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).

Somatosensory abnormalities after infection with SARS-CoV-2 – A prospective case-control study in children and adolescents

Background Long-term neurological complaints after SARS-CoV-2 infection occur in 4–66% of children and adolescents. Controlled studies on the integrity of the peripheral nerve system are scarce. Therefore, we examined the somatosensory function in children and adolescents after SARS-CoV-2 infection in a case-control study compared with age-matched individuals. Materials and Methods Eighty-one subjects after SARS-CoV-2 infection (n = 44 female, 11.4 ± 3.5 years, n = 75 SARS-CoV-2 seropositive, n = 6 PCR positive during infection and SARS-CoV-2 seronegative at the time point of study inclusion, n = 47 asymptomatic infection) were compared to 38 controls without SARS-CoV-2 infection (26 female, 10.3 ± 3.4 years, n = 15 with other infection within last 6 months). After standardised interviews and neurological examinations, large fibre (tactile and vibration detection thresholds) and small fibre (cold and warm detection thresholds, paradoxical heat sensation) functions were assessed on both feet following a validated protocol. After z-transformation of all values, all participants were compared to published reference values regarding the number of abnormal results. Additionally, the mean for all sensory parameters values of both study groups were compared to an ideal healthy population (with z-value 0 ± 1), as well as with each other, as previously described. Statistical analyses: t-test, Chi-squared test, and binominal test. Findings None of the controls, but 27 of the 81 patients (33%, p < 0.001) reported persistent complaints 2.7 ± 1.9 (0.8–8.5) months after SARS-CoV-2 infection, most often reduced exercise capacity (16%), fatigue (13%), pain (9%), or paraesthesia (6%). Reflex deficits or paresis were missing, but somatosensory profiles showed significantly increased detection thresholds for thermal (especially warm) and vibration stimuli compared to controls. Approximately 36% of the patients after SARS-CoV-2, but none of the controls revealed an abnormal sensory loss in at least one parameter (p < 0.01). Sensory loss was characterised in 26% by large and 12% by small fibre dysfunction, the latter appearing more frequently in children with prior symptomatic SARS-CoV-2 infection. Myalgia/paraesthesia was indicative of somatosensory dysfunction. In all eight re-examined children, the nerve function recovered after 2–4 months. Interpretation This study provides evidence that in a subgroup of children and adolescents previously infected with SARS-CoV-2, regardless of their complaints, the function of large or small nerve fibres is presumably reversibly impaired.

Seroconversion rate and socio-economic and ethnic risk factors for SARS-CoV-2 infection in children in a population-based cohort, Germany, June 2020 to February 2021.

IntroductionSocio-economic and ethnic background have been discussed as possible risk factors for SARS-CoV-2 infections in children. Improved knowledge could lead to tailored prevention strategies and help improve infection control.AimWe aimed to identify risk factors for SARS-CoV-2 infections in children in the first and second wave of the pandemic.MethodsWe performed an observational population-based cohort study in children (6 months-18 years) scheduled for legally required preventive examination and their parents in a metropolitan region in Germany. Primary endpoint was the SARS-CoV-2 seroconversion rate during the study period. Risk factors assessed included age, pre-existing medical conditions, socio-economic factors and ethnicity.ResultsWe included 2,124 children and their parents. Seroconversion rates among children in all age groups increased 3-4-fold from June 2020 to February 2021. Only 24 of 58 (41%) seropositive children reported symptoms. In 51% of infected children, at least one parent was also SARS-CoV-2-positive. Low level of parental education (OR = 3.13; 95% CI: 0.72-13.69) non-significantly increased the risk of infection. Of the total cohort, 38.5% had a migration background, 9% of Turkish and 5% of Middle Eastern origin, and had the highest risk for SARS-CoV-2 infections (OR = 6.24; 95% CI: 1.38-28.12 and OR = 6.44 (95% CI: 1.14-36.45) after adjustment for other risk factors.ConclusionIn the second half of 2020, seroprevalence for SARS-CoV-2 in children increased especially in families with lower-socioeconomic status. Culture-sensitive approaches are essential to limit transmission and could serve as a blueprint for vaccination strategies.

Pulmonary Function and Long-Term Respiratory Symptoms in Children and Adolescents After COVID-19.

