Positive Predictive Value of Rapid Antigen Tests in School During SARS-CoV-2 Omicron Variant Surge.
Ontology highlight
ABSTRACT:
SUBMITTER: Jang EJ
PROVIDER: S-EPMC9725737 | biostudies-literature | 2023 Jan
REPOSITORIES: biostudies-literature
Publications
Positive Predictive Value of Rapid Antigen Tests in School During SARS-CoV-2 Omicron Variant Surge.
Jang Eun Jung EJ Choe Young June YJ Yun Go-Woon GW Kim Ryu Kyung RK Jeong Heegwon H Lee Sangwon S Park Young-Joon YJ
The Pediatric infectious disease journal 20221018 1
In Korea, we conducted a national observational study to calculate the positive predictive value of SARS-CoV-2 rapid antigen tests in K-12 schools during the Omicron variant surge in March 2022. The weekly positive predictive value ranged from 86.4% to 93.2%. The positive predictive value was the highest among elementary school students with symptoms (95.7%) and lowest among teachers/staff without symptoms (70.9%). ...[more]
Similar Datasets
Project description:Rapid antigen detection (RAD) tests are commonly used for the diagnosis of SARS-CoV-2 infections. However, with the continuous emergence of new variants of concern (VOC), presenting various mutations potentially affecting the nucleocapsid protein, the analytical performances of these assays should be frequently reevaluated. One hundred and twenty samples were selected and tested with both RT-qPCR and six commercial RAD tests that are commonly sold in Belgian pharmacies. Of these, direct whole-genome sequencing identified the strains present in 116 samples, of which 70 were Delta and 46 were Omicron (BA.1 and BA.1.1 sub-lineages, respectively). The sensitivity across a wide range of Ct values (13.5 to 35.7; median = 21.3) ranged from 70.0% to 92.9% for Delta strains and from 69.6% to 78.3% for Omicron strains. When taking swabs with a low viral load (Ct > 25, corresponding to <4.9 log10 copies/mL), only the Roche RAD test showed acceptable performances for the Delta strains (80.0%), while poor performances were observed for the other RAD tests (20.0% to 40.0%). All the tested devices had poor performances for the Omicron samples with a low viral load (0.0% to 23.1%). The poor performances observed with low viral loads, particularly for the Omicron strain, is an important limitation of RAD tests, which is not sufficiently highlighted in the instructions for use of these devices.
| S-EPMC9031584 | biostudies-literature
Project description:ImportanceThe US Centers for Disease Control and Prevention shortened the recommended isolation period for SARS-CoV-2 infection from 10 days to 5 days in December 2021. It is unknown whether an individual with the infection may still have a positive result to a rapid antigen test and potentially be contagious at the end of this shortened isolation period.ObjectiveTo estimate the proportion of individuals with SARS-CoV-2 infection whose rapid antigen test is still positive starting 7 days postdiagnosis.Design, setting, and participantsThis case series analyzed student athletes at a National Collegiate Athletic Association Division I university campus who tested positive for SARS-CoV-2 between January 3 and May 6, 2022. Individuals underwent rapid antigen testing starting 7 days postdiagnosis to determine whether they could end their isolation period.ExposuresRapid antigen testing 7 days after testing positive for SARS-CoV-2.Main outcomes and measuresRapid antigen test results, symptom status, and SARS-CoV-2 variant identification via campus wastewater analysis.ResultsA total of 264 student athletes (140 [53%] female; mean [SD] age, 20.1 [1.2] years; range, 18-25 years) representing 268 infections (177 [66%] symptomatic, 91 [34%] asymptomatic) were included in the study. Of the 248 infections in individuals who did a day 7 test, 67 (27%; 95% CI, 21%-33%) tests were still positive. Patients with symptomatic infections were significantly more likely to test positive on day 7 vs those who were asymptomatic (35%; 95% CI, 28%-43% vs 11%; 95% CI, 5%-18%; P < .001). Patients with the BA.2 variant were also significantly more likely to test positive on day 7 compared with those with the BA.1 variant (40%; 95% CI, 29%-51% vs 21%; 95% CI, 15%-27%; P = .007).Conclusions and relevanceIn this case series, rapid antigen tests remained positive in 27% of the individuals after 7 days of isolation, suggesting that the Centers for Disease Control and Prevention-recommended 5-day isolation period may be insufficient in preventing ongoing spread of disease. Further studies are needed to determine whether these findings are present in a more heterogeneous population and in subsequent variants.
