SARS-CoV-2 continues to develop new, increasingly infectious variants including delta and omicron. We evaluated the efficacy of the Abbott BinaxNOW Rapid Antigen Test against Reverse Transcription ...PCR (RT-PCR) in 1,054 pediatric participants presenting to a high-volume Coronavirus Disease 2019 (COVID-19) testing site while the delta variant was predominant. Both tests utilized anterior nares swabs. Participants were grouped by COVID-19 exposure and symptom status. 5.2% of samples tested positive by RT-PCR for SARS-CoV-2. For all participants, sensitivity of the BinaxNOW was 92.7% (95% CI 82.4%-98.0%), and specificity was 98.0% (95% CI 97.0%-98.8%). For symptomatic participants, positive predictive value (PPV) was 72.7% (95% CI 54.5%-86.7%) and negative predictive value (NPV) was 99.2% (95% CI 98.2%-100%). Among asymptomatic participants, PPV was 71.4% (95% CI 53.7%-85.4%) and NPV was 99.7% (95% CI 99.0%-100%). Our reported sensitivity and NPV are higher than other pediatric studies, potentially because of higher viral load from the delta variant, but specificity and PPV are lower.
The BinaxNOW rapid antigen COVID-19 test had a sensitivity of nearly 92% in both symptomatic and asymptomatic children when performed at a high-throughput setting during the more transmissible delta variant dominant period. The test may play an invaluable role in asymptomatic screening and keeping children safe in school.
In November 2021, the World Health Organization declared the Omicron variant (B.1.1.519) a variant of concern. Since then, worries have been expressed regarding the ability of usual diagnostic tests ...to detect the Omicron variant. In addition, some recently published data suggested that the salivary reverse transcription (RT)-PCR might perform better than the current gold standard, nasopharyngeal (NP) RT-PCR. In this study, we aimed to compare the sensitivities of nasopharyngeal and saliva RT-PCR and assess the diagnostic performances of rapid antigen testing (RAT) in nasopharyngeal and saliva samples. We conducted a prospective clinical study among symptomatic health care professionals consulting the occupational health service of our hospital for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) screening and hospitalized patients in internal medicine/intensive care wards screened for SARS-CoV-2 with COVID-19-compatible symptoms. A composite outcome considering NP PCR and/or saliva PCR was used as a reference standard to define COVID-19 cases. A total of 475 paired NP/saliva specimens have been collected with a positivity rate of 40% (
= 192). NP and salivary RT-PCR exhibited sensitivities of 98% (95% CI, 94 to 99%) and 87% (95% CI, 81 to 91%), respectively, for outpatients (
= 453) and 94% (95% CI, 72 to 99%) and 69% (95% CI, 44 to 86%), respectively, for hospitalized patients (
= 22). Nasopharyngeal rapid antigen testing exhibited much lower diagnostic performances (sensitivity of 66% and 31% for outpatients and inpatients, respectively), while saliva RAT showed a sensitivity of less than 5% in both groups. Nasopharyngeal RT-PCR testing remains the gold standard for SARS-CoV-2 Omicron variant screening. Salivary RT-PCR can be used as an alternative in case of contraindication to perform NP sampling. The use of RAT should be limited to settings where access to molecular diagnostic methods is lacking.
The Omicron variant of concern spread rapidly since it was first reported in November 2021 and currently accounts for the vast majority of new infections worldwide. Recent reports suggest that saliva sampling might outweigh nasopharyngeal sampling for the diagnosis of the Omicron variant. Nevertheless, data investigating the best diagnostic strategy specifically for the Omicron variant of concern remain scarce. This study fills this gap in current knowledge and elucidates the question of which strategy to use in which patient. It provides a new basis for further improving COVID-19 screening programs and managing patients suspected to have COVID-19.
