Respiratory Coinfections in Children With SARS-CoV-2.

BACKGROUND: As the transmission of endemic respiratory pathogens returns to prepandemic levels, understanding the epidemiology of respiratory coinfections in children with SARS-CoV-2 is of increasing importance. METHODS: We performed a retrospective analysis of all pediatric patients 0-21 years of age who had a multiplexed BioFire Respiratory Panel 2.1 test performed at Children's Healthcare of Atlanta, Georgia, from January 1 to December 31, 2021. We determined the proportion of patients with and without SARS-CoV-2 who had respiratory coinfections and performed Poisson regression to determine the likelihood of coinfection and its association with patient age. RESULTS: Of 19,199 respiratory panel tests performed, 1466 (7.64%) were positive for SARS-CoV-2, of which 348 (23.74%) also had coinfection with another pathogen. The most common coinfection was rhino/enterovirus (n = 230, 15.69%), followed by adenovirus (n = 62, 4.23%), and RSV (n = 45, 3.507%). Coinfections with SARS-CoV-2 were most commonly observed in the era of Delta (B.1.617.2) predominance (190, 54.60%), which coincided with periods of peak rhino/enterovirus and RSV transmission. Although coinfections were common among all respiratory pathogens, they were significantly less common with SARS-CoV-2 than other pathogens, with exception of influenza A and B. Children <2 years of age had the highest frequency of coinfection and of detection of any pathogen, including SARS-CoV-2. Among children with SARS-CoV-2, for every 1-year increase in age, the rate of coinfections decreased by 8% (95% CI, 6-9). CONCLUSIONS: Respiratory coinfections were common in children with SARS-CoV-2. Factors associated with the specific pathogen, host, and time period influenced the likelihood of coinfection.

Blood Coagulation and Beyond: Position Paper from the Fourth Maastricht Consensus Conference on Thrombosis.

The Fourth Maastricht Consensus Conference on Thrombosis included the following themes. Theme 1: The "coagulome" as a critical driver of cardiovascular disease. Blood coagulation proteins also play divergent roles in biology and pathophysiology, related to specific organs, including brain, heart, bone marrow, and kidney. Four investigators shared their views on these organ-specific topics. Theme 2: Novel mechanisms of thrombosis. Mechanisms linking factor XII to fibrin, including their structural and physical properties, contribute to thrombosis, which is also affected by variation in microbiome status. Virus infection-associated coagulopathies perturb the hemostatic balance resulting in thrombosis and/or bleeding. Theme 3: How to limit bleeding risks: insights from translational studies. This theme included state-of-the-art methodology for exploring the contribution of genetic determinants of a bleeding diathesis; determination of polymorphisms in genes that control the rate of metabolism by the liver of P2Y12 inhibitors, to improve safety of antithrombotic therapy. Novel reversal agents for direct oral anticoagulants are discussed. Theme 4: Hemostasis in extracorporeal systems: the value and limitations of ex vivo models. Perfusion flow chamber and nanotechnology developments are developed for studying bleeding and thrombosis tendencies. Vascularized organoids are utilized for disease modeling and drug development studies. Strategies for tackling extracorporeal membrane oxygenation-associated coagulopathy are discussed. Theme 5: Clinical dilemmas in thrombosis and antithrombotic management. Plenary presentations addressed controversial areas, i.e., thrombophilia testing, thrombosis risk assessment in hemophilia, novel antiplatelet strategies, and clinically tested factor XI(a) inhibitors, both possibly with reduced bleeding risk. Finally, COVID-19-associated coagulopathy is revisited.

Prevalence of SARS-CoV-2 in hemoglobinopathies is modified by age and race.

