SARS-CoV-2 Infections and Incidence at a North Carolina Pre-Kindergarten-12 School During In-Person Education: August 2020 to January 2021

Secondary infections of COVID-19 in schools and the effectiveness of school-based interventions: a systematic review and meta-analysis

OBJECTIVES

This meta-analysis explored secondary infections of SARS-CoV-2 and the effectiveness of non-pharmaceutical interventions (NPIs) in school settings, with the aim of providing a reference to formulate scientific prevention and response strategies for similar major public health emergencies in specific settings.

STUDY DESIGN

This was a systematic review and meta-analysis.

METHODS

Systematic searches were conducted in PubMed, Web of Science and the Cochrane Library through to 1 August 2022 using the following key search terms: COVID-19, SARS-CoV-2, secondary attack rate, school, transmission, etc. The IVhet model was used for the meta-analysis, and the I2 index and Cochran's Q-test were used to assess heterogeneity. Publication bias was examined using Doi plot, Galbraith plots and Luis Furuya-Kanamori index. Prevalence Critical Appraisal Tool was used to assess the quality of the included articles, while Grading of Recommendations Assessment, Development, and Evaluation was used to rate the quality of the evidence. Subgroup analyses were conducted to explore the potential source of heterogeneity.

RESULTS

Thirty-four studies involving 226,727 school contacts and 2216 secondary cases were included in this study. The pooled secondary attack rates (SARs) of close contacts, staff contacts and student contacts were 0.67% (95% confidence interval [CI]: 0.11, 1.56), 0.79% (95% CI: 0.00, 6.72) and 0.50% (95% CI: 0.00, 4.48), respectively. Subgroup analysis suggested that multiple or specific combinations (e.g. the combination of contact restriction and hygiene action) of NPIs appeared to be associated with lower SARs.

CONCLUSIONS

The SAR of SARS-CoV-2 was low in schools. Multiple or specific combinations of prevention strategies appear to mitigate SARS-CoV-2 transmission in school settings. These findings provide a basis for continuous improvement of response strategies to major public health emergencies in the school environment.

School Absenteeism as a Marker for Community COVID-19 Rates

BACKGROUND

Reported community transmission rates of coronavirus disease 2019 (COVID-19) may not be accurate, particularly since at-home testing has become widely available. School absenteeism may serve as a marker of broader community COVID-19 transmission.

METHODS

We performed an observational study of North Carolina kindergarten through 12th grade schools participating in the ABC Science Collaborative that offered in-school instruction, and contributed severe acute respiratory syndrome coronavirus 2 data for at least 2 of 4 weeks monthly for the 2021-2022 academic year. Additionally, we analyzed publicly available databases including the North Carolina Department of Public Instruction, Centers for Disease Control and Prevention COVID-19 Data Repository, and National Center for Education Statistics. We described community and school COVID-19 infection rates compared with student monthly absenteeism rates to determine if the relationship between community COVID-19 infection rates and student absenteeism varied over time.

RESULTS

We included 500 192 students from 27 school districts. For the 2021-2022 academic year, the student and community COVID-19 infection rates did not show a significant difference (P > .05) across each month of comparison. Student absenteeism rates and community COVID-19 infection rates by month showed a similar trend across the academic year. For every 1% increase in community infection percentage, we found a 1.68% (1.12-2.25%) increase in absenteeism (P < .001); for every 1 month change in time, we found a 0.12% (0.01-0.24%) increase in absenteeism (P < .05).

CONCLUSIONS

Student absenteeism and infection rates may be a useful marker of COVID-19 community infection rates when testing frequency and results reporting are inconsistent.

Characterisation of infection-induced SARS-CoV-2 seroprevalence amongst children and adolescents in North Carolina

Few prospective studies have documented the seropositivity among those children infected with severe acute respiratory syndrome coronavirus 2. From 2 April 2021 to 24 June 2021, we prospectively enrolled children between the ages of 2 and 17 years at three North Carolina healthcare systems. Participants received at least four at-home serological tests detecting the presence of antibodies against, but not differentiating between, the nucleocapsid or spike antigen. A total of 1,058 participants were enrolled in the study, completing 2,709 tests between 1 May 2021 and 31 October 2021. Using multilevel regression with poststratification techniques and considering our assay sensitivity and sensitivity, we estimated that the seroprevalence of infection-induced antibodies among unvaccinated children and adolescents aged 2-17 years in North Carolina increased from 15.2% (95% credible interval, CrI 9.0-22.0) in May 2021 to 54.1% (95% CrI 46.7-61.1) by October 2021, indicating an average infection-to-reported-case ratio of 5. A rapid rise in seropositivity was most pronounced in those unvaccinated children aged 12-17 years, based on our estimates. This study underlines the utility of serial, serological testing to inform a broader understanding of the regional immune landscape and spread of infection.