to provide healthcare providers with guidance to support parental decision-making. A co-designed cross-sectional mixed-methods survey was distributed to primary caregivers of children with cancer globally between April and May 2021 via several media. Caregivers were asked to rate the importance of vaccine-related questions and the median scores were ranked. Principal Component Analysis was conducted to identify underlying dimensions of caregiver concerns by World Bank income groups. Content analysis of free-text responses was conducted and triangulated with the quantitative findings. 627 caregivers from 22 countries responded to the survey with 5.3% (n = 67) responses from low-and-middle-income countries (LMIC). 184 caregivers (29%) provided free-text responses. Side effects and vaccine safety were caregivers' primary concerns in all countries. Questions related to logistics were of concern for caregivers in LMIC. A small minority of caregivers (n = 17) did not consider the survey questions important; free-text analysis identified these parents as vaccine hesitant, some of them quoting safety and side effects as main reasons for hesitancy. Healthcare providers and other community organizations globally need to provide tailored information about vaccine safety and effectiveness in pediatric oncology settings. Importantly, continued efforts are imperative to reduce global inequities in logistical access to vaccines, particularly in LMIC.

Adolescent COVID-19 Vaccine Decision-Making among Parents in Southern California

Adolescent COVID-19 vaccination has stalled at 53% in the United States. Vaccinating adolescents remains critical to preventing the continued transmission of COVID-19, the emergence of variants, and rare but serious disease in children, and it is the best preventive measure available to return to in-person schooling. We investigated parent–adolescent COVID-19 vaccine decision-making. Between 24 February and 15 March 2021, we conducted surveys and 12 focus groups with 46 parent–adolescent dyads in Southern California. Parents and adolescents completed a survey prior to participation in a focus group discussion, which focused on exploring COVID-19 vaccine acceptance or uncertainty and was guided by the 5C vaccine hesitancy model. Parents uncertain about vaccinating adolescents expressed low vaccine confidence and high COVID-19 disease risk complacency. Parents who accepted COVID-19 vaccination for adolescents expressed high confidence in health authority vaccine recommendations, high perceived COVID-19 risk, and collective responsibility to vaccinate children. Additionally, unique pandemic-related factors of vaccine acceptance included vaccinating for emotional health, resuming social activities, and vaccine mandates. Among parents, 46% were willing to vaccinate their adolescent, 11% were not, and 43% were unsure. Among adolescents, 63% were willing to vaccinate. Despite vaccine availability, 47% of adolescents remain unvaccinated against COVID-19. Factors associated with vaccine uncertainty and acceptability inform health care practitioner, school, community, and public health messaging to reach parents and adolescents.

Barriers and facilitators of childhood COVID-19 vaccination among parents: A systematic review

BACKGROUND

The acceptance of vaccination against COVID-19 among parents of young children plays a significant role in controlling the current pandemic. A wide range of factors that influence vaccine hesitancy in adults has been reported worldwide, but less attention has been given to COVID-19 vaccination among children. Vaccine hesitancy is considered a major challenge in achieving herd immunity, and it is more challenging among parents as they remain deeply concerned about their child's health. In this context, a systematic review of the current literature is inevitable to assess vaccine hesitancy among parents of young children to ensure a successful ongoing vaccination program.

METHOD

A systematic search of peer-reviewed English literature indexed in Google Scholar, PubMed, Embase, and Web of science was performed using developed keywords between 1 January 2020 and August 2022. This systematic review included only those studies that focused on parental concerns about COVID-19 vaccines in children up to 12 years without a diagnosis of COVID-19. Following PRISMA guidelines, a total of 108 studies were included. The quality appraisal of the study was performed by Newcastle-Ottawa Scale (NOS).