Prior literature has established a positive association between sickle cell disease and risk of contracting SARS-CoV-2. Data from a cross-sectional study evaluating COVID-19 testing devices (n = 10,567) was used to examine the association between underlying health conditions and SARS-CoV-2 infection in an urban metropolis in the southern United States. Firth's logistic regression was used to fit the model predicting SARS-CoV-2 positivity using vaccine status and different medical conditions commonly associated with COVID-19. Another model using the same method was built using SARS-CoV-2 positivity as the outcome and hemoglobinopathy presence, age (<16 Years vs. ≥16 Years), race/ethnicity and comorbidities, including hemoglobinopathy, as the factors. Our first model showed a significant association between hemoglobinopathy and SARS-CoV-2 infection (OR: 2.28, 95 % CI: (1.17,4.35), P = 0.016). However, in the second model, this association was not maintained (OR: 1.35, 95 % CI: (0.72,2.50), P = 0.344). We conclude that the association between SARS-CoV-2 positivity and presence of hemoglobinopathies like sickle cell disease is confounded by race, age, and comorbidity status. Our results illuminate previous findings by identifying underlying clinical/demographic factors that confound the reported association between hemoglobinopathies and SARS-CoV-2. These findings demonstrate how social determinants of health may influence disease manifestations more than genetics alone.

Investigation of Blood Plasma Viral Nucleocapsid Antigen as a Marker of Active Severe Acute Respiratory Syndrome Coronavirus 2 Omicron Variant Infection.

Background: Nasopharyngeal qualitative reverse-transcription polymerase chain reaction (RT-PCR) is the gold standard for diagnosis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, but it is not practical or sufficient in every clinical scenario due to its inability to distinguish active from resolved infection. Alternative or adjunct testing may be needed to guide isolation precautions and treatment in patients admitted to the hospital. Methods: We performed a single-center, retrospective analysis of residual clinical specimens and medical record data to examine blood plasma nucleocapsid antigen as a candidate biomarker of active SARS-CoV-2. Adult patients admitted to the hospital or presenting to the emergency department with SARS-CoV-2 ribonucleic acid (RNA) detected by RT-PCR from a nasopharyngeal swab specimen were included. Both nasopharyngeal swab and a paired whole blood sample were required to be available for analysis. Results: Fifty-four patients were included. Eight patients had positive nasopharyngeal swab virus cultures, 7 of whom (87.5%) had concurrent antigenemia. Nineteen (79.2%) of 24 patients with detectable subgenomic RNA and 20 (80.0%) of 25 patients with N2 RT-PCR cycle threshold ≤ 33 had antigenemia. Conclusions: Most individuals with active SARS-CoV-2 infection are likely to have concurrent antigenemia, but there may be some individuals with active infection in whom antigenemia is not detectable. The potential for high sensitivity and convenience of a blood test prompts interest in further investigation as a screening tool to reduce reliance on nasopharyngeal swab sampling and as an adjunct diagnostic test to aid in clinical decision making during the period after acute coronavirus disease 2019.

Pivot, persevere, or perish: how Ellume Health overcame development and regulatory obstacles to become the first authorized over-the-counter COVID-19 test in the United States.

The Ellume COVID-19 home test from Ellume Health (Brisbane, Aus) became the first COVID-19 diagnostic tool authorized for home use by the United States FDA in December 2020. This early pandemic success was built on over ten years of work on the Ellume influenza home test. Ellume overcame critical technology challenges during the development of their influenza test. In addition, it faced a recall of its COVID-19 home test in 2021 due to false positive results. While Ellume initially persevered through the recall and restarted sales in the United States, the combination of the recall and the wide availability of competitors' low-cost over the counter tests in the United States led to Ellume entering voluntary administration in September 2022. This paper traces the history of Ellume and how 10 years of experience with a home influenza test allowed the company to quickly develop the Ellume COVID-19 home test. We will also provide to diagnostic developers the key strategies employed by Ellume to succeed while highlighting the pitfalls that have challenged the company's business success.

SARS-CoV-2 molecular testing and whole genome sequencing following RNA recovery from used BinaxNOW COVID-19 antigen self tests.

Widespread use of over-the-counter rapid diagnostic tests for SARS-CoV-2 has led to a decrease in availability of clinical samples for viral genomic surveillance. As an alternative sample source, we evaluated RNA isolated from BinaxNOW swabs stored at ambient temperature for SARS-CoV-2 rRT-PCR and full viral genome sequencing. 81 of 103 samples (78.6%) yielded detectable RNA, and 46 of 57 samples (80.7 %) yielded complete genome sequences. Our results illustrate that SARS-CoV-2 RNA extracted from used Binax test swabs provides an important opportunity for improving SARS-CoV-2 genomic surveillance, evaluating transmission clusters, and monitoring within-patient evolution.

The critical role of engineering in the rapid development of COVID-19 diagnostics: Lessons from the RADx Tech Test Verification Core.

