Testing Frequency Matters: An Evaluation of the Diagnostic Performance of a Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Rapid Antigen Test in US Correctional Facilities

Abstract

Background The CDC recommends serial rapid antigen assay collection within congregate facilities. Though modeling and observational studies from communities and long-term care facilities have shown serial collection provides adequate sensitivity and specificity, the accuracy within correctional facilities remains unknown. Methods Using Connecticut Department of Corrections (DOC) data from November 21st 2020 to June 15th 2021, we estimated the accuracy of a rapid assay, BinaxNOW, under three collection strategies, single test collection and serial collection of two and three tests separated by 1-4 days. The sensitivity and specificity of the first (including single), second, and third serially collected BinaxNOW tests were estimated relative to RT-PCRs collected within one day of the BinaxNOW test. The accuracy metrics of the testing strategies were then estimated as the sum (sensitivity) and product (specificity) of tests in each strategy. Results Of the 13,112 residents who contributed ≥1 BinaxNOW test during the study period, 3,825 contributed ≥1 RT-PCR paired BinaxNOW test. In relation to RT-PCR, the three-rapid antigen test strategy had a sensitivity of 95.9% (95% confidence intervals (CI): 93.6-97.5%) and specificity of 98.3% (CI: 96.7-99.1%). The sensitivity of the two- and one-rapid antigen test strategies were 88.8% and 66.8%, respectively, and the specificities were 98.5% and 99.4%, respectively. The sensitivity was higher among symptomatic residents and when RT-PCRs were collected before BinaxNOW tests. Conclusions We found serial antigen test collection resulted in high diagnostic accuracy. These findings support serial collection for outbreak investigation, screening, and when rapid detection is required (such as intakes or transfers).

Evidence of Leaky Protection Following COVID-19 Vaccination and SARS-CoV-2 Infection in an Incarcerated Population

“…Our effect estimates on infectiousness during the Omicron period, while imprecise, are in alignment with a prior study by Tan et al 41 This study, conducted in California correctional facilities, found that the prior infection and vaccination status of an index case reduced the risk of transmission by 40% (20-55%) and 22% (6-36%), respectively. Similarly, we found that the risk of transmission following a cell exposure was 0.72 (0.25-2.03) times lower among infected residents with a prior infection and 0.52 (0.2-1.36) times lower among infected residents with a history of vaccination than residents without a prior infection or history of vaccination.…”

“…Similarly, we found that the risk of transmission following a cell exposure was 0.72 (0.25-2.03) times lower among infected residents with a prior infection and 0.52 (0.2-1.36) times lower among infected residents with a history of vaccination than residents without a prior infection or history of vaccination. Though our precision prevents us from making broad conclusions from these findings, they support the findings of Tan et al 41…”

“…Testing with rapid antigen test was and continues to be conducted for five primary reasons: intakes/transfers, symptomatic, employment, and contact tracing. 41,42 Among residents of cells, contact tracing is conducted among residents of the same cell as the infected residents and among residents of the same cellblock or facility but only if there was known contact with the infected resident. For each testing reason, a resident may have been provided a PCR or rapid antigen test.…”

The Impact of Repeating COVID-19 Rapid Antigen Tests on Prevalence Boundary Performance and Missed Diagnoses

“…In correctional facilities, Lind et al [30] showed that serial RAgTs had higher but diminishingly improved sensitivities over time, similar to the diminishing returns seen with repeat testing in the collaborative study. In a university setting, Smith et al [31] found that serial testing multiple times per week increased the sensitivity of RAgTs.…”

SARS-CoV-2 Virus Culture, Genomic and Subgenomic RNA Load, and Rapid Antigen Test in Experimentally Infected Syrian Hamsters

“…Some COVID-19 patients with low viral loads in the early disease stage may be missed by the RAgT assay. Through serial specimen collection, the three-rapid antigen test can increase the sensitivity of RAgT from 68.5% to an enough high level of 95.8% ( 13 ). The very high NPV suggests that individuals with negative RAgT results are temporarily not infectious, and whether the nucleic acid based-test is positive or negative, these recovered COVID-19 patients should be allowed to stop isolation immediately.…”