RESULTS

The results of 108 studies depict that vaccine hesitancy rates differed globally with a considerably large number of factors associated with it. The highest vaccine hesitancy rates among parents were reported in a study from the USA (86.1%) and two studies from Saudi Arabia (>85%) and Turkey (89.6%). Conversely, the lowest vaccine hesitancy rates ranging from 0.69 and 2% were found in two studies from South Africa and Switzerland, respectively. The largest study (n = 227,740) was conducted in Switzerland while the smallest sample size (n = 12) was represented by a study conducted in the USA. The most commonly reported barriers to childhood vaccination were mothers' lower education level (N = 46/108, 43%), followed by financial instability (N = 19/108, 18%), low confidence in new vaccines (N = 13/108, 12%), and unmonitored social media platforms (N = 5/108, 4.6%). These factors were significantly associated with vaccine refusal among parents. However, the potential facilitators for vaccine uptake among respondents who intended to have their children vaccinated include higher education level (N = 12/108, 11%), followed by information obtained through healthcare professionals (N = 9/108, 8.3%) and strong confidence in preventive measures taken by the government (N = 5/81, 4.6%).

CONCLUSION

This review underscores that parents around the globe are hesitant to vaccinate their kids against COVID-19. The spectrum of factors associated with vaccine hesitancy and uptake varies across the globe. There is a dire need to address vaccine hesitancy concerns regarding the efficacy and safety of approved vaccines. Local context is inevitable to take into account while developing programs to reduce vaccine hesitancy. There is a dire need to devise strategies to address vaccine hesitancy among parents through the identification of attributing factors.

SARS-CoV-2 acquisition and immune pathogenesis among school-aged learners in four diverse schools

BACKGROUND

Understanding SARS-CoV-2 infection in children is necessary to reopen schools safely.

METHODS

We measured SARS-CoV-2 infection in 320 learners [10.5 ± 2.1 (sd); 7-17 y.o.] at four diverse schools with either remote or on-site learning. Schools A and B served low-income Hispanic learners; school C served many special-needs learners, and all provided predominantly remote instruction. School D served middle- and upper-income learners, with predominantly on-site instruction. Testing occurred in the fall (2020), and 6-8 weeks later during the fall-winter surge (notable for a tenfold increase in COVID-19 cases). Immune responses and mitigation fidelity were also measured.

RESULTS

We found SARS-CoV-2 infections in 17 learners only during the surge. School A (97% remote learners) had the highest infection (10/70, 14.3%, p < 0.01) and IgG positivity rates (13/66, 19.7%). School D (93% on-site learners) had the lowest infection and IgG positivity rates (1/63, 1.6%). Mitigation compliance [physical distancing (mean 87.4%) and face-covering (91.3%)] was remarkably high at all schools. Documented SARS-CoV-2-infected learners had neutralizing antibodies (94.7%), robust IFN-γ + T cell responses, and reduced monocytes.

CONCLUSIONS

Schools can implement successful mitigation strategies across a wide range of student diversity. Despite asymptomatic to mild SARS-CoV-2 infection, children generate robust humoral and cellular immune responses.

IMPACT

Successful COVID-19 mitigation was implemented across a diverse range of schools. School-associated SARS-CoV-2 infections reflect regional rates rather than remote or on-site learning. Seropositive school-aged children with asymptomatic to mild SARS-CoV-2 infections generate robust humoral and cellular immunity.

The Association Between Risk Perception and COVID-19 Vaccine Hesitancy for Children Among Reproductive Women in China: An Online Survey