| S-EPMC9579911 | biostudies-literature
Project description:Responding to the fast-spreading SARS-CoV-2 Omicron variant, to improve screening efficiency, rapid antigen tests (RATs) were first added as a supplementary detection method in China in mid-March, 2022. What and how big a role RATs should play need to be supported by clinical data. Here, RAT performance and relevant factors in comparison with nucleic acid amplification tests (NAATs) were assessed in Omicron-infected inpatients. From the NAAT results, nasopharyngeal swabs (NPs) performed better than oropharyngeal swabs (OPs). RATs tested on NAAT positive NPs performed better than those with OP-positive samples. The RAT positivity rate was strongly associated with high levels of N and OFR1ab genes, especially in NPs where patients also had significantly longer hospital stays and shorter days from symptom onset to RAT testing. Self-performed RATs had a detection accuracy that was comparable to professionally performed RATs when the subjects were well guided. The antigen negative rate of the studied patients was 100% at discharge. These findings suggest that, in addition to a supplementary detection role, RATs can be an important strategy for evaluating the disease progression of Omicron-infected inpatients. This study provides important clinical data to support better rules regarding RATs under China's COVID-19 prevention and control policy.
| S-EPMC9422342 | biostudies-literature
Project description:Since autumn 2020, rapid antigen tests (RATs) have been implemented in several countries as an important pillar of the national testing strategy to rapidly screen for infections on site during the SARS-CoV-2 pandemic. The current surge in infection rates around the globe is driven by the variant of concern (VoC) omicron (B.1.1.529). Here, we evaluated the performance of nine SARS-CoV-2 RATs in a single-centre laboratory study. We examined a total of 115 SARS-CoV-2 PCR-negative and 166 SARS-CoV-2 PCR-positive respiratory swab samples (101 omicron, 65 delta (B.1.617.2)) collected from October 2021 until January 2022 as well as cell culture-expanded clinical isolates of both VoCs. In an assessment of the analytical sensitivity in clinical specimen, the 50% limit of detection (LoD50) ranged from 1.77 × 106 to 7.03 × 107 RNA copies subjected to the RAT for omicron compared to 1.32 × 105 to 2.05 × 106 for delta. To score positive in these point-of-care tests, up to 10-fold (LoD50) or 101-fold (LoD95) higher virus loads were required for omicron- compared to delta-containing samples. The rates of true positive test results for omicron samples in the highest virus load category (Ct values < 25) ranged between 31.4 and 77.8%, while they dropped to 0-8.3% for samples with intermediate Ct values (25-30). Of note, testing of expanded virus stocks suggested a comparable RAT sensitivity of both VoCs, questioning the predictive value of this type of in vitro-studies for clinical performance. Given their importance for national test strategies in the current omicron wave, awareness must be increased for the reduced detection rate of omicron infections by RATs and a short list of suitable RATs that fulfill the minimal requirements of performance should be rapidly disclosed.
| S-EPMC8858605 | biostudies-literature
Project description:Rapid Antigen Tests (RAT) have become an invaluable tool for combating the COVID-19 pandemic. However, concerns have been raised regarding the ability of existing RATs to effectively detect emerging SARS-CoV-2 variants. We compared the performance of eight commercially available, emergency use authorized RATs against the Delta and Omicron SARS-CoV-2 variants using individual patient and serially diluted pooled clinical samples. The RATs exhibited lower sensitivity for Omicron samples when using PCR Cycle threshold (C T ) value (a proxy for RNA concentration) as the comparator. Interestingly, however, they exhibited similar sensitivity for Omicron and Delta samples when using quantitative antigen concentration as the comparator. We further found that the Omicron samples had lower ratios of antigen to RNA, which offers a potential explanation for the apparent lower sensitivity of RATs for that variant when using C T value as a reference. Our findings underscore the complexity in assessing RAT performance against emerging variants and highlight the need for ongoing evaluation in the face of changing population immunity and virus evolution.
| S-EPMC9934810 | biostudies-literature
Project description:Rapid antigen tests (RATs) have become an invaluable tool for combating the COVID-19 pandemic. However, concerns have been raised regarding the ability of existing RATs to effectively detect emerging SARS-CoV-2 variants. We compared the performance of 10 commercially available, emergency use authorized RATs against the Delta and Omicron SARS-CoV-2 variants using both individual patient and serially diluted pooled clinical samples. The RATs exhibited lower sensitivity for Omicron samples when using PCR cycle threshold (CT) value (a rough proxy for RNA concentration) as the comparator. Interestingly, however, they exhibited similar sensitivity for Omicron and Delta samples when using quantitative antigen concentration as the comparator. We further found that the Omicron samples had lower ratios of antigen to RNA, which offers a potential explanation for the apparent lower sensitivity of RATs for that variant when using C T value as a reference. Our findings underscore the complexity in assessing RAT performance against emerging variants and highlight the need for ongoing evaluation in the face of changing population immunity and virus evolution.