Engineering plays a critical role in the development of medical devices, and this has been magnified since 2020 as severe acute respiratory syndrome coronavirus 2 swept over the globe. In response to the coronavirus disease 2019, the National Institutes of Health launched the Rapid Acceleration of Diagnostics (RADx) initiative to help meet the testing needs of the United States and effectively manage the pandemic. As the Engineering and Human Factors team for the RADx Tech Test Verification Core, we directly assessed more than 30 technologies that ultimately contributed to an increase of the country's total testing capacity by 1.7 billion tests to date. In this review, we present central lessons learned from this "apples-to-apples" comparison of novel, rapidly developed diagnostic devices. Overall, the evaluation framework and lessons learned presented in this review may serve as a blueprint for engineers developing point-of-care diagnostics, leaving us better prepared to respond to the next global public health crisis rapidly and effectively.

SARS-CoV-2 molecular testing and whole genome sequencing following RNA recovery from used BinaxNOW COVID-19 Antigen Self Tests

Widespread use of over-the-counter rapid diagnostic tests for SARS-CoV-2 has led to a decrease in availability of clinical samples for viral genomic surveillance. As an alternative sample source, we evaluated RNA isolated from BinaxNOW swabs stored at ambient temperature for SARS-CoV-2 rRT-PCR and full viral genome sequencing. 81 of 103 samples (78.6%) yielded detectable RNA, and 46 of 57 samples (80.7 %) yielded complete genome sequences. Our results illustrate that SARS-CoV-2 RNA extracted from used Binax test swabs provides an important opportunity for improving SARS-CoV-2 genomic surveillance, evaluating transmission clusters, and monitoring within-patient evolution.

Lessons Learned from In-Person Conferences in the Times of COVID-19.

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.

Multiplatform analyses reveal distinct drivers of systemic pathogenesis in adult versus pediatric severe acute COVID-19.

The pathogenesis of multi-organ dysfunction associated with severe acute SARS-CoV-2 infection remains poorly understood. Endothelial damage and microvascular thrombosis have been identified as drivers of COVID-19 severity, yet the mechanisms underlying these processes remain elusive. Here we show alterations in fluid shear stress-responsive pathways in critically ill COVID-19 adults as compared to non-COVID critically ill adults using a multiomics approach. Mechanistic in-vitro studies, using microvasculature-on-chip devices, reveal that plasma from critically ill COVID-19 adults induces fibrinogen-dependent red blood cell aggregation that mechanically damages the microvascular glycocalyx. This mechanism appears unique to COVID-19, as plasma from non-COVID sepsis patients demonstrates greater red blood cell membrane stiffness but induces less significant alterations in overall blood rheology. Multiomics analyses in pediatric patients with acute COVID-19 or the post-infectious multi-inflammatory syndrome in children (MIS-C) demonstrate little overlap in plasma cytokine and metabolite changes compared to adult COVID-19 patients. Instead, pediatric acute COVID-19 and MIS-C patients show alterations strongly associated with cytokine upregulation. These findings link high fibrinogen and red blood cell aggregation with endotheliopathy in adult COVID-19 patients and highlight differences in the key mediators of pathogenesis between adult and pediatric populations.

Severe acute respiratory syndrome coronavirus 2 vaccine breakthrough infections: A single metro-based testing network experience.