Background: This study aimed to explore the association between risk perception and coronavirus disease 2019 (COVID-19) vaccine hesitancy among reproductive women in China to supplement limited studies in this area. Methods: From December 14, 2020, to January 31, 2021, an anonymous cross-sectional online survey was conducted on COVID-19 vaccine hesitancy for children among reproductive women in China. We assessed risk perception, including perceived susceptibility, severity, barriers, and benefits using the health belief model, and then classified each variable into three groups (low, moderate, and high) based on tertiles. Information on sociodemographic characteristics, health status, and knowledge of COVID-19 was also collected. The Pearson χ²-test was used to compare vaccine hesitancy among the above mentioned factors. Logistic regression models were used to calculate the adjusted odds ratio (aOR) of risk perception related to vaccine hesitancy after controlling for the above covariates. Results: Among 3,011 reproductive women, 8.44% (95%CI: 7.44. 9.43) had COVID-19 vaccine hesitancy. Vaccine hesitancy was observed more in women who lived in eastern China (11.63%), aged >45 years (12.00%), had a lower than high school education level (12.77%), and a low score on knowledge of COVID-19 (12.22%). Vaccine hesitancy was associated with lower perceived susceptibility (moderate: aOR = 1.72, 95%CI: 1.17-2.54, P = 0.0061; low: aOR = 2.44, 95%CI: 1.60-3.70, P < 0.0001), high perceived barriers (aOR = 2.86, 95%CI: 1.57-5.22, P < 0.0001), and lower perceived benefit (moderate: aOR = 3.29, 95%CI: 2.30-4.70, P < 0.0001; low: aOR = 4.59, 95%CI: 2.98-7.07, P < 0.0001), but not with perceived severity. Conclusions: Although the proportion of COVID-19 vaccine hesitancy for children among Chinese reproductive women was <1 out of 10, to improve COVID-19 vaccine hesitancy, our findings suggest that tailored public health measures are needed to increase perceived susceptibility and benefit, and decrease perceived barriers among reproductive women.

A systematic review of effectiveness of BNT162b2 mRNA and ChAdOx1 adenoviral vector COVID-19 vaccines in the general population

BACKGROUND

High effectiveness of COVID-19 vaccines is essential for the pandemic control. This study systematically reviewed available evidence on effectiveness of ChAdOx1 and BNT162b2 vaccines in the general population, for improved vaccine policies and strategies.

MAIN BODY OF THE ABSTRACT

Using several keywords, a search of Scopus, PubMed, Google scholar and Hinari databases was conducted from December 1, 2020 to June 9, 2021. Eligible studies comprising original studies reporting effectiveness of the vaccines, were included following PRISMA guidelines. Individual studies were assessed for quality using National Heart, Lung and Blood Institute quality assessment tool. A total of 1766 titles were retrieved and 11 were included, out of which only 5 were peer-reviewed. Although data availability was limited, studies suggest equivalent effectiveness of BNT162b2 and ChAdOx1 COVID-19 vaccine against SARS-CoV-2 infection and COVID-19 related morbidity and mortality. Vaccine effectiveness increased steadily to about 35 days, with an enhanced effectiveness following the second dose.

SHORT CONCLUSION

BNT162 and ChAdOx1 vaccines were associated with equivalent and high effectiveness which increased with time and a second dose in the general population. This encourages continued practice of other preventive measures, particularly during the first week of vaccination, and reinforces the need for a second dose.

Attitudes toward the SARS-CoV-2 Vaccine: Results from the Saudi Residents' Intention to Get Vaccinated against COVID-19 (SRIGVAC) Study

Vaccine uptake could influence vaccination efforts to control the widespread COVID-19 pandemic; however, little is known about vaccine acceptance in Saudi Arabia. The present study aimed to assess the Saudi public's intent to get vaccinated against COVID-19 and explore the associated demographic determinants of their intentions as well as the reasons for vaccine hesitancy. A cross-sectional, web-based survey was distributed to public individuals in Saudi Arabia between 25 December 2020 and 15 February 2021. Participants were asked if they were willing to get vaccinated, and the responses, along with demographic data were entered into a multinomial logistic regression model to assess the relative risk ratio (RRR) for responding "no" or "unsure" versus "yes". Among 3048 participants (60.1% female, 89.5% Saudi), 52.9% intend to get vaccinated, 26.8% were unsure, and 20.3% refused vaccination. Vaccine hesitancy was significantly higher among females (RRR = 2.70, p < 0.0001) and those who had not been recently vaccinated for influenza (RRR = 2.63, p < 0.0001). The likelihood was lower among Saudis (RRR = 0.49, p < 0.0001), those with less than a secondary education (RRR = 0.16, p < 0.0001), perceived risks of COVID-19, and residents of the southern region (RRR = 0.46, p < 0.0001). The most often cited reasons for hesitancy were short clinical testing periods and concerns about adverse events or effectiveness. Vaccine hesitancy is mediated by many demographic factors and personal beliefs. To address vaccine-related concerns and amend deeply rooted health beliefs, communication should provide transparent information.