Rapid antigen tests are simple to perform and provide results within 15 min. We describe our implementation and assess performance of the BinaxNOW COVID-19 Antigen Test (Abbott Laboratories) in 6,099 ...adults at a self-referred walk-up testing site. Participants were grouped by self-reported COVID-19 exposure and symptom status. Most (89%) were asymptomatic, of whom 17% reported potential exposure. Overall test sensitivity compared with reference laboratory reverse-transcription RT PCR testing was 81% (95% confidence interval CI 75%, 86%). It was higher in symptomatic (87%; 95% CI 80%, 91%) than asymptomatic (71%; 95% CI 61%, 80%) individuals. Sensitivity was 82% (95% CI 66%, 91%) for asymptomatic individuals with potential exposure and 64% (95% CI 51%, 76%) for those with no exposure. Specificity was greater than 99% for all groups. BinaxNOW has high accuracy among symptomatic individuals and is below the FDA threshold for emergency use authorization in asymptomatic individuals. Nonetheless, rapid antigen testing quickly identifies positive among those with symptoms and/or close contact exposure and could expedite isolation and treatment.
The BinaxNOW rapid antigen COVID-19 test had a sensitivity of 87% in symptomatic and 71% asymptomatic individuals when performed by health care workers in a high-throughput setting. The performance may expedite isolation decisions or referrals for time-sensitive monoclonal antibody treatment in communities where timely COVID PCR tests are unavailable.
Scientific societies and conference secretariats have recently resumed in-person meetings after a long pause owing to the COVID-19 pandemic. Some safety measures continue to be implemented at these ...in-person events to limit the spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). With increased numbers of waves of infection, caused by the emergence of SARS-CoV-2 variants, additional information is needed to ensure maximal safety at in-person events. The MEX-DART case study was conducted at the in-person Hep-DART 2021 conference, which was held in Los Cabos, Mexico, in December 2021. Many COVID-19 safety measures were implemented, and incidence of SARS-CoV-2 infection during the conference was tested onsite. In this study, we highlight the specific conditions and safety measures set in place at the conference. In addition to vaccination requirements, social distancing, and mask wearing, daily rapid testing was implemented for the duration of the conference. At the end of the 4-day meeting, none of the 166 delegates (and family members attending the conference) had tested antigen positive for SARS-CoV-2. Two delegates tested positive in the week after the conference; the timing of their positive test result suggests that they contracted the virus during their travels home or during postconference vacationing. We believe that this model can serve as a helpful template for organizing future in-person meetings in the era of COVID-19 and any other respiratory virus pandemics of the future. While the outcomes of this case study are encouraging, seasonal surges in respiratory virus infections such as SARS-CoV-2, RSV, and influenza virus incidence suggest that continued caution is warranted.
Saliva sampling could serve as an alternative non-invasive sample for SARS-CoV-2 diagnosis while rapid antigen tests (RATs) might help to mitigate the shortage of reagents sporadically encountered ...with RT-PCR. Thus, in the RESTART study we compared antigen and RT-PCR testing methods on nasopharyngeal (NP) swabs and salivary samples. We conducted a prospective observational study among COVID-19 hospitalized patients between 10 December 2020 and 1 February 2021. Paired saliva and NP samples were investigated by RT-PCR (Cobas 6800, Roche-Switzerland, Basel, Switzerland) and by two rapid antigen tests: One Step Immunoassay Exdia
COVID-19 Ag (Precision Biosensor, Daejeon, Korea) and Standard Q
COVID-19 Rapid Antigen Test (Roche-Switzerland). A total of 58 paired NP-saliva specimens were collected. A total of 32 of 58 (55%) patients were hospitalized in the intensive care unit, and the median duration of symptoms was 11 days (IQR 5-19). NP and salivary RT-PCR exhibited sensitivity of 98% and 69% respectively, whereas the specificity of these RT-PCRs assays was 100%. The NP RATs exhibited much lower diagnostic performance, with sensitivities of 35% and 41% for the Standard Q
and Exdia
assays, respectively, when a wet-swab approach was used (i.e., when the swab was diluted in the viral transport medium (VTM) before testing). The sensitivity of the dry-swab approach was slightly better (47%). These antigen tests exhibited very low sensitivity (4% and 8%) when applied to salivary swabs. Nasopharyngeal RT-PCR is the most accurate test for COVID-19 diagnosis in hospitalized patients. RT-PCR on salivary samples may be used when nasopharyngeal swabs are contraindicated. RATs are not appropriate for hospitalized patients.
