On January 26, 2021, this report was posted as an MMWR Early Release on the MMWR website (https://www.cdc.gov/mmwr). The coronavirus disease 2019 (COVID-19) pandemic has disrupted in-person learning in the United States, with approximately one half of all students receiving online-only instruction since March 2020.* Discontinuation of in-person schooling can result in many hardships (1) and disproportionately affects families of lower socioeconomic status (2). Current evidence suggests that transmission of SARS-CoV-2, the virus that causes COVID-19, in kindergarten through grade 12 (K-12) schools might not significantly contribute to COVID-19 spread nationwide (3). During August 31-November 29, 2020, COVID-19 cases, spread, and compliance with mask use were investigated among 4,876 students and 654 staff members who participated in in-person learning in 17 K-12 schools in rural Wisconsin. School-attributable COVID-19 case rates were compared with rates in the surrounding community. School administration and public health officials provided information on COVID-19 cases within schools. During the study period, widespread community transmission was observed, with 7%-40% of COVID-19 tests having positive results. Masking was required for all students and staff members at all schools, and rate of reported student mask-wearing was high (>92%). COVID-19 case rates among students and staff members were lower (191 cases among 5,530 persons, or 3,453 cases per 100,000) than were those in the county overall (5,466 per 100,000). Among the 191 cases identified in students and staff members, one in 20 cases among students was linked to in-school transmission; no infections among staff members were found to have been acquired at school. These findings suggest that, with proper mitigation strategies, K-12 schools might be capable of opening for in-person learning with minimal in-school transmission of SARS-CoV-2. Among 18 selected schools in Wood County, Wisconsin, 17 agreed to participate in this study of COVID-19 in schools and compliance with mask use. One school opted not to participate based on teacher preference. Surveillance was initiated by a small group of physician and medical student researchers. Participating schools were from three public school districts, one private school district, and one independent private school. Eight schools were elementary (grades K-6) with 1,529 students attending in-person, and nine were * Accessed January 13, 2021. https://cai.burbio.com/school-opening-tracker/

ABSTRACT.Purpose: To determine the prevalence of amblyopia in Denmark before and after the initiation of the Danish national preschool vision screening programme. Methods: In a population-based cross-sectional study, 3826 participants of the Danish General Suburban Population Study (GESUS) aged 20 years and older from a Danish rural municipality received a complete general health examination and an ophthalmological interview and examination. This study included a comprehensive ophthalmologic interview, measurement of best corrected visual acuity (BCVA) in each eye, Hirschberg's test for strabismus and two 45-degree retinal fundus photographs of each eye. A complete ophthalmologic examination was performed when indicated. Results: The prevalence of monocular visual impairment (MVI) was 4.26% (95% CI, 3.66-4.95, n = 163). Amblyopia was the most common cause, accounting for 33%. The prevalence of amblyopia was 1.44% (95% CI, 1.01-1.81, n = 55), being higher among non-preschool vision screened persons compared to those who were offered (estimated 95% attendance) preschool vision screening (1.78%, n = 41, 95% CI 1.24-2.33 versus 0.44%, n = 2, 95% CI, 0.12-1.60, p = 0.024). The leading cause of amblyopia was anisometropia (45.5%, 25/55). Conclusions: Amblyopia was the most common cause of MVI. Following the initiation of the Danish national preschool vision screening programme, which has an approximate attendance rate of 95%, the prevalence of amblyopia decreased by fourfold.

Background Male patients ages 12–17 years have an elevated risk of mRNA vaccination‐associated myo/pericarditis. A risk‐benefit analysis of first and second doses of mRNA vaccination in adolescent boys by health status and history of SARS‐CoV‐2 infection has not been performed. Methods Using the Vaccine Adverse Event Reporting System (VAERS), we identified BNT162b2 [Pfizer‐BioNTech] myo/pericarditis occurrence according to CDC criteria. Main outcomes were as follows: 1) post‐vaccination myo/pericarditis crude incidence in adolescents aged 12–15 and 16–17; and 2) two risk‐benefit analyses by age, sex, comorbidity, variant and history of infection. Results Cases of myo/pericarditis (n = 253) included 129 after dose 1 and 124 after dose 2; 86.9% were hospitalized. Incidence per million after dose two in male patients aged 12–15 and 16–17 was 162.2 and 93.0, respectively. Weighing post‐vaccination myo/pericarditis against COVID‐19 hospitalization during delta, our risk‐benefit analysis suggests that among 12–17‐year‐olds, two‐dose vaccination was uniformly favourable only in nonimmune girls with a comorbidity. In boys with prior infection and no comorbidities, even one dose carried more risk than benefit according to international estimates. In the setting of omicron, one dose may be protective in nonimmune children, but dose two does not appear to confer additional benefit at a population level. Conclusions Our findings strongly support individualized paediatric COVID‐19 vaccination strategies which weigh protection against severe disease vs. risks of vaccine‐associated myo/pericarditis. Research is needed into the nature and implications of this adverse effect as well as immunization strategies which reduce harms in this overall low‐risk cohort.

We report a relatively low frequency of VI among Danish adults over 59 years of age compared with that observed 10-15 years ago, which is both consistent with other recent Scandinavian studies and reflective of our relatively healthy and mobile population sample.