Ventilation during COVID-19 in a school for students with intellectual and developmental disabilities (IDD). (preprint)

Background: This study examined the correlation of classroom ventilation (air exchanges per hour (ACH)) and exposure to CO2 [≥]1,000 ppm with the incidence of SARS-CoV-2 over a 20-month period in a specialized school for students with intellectual and developmental disabilities (IDD). These students were at a higher risk of respiratory infection from SARS-CoV-2 due to challenges in tolerating mitigation measures (e.g. masking). One in-school measure that is suspected to help mitigate the risk of SARS-CoV-2 infection in schools is classroom ventilation. Methods: We established a community engaged research partnership between the University of Rochester and the Mary Cariola Center school for students with IDD. Ambient CO2 levels were measured in 100 rooms in the school, and air changes per hour (ACH) were calculated. The number of SARS-CoV-2 cases for each room was collected over 20 months. Results: 97% of rooms had an estimated ACH [≤]4.0, with 7% having CO2 levels [≥]1,000 PPM for up to 3 hours per school day. A statistically significant correlation was found between the time that a room had CO2 levels [≥]1,000 PPM and per-room SARS-CoV-2 PCR confirmed cases, accounting for 21% of the variance. No statistically significant correlation was found for room ACH and per-room SARS-CoV-2 cases. These findings led to ongoing efforts to upgrade the ventilation systems in this community engaged research project. Conclusions: There was a statistically significant correlation between the total time of room CO2 levels [≥]1,000 PPM during the school day and SARS-CoV-2 cases in that room in an IDD school. This research partnership identified areas for improving in-school ventilation.

A multiplex microsphere IgG assay for SARS-CoV-2 using ACE2-mediated inhibition as a surrogate for neutralization (preprint)

The COVID-19 pandemic has highlighted challenges inherent to serological detection of a novel pathogen like SARS-CoV-2. Serological tests can be used diagnostically and for surveillance, but their usefulness depends on throughput, sensitivity and specificity. Here, we describe a multiplex fluorescent microsphere-based assay, 3Flex, that can detect antibodies to three SARS-CoV-2 antigens-spike (S) protein, the spike ACE2 receptor-binding domain (RBD), and nucleocapsid (NP). Specificity was assessed using 213 pre-pandemic samples. Sensitivity was measured and compared to the Abbott ARCHITECT SARS-CoV-2 IgG assay using serum from 125 unique patients equally binned (n = 25) into 5 time intervals ([≤]5, 6 to 10, 11 to 15, 16 to 20, and [≥]21 days from symptom onset). With samples obtained at [≤]5 days from symptom onset, the 3Flex assay was more sensitive (48.0% vs. 32.0%), but the two assays performed comparably using serum obtained [≥]21 days from symptom onset. A larger collection (n = 534) of discarded sera was profiled from patients (n = 140) whose COVID-19 course was characterized through chart review. This revealed the relative rise, peak (S, 23.8; RBD, 23.6; NP, 16.7; in days from symptom onset), and decline of the antibody response. Considerable interperson variation was observed with a subset of extensively sampled ICU patients. Using soluble ACE2, inhibition of antibody binding was demonstrated for S and RBD, and not for NP. Taken together, this study described the performance of an assay built on a flexible and high-throughput serological platform that proved adaptable to the emergence of a novel infectious agent.