Central nervous system (CNS) infections are potentially life threatening if not diagnosed and treated early. The initial clinical presentations of many CNS infections are non-specific, making a ...definitive etiologic diagnosis challenging. Nucleic acid in vitro amplification-based molecular methods are increasingly being applied for routine microbial detection. These methods are a vast improvement over conventional techniques with the advantage of rapid turnaround and higher sensitivity and specificity. Additionally, molecular methods performed on cerebrospinal fluid samples are considered the new gold standard for diagnosis of CNS infection caused by pathogens, which are otherwise difficult to detect. Commercial diagnostic platforms offer various monoplex and multiplex PCR assays for convenient testing of targets that cause similar clinical illness. Pan-omic molecular platforms possess potential for use in this area. Although molecular methods are predicted to be widely used in diagnosing and monitoring CNS infections, results generated by these methods need to be carefully interpreted in combination with clinical findings. This review summarizes the currently available armamentarium of molecular assays for diagnosis of central nervous system infections, their application, and future approaches.
Purpose: Since the eye is in close proximity to the oro-nasal cavity, transmission of SARS CoV-2 is higher during ophthalmic surgical procedures, it is vital to ensure the safety of the healthcare ...team by pre-operative Rapid Antigen Test (RAT) and real-time Reverse Transcriptase Polymerase Chain Reaction (RT-PCR) for SARS CoV-2 viral RNA of all patients planned for elective or emergency surgery. Hence, understanding the profile of pre-operative RAT and real-time RT-PCR among patients planned for various ophthalmic procedures, will help us make better decisions for future guidelines, for optimal planning of ophthalmic elective or emergency surgeries, keeping in mind the current scenario. Methods: This is a prospective descriptive study conducted on patients planned for elective or emergency ophthalmic surgeries, who had no COVID-19-related symptoms pre-operatively and were subjected to preoperative RAT and real-time RT-PCR of nasopharyngeal and throat swabs for SARS CoV-2 viral RNA. Data was compiled and statistically analysed. Results: 204 patients underwent pre-operative RAT and RT-PCR testing; of which, 85 were females and 119 were males. Mean age of the study population was 51.44 ± 16.501 years. Among the 204, 2 tested positive for SARS CoV-2 with Rapid Antigen testing as well as RT-PCR and 10 patients tested positive via RT-PCR after a negative RAT result of the same sample. Conclusion: Pre-operative testing for COVID-19 disease is indispensable as there is a high chance of transmission from patient to healthcare workers. RAT has the advantage of quick results and may play a role in case of emergency procedures. However, it is prudent to perform the more sensitive real-time RT-PCR before any elective, non-emergency procedures or surgeries to avoid any undue risk to the healthcare team.
The majority of patients hospitalized with COVID-19 are older individuals. Age and the comorbidities typically associated with it usually go hand in hand with a less favorable course of the disease. ...We were interested in the antibody response in this particular patient group as well as in the results of rapid antigen testing.
In 30 elderly patients (>75 years), antibody titers (IgA and IgG) against COVID-19 were measured, and rapid antigen testing was determined about 3 weeks after the onset of symptoms of SARS-CoV-2 infection. The results were compared with those of a "high-risk" group consisting of "Covid-19" ward regular staff, as well as with "low-risk" staff consisting of members of the intensive care unit (ICU). The antibody titer against SARS-CoV-2 was determined by ELISA (EUROIMMUN™, PerkinElmer, Inc. Company); for rapid antigen testing, we used the SARS-CoV-2 Rapid Antigen test (Roche
).