SARS-CoV-2 mRNA Vaccine Attitudes as Expressed in U.S. FDA Public Commentary: Need for a Public-Private Partnership in a Learning Immunization System

As part of the U.S. Food and Drug Administration COVID-19 vaccine review process, public commentary was solicited offering an opportunity to reflect on vaccine attitudes that may impact the uptake of coronavirus vaccines. We identified themes in the commentary that highlighted the safety, efficacy, ethics, and trustworthiness and transparency regarding the novel mRNA COVID-19 vaccines. A “Learning Immunization System” model is proposed to optimize public, private, and academic partnerships relating to vaccine development and implementation.

Safety, Immunogenicity, and Efficacy of the BNT162b2 Covid-19 Vaccine in Adolescents

BACKGROUND

Until very recently, vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) had not been authorized for emergency use in persons younger than 16 years of age. Safe, effective vaccines are needed to protect this population, facilitate in-person learning and socialization, and contribute to herd immunity.

METHODS

In this ongoing multinational, placebo-controlled, observer-blinded trial, we randomly assigned participants in a 1:1 ratio to receive two injections, 21 days apart, of 30 μg of BNT162b2 or placebo. Noninferiority of the immune response to BNT162b2 in 12-to-15-year-old participants as compared with that in 16-to-25-year-old participants was an immunogenicity objective. Safety (reactogenicity and adverse events) and efficacy against confirmed coronavirus disease 2019 (Covid-19; onset, ≥7 days after dose 2) in the 12-to-15-year-old cohort were assessed.

RESULTS

Overall, 2260 adolescents 12 to 15 years of age received injections; 1131 received BNT162b2, and 1129 received placebo. As has been found in other age groups, BNT162b2 had a favorable safety and side-effect profile, with mainly transient mild-to-moderate reactogenicity (predominantly injection-site pain [in 79 to 86% of participants], fatigue [in 60 to 66%], and headache [in 55 to 65%]); there were no vaccine-related serious adverse events and few overall severe adverse events. The geometric mean ratio of SARS-CoV-2 50% neutralizing titers after dose 2 in 12-to-15-year-old participants relative to 16-to-25-year-old participants was 1.76 (95% confidence interval [CI], 1.47 to 2.10), which met the noninferiority criterion of a lower boundary of the two-sided 95% confidence interval greater than 0.67 and indicated a greater response in the 12-to-15-year-old cohort. Among participants without evidence of previous SARS-CoV-2 infection, no Covid-19 cases with an onset of 7 or more days after dose 2 were noted among BNT162b2 recipients, and 16 cases occurred among placebo recipients. The observed vaccine efficacy was 100% (95% CI, 75.3 to 100).

CONCLUSIONS

The BNT162b2 vaccine in 12-to-15-year-old recipients had a favorable safety profile, produced a greater immune response than in young adults, and was highly effective against Covid-19. (Funded by BioNTech and Pfizer; C4591001 ClinicalTrials.gov number, NCT04368728.).

SARS-CoV-2 vaccines elicit durable immune responses in infant rhesus macaques

The inclusion of infants in the SARS-CoV-2 vaccine roll-out is important to prevent severe complications of pediatric SARS-CoV-2 infections and to limit transmission and could possibly be implemented via the global pediatric vaccine schedule. However, age-dependent differences in immune function require careful evaluation of novel vaccines in the pediatric population. Toward this goal, we assessed the safety and immunogenicity of two SARS-CoV-2 vaccines. Two groups of 8 infant rhesus macaques (RMs) were immunized intramuscularly at weeks 0 and 4 with stabilized prefusion SARS-CoV-2 S-2P spike (S) protein encoded by mRNA encapsulated in lipid nanoparticles (mRNA-LNP) or the purified S protein mixed with 3M-052, a synthetic TLR7/8 agonist in a squalene emulsion (Protein+3M-052-SE). Neither vaccine induced adverse effects. Both vaccines elicited high magnitude IgG binding to RBD, N terminus domain, S1, and S2, ACE2 blocking activity, and high neutralizing antibody titers, all peaking at week 6. S-specific memory B cells were detected by week 4 and S-specific T cell responses were dominated by the production of IL-17, IFN-γ, or TNF-α. Antibody and cellular responses were stable through week 22. The immune responses for the mRNA-LNP vaccine were of a similar magnitude to those elicited by the Moderna mRNA-1273 vaccine in adults. The S-2P mRNA-LNP and Protein-3M-052-SE vaccines were well-tolerated and highly immunogenic in infant RMs, providing proof-of concept for a pediatric SARS-CoV-2 vaccine with the potential for durable immunity that might decrease the transmission of SARS-CoV-2 and mitigate the ongoing health and socioeconomic impacts of COVID-19.