Objectives: Understanding the incidence and characteristics that influence severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine breakthrough infections (VBIs) is imperative for developing public health policies to mitigate the coronavirus disease of 2019 (COVID-19) pandemic. We examined these factors and post-vaccination mitigation practices in individuals partially and fully vaccinated against SARS-CoV-2. Materials and methods: Adults >18 years old were voluntarily enrolled from a single metro-based SARS-CoV-2 testing network from January to July 2021. Participants were categorized as asymptomatic or symptomatic, and as unvaccinated, partially vaccinated, or fully vaccinated. All participants had confirmed SARS-CoV-2 infection based on standard of care (SOC) testing with nasopharyngeal swabs. Variant analysis by rRT-PCR was performed in a subset of time-matched vaccinated and unvaccinated individuals. A subgroup of partially and fully vaccinated individuals with a positive SARS-CoV-2 rRT-PCR was contacted to assess disease severity and post-vaccination mitigation practices. Results: Participants (n = 1,317) voluntarily underwent testing for SARS-CoV-2 during the enrollment period. A total of 29.5% of the population received at least one SARS-CoV-2 vaccine (n = 389), 12.8% partially vaccinated (n = 169); 16.1% fully vaccinated (n = 213). A total of 21.3% of partially vaccinated individuals tested positive (n = 36) and 9.4% of fully vaccinated individuals tested positive (n = 20) for SARS-CoV-2. Pfizer/BioNTech mRNA-1273 was the predominant vaccine received (1st dose = 66.8%, 2nd dose = 67.9%). Chronic liver disease and immunosuppression were more prevalent in the vaccinated (partially/fully) group compared to the unvaccinated group (p = 0.003, p = 0.021, respectively). There were more asymptomatic individuals in the vaccinated group compared to the unvaccinated group [n = 6 (10.7%), n = 16 (4.1%), p = 0.045]. CT values were lower for the unvaccinated group (median 24.3, IQR 19.1-30.5) compared to the vaccinated group (29.4, 22.0-33.7, p = 0.004). In the vaccinated group (n = 56), 18 participants were successfully contacted, 7 were lost to follow-up, and 2 were deceased. A total of 50% (n = 9) required hospitalization due to COVID-19 illness. Adherence to nationally endorsed mitigation strategies varied post-vaccination. Conclusion: The incidence of SARS-CoV-2 infection at this center was 21.3% in the partially vaccinated group and 9.4% in the fully vaccinated group. Chronic liver disease and immunosuppression were more prevalent in the vaccinated SARS-CoV-2 positive group, suggesting that these may be risk factors for VBIs. Partially and fully vaccinated individuals had a higher incidence of asymptomatic SARS-CoV-2 and higher CT values compared to unvaccinated SARS-CoV-2 positive individuals.

Hyperviscosity syndromes; hemorheology for physicians and the use of microfluidic devices.

PURPOSE OF REVIEW: Hyperviscosity syndromes can lead to significant morbidity and mortality. Existing methods to measure microcirculatory rheology are not readily available and limited in relevance and accuracy at this level. In this review, we review selected hyperviscosity syndromes and the advancement of their knowledge using microfluidic platforms. RECENT FINDINGS: Viscosity changes drastically at the microvascular level as the physical properties of the cells themselves become the major determinants of resistance to blood flow. Current, outdated viscosity measurements only quantify whole blood or serum. Changes in blood composition, cell number, or the physical properties themselves lead to increased blood viscosity. Given the significant morbidity and mortality from hyperviscosity syndromes, new biophysical tools are needed and being developed to study microvascular biophysical and hemodynamic conditions at this microvascular level to help predict those at risk and guide therapeutic treatment. SUMMARY: The use of 'lab-on-a-chip' technology continues to rise to relevance with point of care, personalized testing and medicine as customizable microfluidic platforms enable independent control of many in vivo factors and are a powerful tool to study microcirculatory hemorheology.

Subgenomic RNA Abundance Relative to Total Viral RNA Among Severe Acute Respiratory Syndrome Coronavirus 2 Variants.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) subgenomic RNA (sgRNA) may indicate actively replicating virus, but sgRNA abundance has not been systematically compared between SARS-CoV-2 variants. sgRNA was quantified in 169 clinical samples by real-time reverse-transcription polymerase chain reaction, demonstrating similar relative abundance among known variants. Thus, sgRNA detection can identify individuals with active viral replication regardless of variant.

SARS-CoV-2 Antigenemia is Associated With Pneumonia in Children But Lacks Sensitivity to Diagnose Acute Infection.

BACKGROUND: Nucleocapsid antigenemia in adults has demonstrated high sensitivity and specificity for acute infection, and antigen burden is associated with disease severity. Data regarding SARS-CoV-2 antigenemia in children are limited. METHODS: We retrospectively analyzed blood plasma specimens from hospitalized children with COVID-19 or MIS-C. Nucleocapsid and spike were measured using ultrasensitive immunoassays. RESULTS: We detected nucleocapsid antigenemia in 62% (50/81) and spike antigenemia in 27% (21/79) of children with acute COVID-19 but 0% (0/26) and 15% (4/26) with MIS-C from March 2020-March 2021. Higher nucleocapsid levels were associated with radiographic infiltrates and respiratory symptoms in children with COVID-19. CONCLUSIONS: Antigenemia lacks the sensitivity to diagnose acute infection in children but is associated with signs and symptoms of lower respiratory tract involvement. Further study into the mechanism of antigenemia, its association with specific organ involvement, and the role of antigenemia in the pathogenesis of COVID-19 is warranted.

