Point-of-care antigen tests are an important tool for SARS-CoV-2 detection. Antigen tests are less sensitive than real-time reverse transcriptase PCR (rRT-PCR).

BACKGROUND AND OBJECTIVES: Understanding the real-world impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mitigation measures, particularly vaccination, in children and adolescents in congregate settings remains important. We evaluated protection against SARS-CoV-2 infection using school-based testing data. METHODS: Using data from Utah middle- and high-school students participating in school-wide antigen testing in January 2022 during omicron (BA.1) variant predominance, log binomial models were fit to estimate the protection of previous SARS-CoV-2 infection and coronavirus disease 2019 vaccination against SARS-CoV-2 infection. RESULTS: Among 17 910 students, median age was 16 years (range: 12–19), 16.7% had documented previous SARS-CoV-2 infection; 55.6% received 2 vaccine doses with 211 median days since the second dose; and 8.6% of students aged 16 to 19 years received 3 vaccine doses with 21 median days since the third dose. Protection from previous infection alone was 35.9% (95% confidence interval [CI]: 12.9%–52.8%) and 23.8% (95% CI: 2.1%–40.7%) for students aged 12 to 15 and 16 to 19 years, respectively. Protection from 2-dose hybrid immunity (previous SARS-CoV-2 infection and vaccination) with <180 days since the second dose was 58.7% (95% CI: 33.2%–74.4%) for students aged 12 to 15 and 54.7% (95% CI: 31.0%–70.3%) for students aged 16 to 19 years. Protection was highest (70.0%, 95% CI: 42.3%–84.5%) among students with 3-dose hybrid immunity, although confidence intervals overlap with 2-dose vaccination. CONCLUSIONS: The estimated protection against infection was strongest for those with hybrid immunity from previous infection and recent vaccination with a third dose.

Background/Objectives: Respiratory viruses circulate year‐round and can spread indoors via inhalation of airborne particles. Effective ventilation and filtration may reduce transmission, particularly in school settings where children and staff spend significant time. This study examines the impact of indoor air quality (IAQ) and ventilation in schools on respiratory virus detection. Methods: During February 27 to March 30, 2023, we assessed the relationship between IAQ and respiratory viruses in two Kansas City, Missouri, elementary schools by collecting bioaerosol samples, student and staff nasal swabs, and monitoring IAQ across 10 rooms (six classrooms, two common spaces, and two nurses’ offices). We calculated air changes per hour (ACH) and analyzed viral detections in nasal swabs and bioaerosol samples by high (≥ 1000 ppm) or low (< 1000 ppm) CO ₂ concentration in classrooms. Results: We collected 173 nasal swabs from 100 participants and 30 bioaerosol samples from 10 rooms. Participants were mostly female (68%) and white (60%). Viruses were detected in 90% of bioaerosol and 35% of nasal samples. Four classrooms and both common spaces had the same virus detected in bioaerosol and nasal swab samples. None of the spaces met the CDC recommended ACH of 5, and only one exceeded ANSI/ASHRAE 62.1‐2022 standards for outdoor air supply. During school hours, 83% of classrooms had high average CO ₂ concentrations. Classrooms with high CO ₂ levels had higher viral detection. Conclusions: Viral presence was found in bioaerosol and nasal samples with some overlap in concurrently collected samples. Findings suggest a possible connection between high CO ₂ levels and virus detection. Improving IAQ and ventilation may reduce respiratory infection risks in schools. However, this study highlights the need to further assess the impact of various environmental modifications on respiratory virus transmission in schools, including determining optimal strategies such as ventilation, filtration, or germicidal ultraviolet energy.

Point-of-care antigen tests are an important tool for SARS-CoV-2 detection yet are less clinically sensitive than real-time reverse-transcription PCR (RT-PCR), impacting their efficacy as screening procedures. Our goal in this analysis was to see whether we could improve this sensitivity by considering antigen test results in combination with other relevant information, namely exposure status and reported symptoms. In November of 2020, we collected 3,419 paired upper respiratory specimens tested by RT-PCR and the Abbott BinaxNOW antigen test at two community testing sites in Pima County, Arizona. We used symptom, exposure, and antigen testing data to evaluate the sensitivity and specificity of various symptom definitions in predicting RT-PCR positivity. Our analysis yielded 6 novel multi-symptom case definitions with and without antigen test results, the best of which overall achieved a Youden’s J index of 0.66, as compared with 0.53 for antigen testing alone. Using a random forest as a guide, we show that this definition, along with our others, does not lose the ability to generalize well to new data despite achieving optimal performance in our sample. Our methodology is broadly applicable, and our code is publicly available to aid public health practitioners in developing or fine-tuning their own case definitions.