| S-EPMC10654096 | biostudies-literature
Project description:We conducted a retrospective review of medical records of patients with croup seen during the coronavirus disease 2019 pandemic. Approximately 50% underwent testing for severe acute respiratory syndrome coronavirus 2. During the Delta wave, 2.8% of those tested were positive for severe acute respiratory syndrome coronavirus 2; this increased to 48.2% during the Omicron wave, demonstrating a strong correlation between the Omicron variant and croup.
| S-EPMC9085454 | biostudies-literature
Project description: Not available
| S-EPMC8612709 | biostudies-literature
Project description:BackgroundSARS-CoV-2 rapid antigen tests are an important public health tool.ObjectiveTo evaluate field performance of the BinaxNOW rapid antigen test (Abbott) compared with reverse transcriptase polymerase chain reaction (RT-PCR) for detecting infection with the Omicron variant of SARS-CoV-2.DesignCross-sectional surveillance study.SettingFree, walk-up, outdoor, urban community testing and vaccine site led by Unidos en Salud, serving a predominantly Latinx community highly impacted by COVID-19.ParticipantsPersons seeking COVID-19 testing in January 2022.MeasurementsSimultaneous BinaxNOW and RT-PCR from nasal, cheek, and throat swabs, including cycle threshold (Ct) measures; a lower Ct value is a surrogate for higher amounts of virus.ResultsAmong 731 persons tested with nasal swabs, there were 296 (40.5%) positive results on RT-PCR; 98.9% were the Omicron variant. BinaxNOW detected 95.2% (95% CI, 91% to 98%) of persons who tested positive on RT-PCR with a Ct value below 30, 82.1% (CI, 77% to 87%) of those who tested positive on RT-PCR with a Ct value below 35, and 65.2% (CI, 60% to 71%) of all who were positive on RT-PCR. Among 75 persons with simultaneous nasal and cheek swabs, BinaxNOW using a cheek swab failed to detect 91% (20 of 22) of specimens that were positive on BinaxNOW with a nasal swab. Among persons with simultaneous nasal and throat swabs who were positive on RT-PCR with a Ct value below 30, 42 of 49 (85.7%) were detected by nasal BinaxNOW, 23 of 49 (46.9%) by throat BinaxNOW, and 44 of 49 (89.8%) by either.LimitationParticipants were a cross-sectional sample from a community-based sentinel surveillance site, precluding study of viral or symptom dynamics.ConclusionBinaxNOW detected persons with high SARS-CoV-2 levels during the Omicron surge, enabling rapid responses to positive test results. Cheek or throat swabs should not replace nasal swabs. As currently recommended, high-risk persons with an initial negative BinaxNOW result should have repeated testing.Primary funding sourceUniversity of California, San Francisco.
| S-EPMC8943844 | biostudies-literature
Project description:BackgroundSince the beginning of the Sever Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) pandemic, school closure as a mitigating measure was at the center of a public and professional debate. While the negative effects of school closure cannot be ignored, accumulating data suggested that it is necessary for reducing community transmission. Our study presents an optional strategy for safe school opening during a pandemic, implemented in selected Israeli high schools by a special task force constructed by the Sheba Medical Center (SMC).MethodsThe study took place between November 2020 and April 2021. Three schools from different areas of Israel were enrolled. The participants were asked to undergo bi-weekly SARS-CoV-2 rapid diagnostic antigen tests (Ag-RDT). Those who tested positive were requested to self-isolate, whereas their school contacts were tested daily by Ag-RDT. Participants with a previously documented SARS-CoV-2 infection or who were found to be SARS-CoV-2 seropositive upon enrollment were exempted from screening.ResultsOf a total of 361 participants who enrolled in the study, 12.3% were found to be seropositive. Fourteen SARS-CoV-2 cases were detected (3.5%), 12 of them in one single school located in an endemic area for SARS-CoV-2. The 14 cases resulted in 84 days of COVID-19-related absence from school, comparing with 1775 potential days of COVID-19-related absence under a strategy implementing self-isolation instead of testing.ConclusionsSafe continuation of academic routine during the pandemic is possible when using rapid Ag-RDT as a screening tool, while allowing swab collection by trained students and teachers.
| S-EPMC9281426 | biostudies-literature