A longitudinal seroepidemiology study to evaluate antibody response to SARS-CoV-2 virus infection and vaccination in children in Calgary, Canada from July 2020 to April 2022: Alberta COVID-19 Childhood Cohort (AB3C) Study.

BACKGROUND: Measurement of SARS-CoV-2 antibody seropositivity is important to accurately understand exposure to infection and/or vaccination in specific populations. This study aimed to estimate the serologic response to SARS-CoV-2 virus infection and vaccination in children in Calgary, Alberta over a two-year period. METHODS: Children with or without prior SARS-CoV-2 infections, were enrolled in Calgary, Canada in 2020. Venous blood was sampled 4 times from July 2020 to April 2022 for SARS-CoV-2 nucleocapsid and spike antibodies. Demographic and clinical information was obtained including SARS-CoV-2 testing results and vaccination records. RESULTS: 1035 children were enrolled and 88.9% completed all 4 visits; median age 9 years (IQR: 5,13); 519 (50.1%) female; and 815 (78.7%) Caucasian. Before enrolment, 118 (11.4%) had confirmed or probable SARS-CoV-2. By April 2022, 39.5% of previously uninfected participants had a SARS-CoV-2 infection. Nucleocapsid antibody seropositivity declined to 16.4% of all infected children after more than 200 days post diagnosis. Spike antibodies remained elevated in 93.6% of unvaccinated infected children after more than 200 days post diagnosis. By April 2022, 408 (95.6%) children 12 years and older had received 2 or more vaccine doses, and 241 (61.6%) 5 to 11 year-old children had received 2 vaccine doses. At that time, all 685 vaccinated children had spike antibodies, compared with 94/176 (53.4%) of unvaccinated children. CONCLUSIONS: In our population, after the first peak of Omicron variant infections and introduction of COVID-19 vaccines for children, all vaccinated children, but just over one-half of unvaccinated children, had SARS-CoV-2 spike antibodies indicating infection and/or vaccination, highlighting the benefit of vaccination. It is not yet known whether a high proportion of seropositivity at the present time predicts sustained population-level protection against future SARS-CoV-2 transmission, infection or severe COVID-19 outcomes in children.

Insomnia in Adolescents with Slow Recovery from Concussion.

Sleep disruption can occur after brain injury; however, insomnia prevalence and severity in adolescents with persistent post-concussion symptoms have not been investigated. This study examined: 1) some of the psychometric properties of the Insomnia Severity Index (ISI), 2) the prevalence and severity of insomnia symptoms, and 3) associations between insomnia symptoms and clinical measures of post-concussion symptoms, mental health symptoms, and cognitive tests in adolescents with slow recovery from concussion. Participants (N = 121) were adolescents 13-18 years of age (mean = 16.2; standard deviation [SD] = 1.2) and, on average, of 6.4 months (SD = 3.8) post-concussion. This sample rated insomnia (ISI), post-concussion symptoms, symptoms of depression and anxiety, and cognitive complaints, as well as completed cognitive testing. The ISI demonstrated good internal consistency (alpha = 0.87) and a single factor structure. The majority of the sample endorsed at least some insomnia, with 62% being over the clinical cutoff for experiencing clinically significant symptoms of insomnia. Higher insomnia severity was associated with a greater number of previous concussions, worse post-concussion symptoms, more anxiety, and higher depression. Insomnia was significantly associated with more cognitive complaints and higher rates of failure on performance validity tests, but not with actual objectively measured cognitive abilities. Insomnia is common in adolescents with slow recovery from concussion and is associated with worse post-concussion symptoms, anxiety, depression, cognitive complaints, and performance validity concerns. Investigating evidence-based treatments for insomnia should be a priority in this population.