Severe acute respiratory syndrome coronavirus 2 vaccine breakthrough infections: A single metro-based testing network experience

Objectives Understanding the incidence and characteristics that influence severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine breakthrough infections (VBIs) is imperative for developing public health policies to mitigate the coronavirus disease of 2019 (COVID-19) pandemic. We examined these factors and post-vaccination mitigation practices in individuals partially and fully vaccinated against SARS-CoV-2. Materials and methods Adults >18 years old were voluntarily enrolled from a single metro-based SARS-CoV-2 testing network from January to July 2021. Participants were categorized as asymptomatic or symptomatic, and as unvaccinated, partially vaccinated, or fully vaccinated. All participants had confirmed SARS-CoV-2 infection based on standard of care (SOC) testing with nasopharyngeal swabs. Variant analysis by rRT-PCR was performed in a subset of time-matched vaccinated and unvaccinated individuals. A subgroup of partially and fully vaccinated individuals with a positive SARS-CoV-2 rRT-PCR was contacted to assess disease severity and post-vaccination mitigation practices. Results Participants (n = 1,317) voluntarily underwent testing for SARS-CoV-2 during the enrollment period. A total of 29.5% of the population received at least one SARS-CoV-2 vaccine (n = 389), 12.8% partially vaccinated (n = 169);16.1% fully vaccinated (n = 213). A total of 21.3% of partially vaccinated individuals tested positive (n = 36) and 9.4% of fully vaccinated individuals tested positive (n = 20) for SARS-CoV-2. Pfizer/BioNTech mRNA-1273 was the predominant vaccine received (1st dose = 66.8%, 2nd dose = 67.9%). Chronic liver disease and immunosuppression were more prevalent in the vaccinated (partially/fully) group compared to the unvaccinated group (p = 0.003, p = 0.021, respectively). There were more asymptomatic individuals in the vaccinated group compared to the unvaccinated group [n = 6 (10.7%), n = 16 (4.1%), p = 0.045]. CT values were lower for the unvaccinated group (median 24.3, IQR 19.1–30.5) compared to the vaccinated group (29.4, 22.0–33.7, p = 0.004). In the vaccinated group (n = 56), 18 participants were successfully contacted, 7 were lost to follow-up, and 2 were deceased. A total of 50% (n = 9) required hospitalization due to COVID-19 illness. Adherence to nationally endorsed mitigation strategies varied post-vaccination. Conclusion The incidence of SARS-CoV-2 infection at this center was 21.3% in the partially vaccinated group and 9.4% in the fully vaccinated group. Chronic liver disease and immunosuppression were more prevalent in the vaccinated SARS-CoV-2 positive group, suggesting that these may be risk factors for VBIs. Partially and fully vaccinated individuals had a higher incidence of asymptomatic SARS-CoV-2 and higher CT values compared to unvaccinated SARS-CoV-2 positive individuals.

Comparison of Mid-turbinate Nasal Swabs, Saliva, and Nasopharyngeal Swabs for SARS-CoV-2 Reverse Transcription-Polymerase Chain Reaction Testing in Pediatric Outpatients.

CONTEXT.­: Diagnostic testing for SARS-CoV-2 in symptomatic and asymptomatic children remains integral to care, particularly for supporting return to and attendance in schools. The concordance of SARS-CoV-2 detection in children, using various specimen types, has not been widely studied. OBJECTIVE.­: To compare 3 sample types for SARS-CoV-2 polymerase chain reaction (PCR) testing in children, collected and tested at a single facility. DESIGN.­: We prospectively recruited 142 symptomatic and asymptomatic children/young adults into a sample comparison study performed in a single health care system. Each child provided self-collected saliva, and a trained health care provider collected a mid-turbinate nasal swab and nasopharyngeal (NP) swab. Specimens were assayed within 24 hours of collection by using reverse transcription-polymerase chain reaction (RT-PCR) to detect SARS-CoV-2 on a single testing platform. RESULTS.­: Concurrently collected saliva and mid-turbinate swabs had greater than 95% positive agreement with NP swabs when obtained within 10 days of symptom onset. Positive agreement of saliva and mid-turbinate samples collected from children with symptom onset >10 days prior, or without symptoms, was 82% compared to NP swab samples. Cycle threshold (Ct) values for mid-turbinate nasal samples more closely correlated with Ct values from NP samples than from saliva samples. CONCLUSIONS.­: These findings suggest that all 3 sample types from children are useful for SARS-CoV-2 diagnostic testing by RT-PCR, and that concordance is greatest when the child has had symptoms of COVID-19 within the past 10 days. This study provides scientific justification for using sample types other than the NP swab for SARS-CoV-2 testing in pediatric populations.