Background: Persistent respiratory symptoms after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in adults are frequent, and there can be long-term impairment of pulmonary function. To date, only preliminary evidence is available on persistent respiratory sequelae of SARS-CoV-2 in children and adolescents. Our objective was to examine the long-term effects of symptomatic and asymptomatic SARS-CoV-2 infections on pulmonary function in this age group in a single-center, controlled, prospective study. Methods: Participants with serological or polymerase chain reaction-based evidence of SARS-CoV-2 infection were recruited from a population-based study of seroconversion rates. Multiple-breath washout (MBW), body plethysmography, and diffusion capacity testing were performed for children and adolescents. Participants were interviewed about their symptoms during the acute phase of infection and long-lasting symptoms. Cases were compared with SARS-CoV-2 seronegative controls from the same population-based study with and without history of respiratory infection within 6 months prior to assessment. Primary endpoints were differences in pulmonary function, including diffusion capacity and MBW, between participants with and without evidence of SARS-CoV-2 infection. Secondary endpoints included correlation between lung function and long-lasting symptoms as well as disease severity. Findings: In total, 73 seropositive children and adolescents (5-18 years) were recruited after an average of 2.6 months (range 0.4-6.0) following SARS-CoV-2 infection. Among 19 patients (27.1%) who complained of persistent or newly emerged symptoms since SARS-CoV-2, 8 (11.4%) reported respiratory symptoms. No significant differences were detected in frequency of abnormal pulmonary function when comparing cases with 45 controls, including 14 (31.1%) with a history of previous infection (SARS-CoV-2: 12, 16.4%; controls: 12, 27.7%; odds ratio 0.54, 95% confidence interval 0.22-1.34). Only two patients with persistent respiratory symptoms showed abnormal pulmonary function. Multivariate analysis revealed reduced forced vital capacity (p = 0.012) in patients with severe SARS-CoV-2 infection. Interpretation: Pulmonary function is rarely impaired in children and adolescents after SARS-CoV-2 infection, except from those with severe infection, and did not differ between SARS-CoV-2 and other previous infections, suggesting that SARS-CoV-2 is not more likely to cause pulmonary sequelae than other infections. The discrepancy between persisting respiratory symptoms and normal pulmonary function suggests a different underlying pathology such as dysfunctional breathing.

To Mask or Not to Mask-Evaluation of Cognitive Performance in Children Wearing Face Masks during School Lessons (MasKids).

In the current SARS-CoV-2 pandemic, wearing a face mask is mandatory again during school lessons. There are no controlled studies in children to date indicating an effect on cognitive performance from wearing face masks. In a randomized controlled trial, we analysed the influence of face masks on cognitive performance of pupils during regular school lessons. Pupils (n = 133, fifth to seventh grade) were randomized by alternating allocation into control (with masks, n = 65) and intervention groups (without mask, n = 68). After two school lessons with (control) and without (intervention) face masks in class, all pupils performed digital tests for cognitive performance regarding attention and executive functions (switch, Corsi block-tapping, 2-back and flanker task). Overall, there were no significant differences in cognitive performance between both groups, masks vs. no masks. Wearing face masks has no significant influence on attention and executive functions of pupils and can still be recommended during school lessons.

Longitudinal Rise in Seroprevalence of SARS-CoV-2 Infections in Children in Western Germany-A Blind Spot in Epidemiology?

SARS-CoV-2 infection rates in children and adolescents are often underestimated due to asymptomatic or oligosymptomatic infections. Seroprevalence studies can reveal the magnitude of "silent" infections in this age group and help to assess the risk of infection for children but also their role in spreading the disease. In total, 2045 children and their parents from the Ruhr region were finally included after the exclusion of drop-outs. Seroconversion rates among children of all age groups increased from 0.5% to 8% during the study period and were about three to fourfold higher than the officially registered PCR-based infection rates. Only 41% recalled symptoms of infection; 59% were asymptomatic. In 51% of the infected children, at least one parent also developed SARS-CoV-2 antibodies. Depending on local incidences, the rates of seroconversion rose to different levels during the study period. Although the dynamics of infection within the study cohort mirrors local incidence, the figure of SARS-CoV-2 infections in children and adolescents appears to be high. Reported contact with SARS-CoV-2-infected individuals in the same household carries a high risk of infection.