Our investigations demonstrate a robust antibody response in the majority of elderly, comorbid patients about three weeks after the onset of infection. At this timepoint, most of the results of rapid antigen testing were negative. Furthermore, in the group of employees of our clinic ("Covid-19" ward vs. the ICU staff), the prevalence of antibodies was very low and antigen testing was negative in the whole ICU group.
Although frequently comorbid, elderly patients are capable of significantly increasing antibodies against COVID-19 about 3 weeks after the onset of infection. Since the viral load can be assumed to have been low at that point, rapid antigen testing was negative in most cases. In the test group of employees of our clinic ("Covid-19" ward vs. the ICU staff), the data demonstrate that - given adequate protective measures - the risk of infection is not higher in a "Covid-19" ward compared to other wards.
Abstract
Objective
The purpose of this study was to compare Quidel’s rapid antigen test Sofia SARS antigen Fluorescent Immunoassay (FIA) (Sofia) with the real-time reverse transcription–polymerase ...chain reaction (rRT-PCR) test.
Methods
Two samples were taken from each test subject—1 for testing with the Sofia test and 1 for testing with the rRT-PCR test. In total, swabs were taken from 146 subjects who presented symptoms of infection (group 1) and 672 subjects who were tested regardless of symptoms (group 2).
Results
In group 1, the sensitivity of the antigen test was 90.0% and its specificity 97.5%. In group 2, however, the sensitivity of the antigen test was 81.4% and the specificity 98.9%. In addition to asymptomatic patients, false-negative results of rapid antigen tests also occurred in subjects with high threshold values (cycle threshold > 30).
Conclusion
Our results show that the Sofia test meets the standards for diagnostic tests according to the criteria of the World Health Organization, as they show high sensitivity and specificity, and perhaps most importantly, a high negative predictive value (> 95%).
Abstract
Background
Mitigation of coronavirus disease 2019 (COVID-19) outbreaks in long-term care facilities (LTCFs) is facilitated by rapid identification and isolation of infectious individuals to ...interrupt viral transmission. Immunochromatographic (IC) tests, or rapid antigen tests, have high sensitivity and specificity during the contagious period for COVID-19. Mathematical modeling predicts frequent IC surveillance will be more efficient than polymerase chain reaction (PCR)-based strategies, especially during community surges when reporting of PCR results can be delayed. However, there are few published field studies evaluating IC testing strategies in this long-term care setting.
Methods
In fall and winter of 2020, the Marin Health and Human Services Department implemented thrice-weekly IC mass testing by nonlaboratory workers in outbreaks that occurred in 2 LTCFs, in addition to then-standard semiweekly PCR testing. The IC test performance was characterized using same-day PCR specimens as reference standard. Cumulative incidence and duration of transmission for the 2 IC intervention facility outbreaks were compared with 6 reference LTCFs that used weekly to semiweekly PCR alone during an outbreak response.
Results
Of 123 same-day test pairs, IC test sensitivity and specificity were 75% (95% confidence interval CI, 48%–93%) and 100% (95% CI, 97%–100%), respectively. The median duration of outbreak transmission was 19.5 days in the 2 intervention sites and 28 days in the reference facilities (P = .40). Cumulative incidence for the outbreaks among LTCF residents was 41% in the intervention facilities versus 52% in the reference facilities (P = .04, Fisher 2-sided exact).
Conclusions
Thrice-weekly mass IC testing as used by nonlaboratory personnel can be highly practical and effective for COVID-19 outbreak mitigation in the LTCF setting.
COVID-19 outbreaks in 2 long-term care facilities during fall and winter of 2020 were managed with thrice-weekly rapid antigen testing of staff and residents performed by nonlaboratory personnel, providing practical and effective mitigation superior to that of semiweekly PCR testing.
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