Clinical evaluation of the Diagnostic Analyzer for Selective Hybridization (DASH): A point-of-care PCR test for rapid detection of SARS-CoV-2 infection.

BACKGROUND: An ideal test for COVID-19 would combine the sensitivity of laboratory-based PCR with the speed and ease of use of point-of-care (POC) or home-based rapid antigen testing. We evaluated clinical performance of the Diagnostic Analyzer for Selective Hybridization (DASH) SARS-CoV-2 POC rapid PCR test. METHODS: We conducted a cross-sectional study of adults with and without symptoms of COVID-19 at four clinical sites where we collected two bilateral anterior nasal swabs and information on COVID-19 symptoms, vaccination, and exposure. One swab was tested with the DASH SARS-CoV-2 POC PCR and the second in a central laboratory using Cepheid Xpert Xpress SARS-CoV-2 PCR. We assessed test concordance and calculated sensitivity, specificity, negative and positive predictive values using Xpert as the "gold standard". RESULTS: We enrolled 315 and analyzed 313 participants with median age 42 years; 65% were female, 62% symptomatic, 75% had received ≥2 doses of mRNA COVID-19 vaccine, and 16% currently SARS-CoV-2 positive. There were concordant results for 307 tests indicating an overall agreement for DASH of 0.98 [95% CI 0.96, 0.99] compared to Xpert. DASH performed at 0.96 [95% CI 0.86, 1.00] sensitivity and 0.98 [95% CI 0.96, 1.00] specificity, with a positive predictive value of 0.85 [95% CI 0.73, 0.96] and negative predictive value of 0.996 [95% CI 0.99, 1.00]. The six discordant tests between DASH and Xpert all had high Ct values (>30) on the respective positive assay. DASH and Xpert Ct values were highly correlated (R = 0.89 [95% CI 0.81, 0.94]). CONCLUSIONS: DASH POC SARS-CoV-2 PCR was accurate, easy to use, and provided fast results (approximately 15 minutes) in real-life clinical settings with an overall performance similar to an EUA-approved laboratory-based PCR.

Nucleocapsid Antigenemia in Patients Receiving Anti-CD20 Therapy With Protracted COVID-19.

Immunocompromised patients with prolonged coronavirus disease 2019 symptoms present diagnostic and therapeutic challenges. We measured viral nucleocapsid antigenemia in 3 patients treated with anti-CD20 immunotherapy who acquired severe acute respiratory syndrome coronavirus 2 infection and experienced protracted symptoms. Our results support nucleocapsid antigenemia as a marker of persistent infection and therapeutic response.

Deep mutational scanning identifies SARS-CoV-2 Nucleocapsid escape mutations of currently available rapid antigen tests.

The effects of mutations in continuously emerging variants of SARS-CoV-2 are a major concern for the performance of rapid antigen tests. To evaluate the impact of mutations on 17 antibodies used in 11 commercially available antigen tests with emergency use authorization, we measured antibody binding for all possible Nucleocapsid point mutations using a mammalian surface-display platform and deep mutational scanning. The results provide a complete map of the antibodies' epitopes and their susceptibility to mutational escape. Our data predict no vulnerabilities for detection of mutations found in variants of concern. We confirm this using the commercial tests and sequence-confirmed COVID-19 patient samples. The antibody escape mutational profiles generated here serve as a valuable resource for predicting the performance of rapid antigen tests against past, current, as well as any possible future variants of SARS-CoV-2, establishing the direct clinical and public health utility of our system.