SARS-CoV-2 Acquisition and Immune Pathogenesis Among School-Aged Learners in Four Diverse Schools

Background

Understanding SARS-CoV-2 infection in children is necessary to reopen schools safely.

Methods

We measured SARS-CoV-2 infection in 320 learners [10.5 ± 2.1(sd); 7-17 y.o.] at four diverse schools with either remote or on-site learning. Schools A and B served low-income Hispanic learners; school C served many special-needs learners; and all provided predominantly remote instruction. School D served middle- and upper-income learners, with predominantly on-site instruction. Testing occurred in the fall (2020), and 6-8 weeks later during the fall-winter surge (notable for a tenfold increase in COVID-19 cases). Immune responses and mitigation fidelity were also measured.

Results

We found SARS-CoV-2 infections in 17 learners only during the surge. School A (97% remote learners) had the highest infection (10/70, 14.3%, p<0.01) and IgG positivity rates (13/66, 19.7%). School D (93% on-site learners) had the lowest infection and IgG positivity rates (1/63, 1.6%). Mitigation compliance [physical distancing (mean 87.4%) and face covering (91.3%)] was remarkably high at all schools. Documented SARS-CoV-2-infected learners had neutralizing antibodies (94.7%), robust IFN-γ+ T cell responses, and reduced monocytes.

Conclusion

Schools can implement successful mitigation strategies across a wide range of student diversity. Despite asymptomatic to mild SARS-CoV-2 infection, children generate robust humoral and cellular immune responses.

Key Points

Successful COVID-19 mitigation was implemented across a diverse range of schools.School-associated SARS-CoV-2 infections reflect regional rates rather than remote or on-site learning.Seropositive school-aged children with asymptomatic to mild SARS-CoV-2 infections generate robust humoral and cellular immunity.

Review of Covid-19 vaccine clinical trials - A puzzle with missing pieces

A year after the initial outbreak of Covid-19 pandemic, several Phase III clinical trials investigating vaccine safety and efficacy have been published. These vaccine candidates were developed by different research groups and pharmaceutical companies with various vaccine technologies including mRNA, recombinant protein, adenoviral vector and inactivated virus-based platforms. Despite numerous successful clinical trials, participants enrolled in these trials are limited by trial inclusion and exclusion criteria, geographic location and viral outbreak situation. Many questions still remain, especially for specific subgroups, including the elderly, females with pregnancy and breastfeeding status, and adolescents. At the same time, vaccine efficacy towards asymptomatic infection and specific viral variants are still largely unknown. This review will cover vaccine candidates with Phase III clinical trial data released and discuss the scientific data available so far for these vaccine candidates for different subgroups of people and different viral variants.

SARS-CoV-2 Vaccination in Children and Adolescents-A Joint Statement of the European Academy of Paediatrics and the European Confederation for Primary Care Paediatricians

Stopping the COVID-19 pandemic and its socio-economic consequences is only possible with a multifaceted strategy, including mass vaccination. Studies have been conducted mainly in adults, and data on the pediatric population is relatively limited. However, it appears that vaccination in children and adolescents is highly effective and safe. Despite the apparent benefits of vaccinating this age group, there are some medical and ethical concerns. Based on the above considerations, the European Academy of Paediatrics (EAP) and the European Confederation of Primary Care Pediatricians (ECPCP) assessed the current situation and presented recommendations for international and national authorities, pediatricians, and pediatric societies regarding vaccination against SARS-CoV-2 in children and adolescents.