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1.
J Clin Virol ; 145: 105024, 2021 12.
Article in English | MEDLINE | ID: covidwho-1768294

ABSTRACT

BACKGROUND: After receiving a COVID-19 vaccine, most recipients want to know if they are protected from infection and for how long. Since neutralizing antibodies are a correlate of protection, we developed a lateral flow assay (LFA) that measures levels of neutralizing antibodies from a drop of blood. The LFA is based on the principle that neutralizing antibodies block binding of the receptor-binding domain (RBD) to angiotensin-converting enzyme 2 (ACE2). METHODS: The ability of the LFA was assessed to correctly measure neutralization of sera, plasma or whole blood from patients with COVID-19 using SARS-CoV-2 microneutralization assays. We also determined if the LFA distinguished patients with seasonal respiratory viruses from patients with COVID-19. To demonstrate the usefulness of the LFA, we tested previously infected and non-infected COVID-19 vaccine recipients at baseline and after first and second vaccine doses. RESULTS: The LFA compared favorably with SARS-CoV-2 microneutralization assays with an area under the ROC curve of 98%. Sera obtained from patients with seasonal coronaviruses did not show neutralizing activity in the LFA. After a single mRNA vaccine dose, 87% of previously infected individuals demonstrated high levels of neutralizing antibodies. However, if individuals were not previously infected, only 24% demonstrated high levels of neutralizing antibodies after one vaccine dose. A second dose boosted neutralizing antibody levels just 8% higher in previously infected individuals, but over 63% higher in non-infected individuals. CONCLUSIONS: A rapid, semi-quantitative, highly portable and inexpensive neutralizing antibody test might be useful for monitoring rise and fall in vaccine-induced neutralizing antibodies to COVID-19.


Subject(s)
COVID-19 , SARS-CoV-2 , Antibodies, Neutralizing , Antibodies, Viral , COVID-19 Vaccines , Humans , Point-of-Care Testing , Spike Glycoprotein, Coronavirus , Vaccines, Synthetic
2.
2021.
Preprint in English | Other preprints | ID: ppcovidwho-294853

ABSTRACT

Background The COVID-19 pandemic has accelerated the pace of innovation around virtual care visits and testing technology. Here we present the SafeSwab (Safe Health Systems, Los Angeles, CA), an integrated, universal sample collection and dispensing device that is designed to minimize user error and enable rapid testing in a point of care or self-testing format. Methods The SafeSwab was used with the Safe Health Systems HealthCheck digital health application to enable self-testing by patients using lateral flow tests for SARS-CoV-2 antigen or for antibodies against SARS-CoV-2. Results Patients (n=74) using the SafeSwab produced a valid rapid test result in 96% of attempts, and 96% of patients felt confident that they had collected a good sample. The Safe HealthCheck app has an integrated image analysis algorithm, AutoAdapt LFA, that interprets a picture of a rapid test result, and the algorithm interpreted the result correctly 100% of the time. Conclusion The SafeSwab was found to be versatile and easy to use for both self-collected nasal sampling as well as fingerstick blood sampling. The use of Safe Health Systems HealthCheck app allows an integrated solution for patient instruction and test interpretation

3.
2021.
Preprint in English | Other preprints | ID: ppcovidwho-294138

ABSTRACT

Point-of-care lateral-flow assays (LFAs) are becomingly increasingly prevalent for diagnosing individual patient disease status and surveying population disease prevalence in a timely, scalable, and cost-effective manner, but a central challenge is to assure correct assay operation and results interpretation as the assays are manually performed in decentralized settings. A smartphone-based software can automate interpretation of an LFA kit, but such algorithms typically require a very large number of images of assays tested with validated specimens, which is challenging to collect for different assay kits, especially for those released during a pandemic. Here, we present an approach – AutoAdapt LFA – that uses few-shot learning, an approach used in other applications such as computer vision and robotics, for accurate and automated interpretation of LFA kits that requires a small number of validated images for training. The approach consists of three components: extraction of membrane and zone areas from an image of the LFA kit, a self-supervised encoder that employs a feature extractor trained with edge-filtered patterns, and few-shot adaptation that enables generalization to new kits using limited validated images. From a base model pre-trained on a commercial LFA kit, we demonstrated the ability of adapted models to interpret results from five new COVID-19 LFA kits (three detecting antigens for diagnosing active infection, and two detecting antibodies for diagnosing past infection). Specifically, using just 10 to 20 images of each new kit, we achieved accuracies of 99% to 100% for each kit. The server-hosted algorithm has an execution time of approximately 4 seconds, which can potentially enable quality assurance and linkage to care for users operating new LFAs in decentralized settings.

4.
J Proteome Res ; 20(7): 3404-3413, 2021 07 02.
Article in English | MEDLINE | ID: covidwho-1253877

ABSTRACT

SARS-CoV-2 infection has become a major public health burden and affects many organs including lungs, kidneys, the liver, and the brain. Although the virus is readily detected and diagnosed using nasopharyngeal swabs by reverse transcriptase polymerase chain reaction (RT-PCR), detection of its presence in body fluids is fraught with difficulties. A number of published studies have failed to detect viral RNA by RT-PCR methods in urine. Although microbial identification in clinical microbiology using mass spectrometry is undertaken after culture, here we undertook a mass spectrometry-based approach that employed an enrichment step to capture and detect SARS-CoV-2 nucleocapsid protein directly from urine of COVID-19 patients without any culture. We detected SARS-CoV-2 nucleocapsid protein-derived peptides from 13 out of 39 urine samples. Further, a subset of COVID-19 positive and COVID-19 negative urine samples validated by mass spectrometry were used for the quantitative proteomics analysis. Proteins with increased abundance in urine of SARS-CoV-2 positive individuals were enriched in the acute phase response, regulation of complement system, and immune response. Notably, a number of renal proteins such as podocin (NPHS2), an amino acid transporter (SLC36A2), and sodium/glucose cotransporter 5 (SLC5A10), which are intimately involved in normal kidney function, were decreased in the urine of COVID-19 patients. Overall, the detection of viral antigens in urine using mass spectrometry and alterations of the urinary proteome could provide insights into understanding the pathogenesis of COVID-19.


Subject(s)
Body Fluids , COVID-19 , Antigens, Viral , Humans , Immunity , Mass Spectrometry , Phosphoproteins , RNA, Viral , SARS-CoV-2
5.
Diagn Microbiol Infect Dis ; 98(3): 115161, 2020 Nov.
Article in English | MEDLINE | ID: covidwho-776481

ABSTRACT

In a Clinical Laboratory Improvement Amendments laboratory setting, we evaluated severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) IgG detection with 4 lateral flow immunoassays [LFIAs; 2 iterations from BTNX Inc. (n = 457) and 1 each from ACON Laboratories (n = 200) and SD BIOSENSOR (n = 155)]. In a cohort of primarily hospitalized, reverse-transcription polymerase chain reaction-confirmed coronavirus disease 2019 cases, sensitivity at ≥14 days from symptom onset was: BTNX kit 1, 95%; BTNX kit 2, 91%; ACON, 95%; and SD, 92%. All assays showed good concordance with the Abbott SARS-CoV-2 IgG assay at ≥14 days from symptom onset: BTNX kit 1, 99%; BTNX kit 2, 94%; ACON, 99%; and SD, 100%. Specificity, measured using specimens collected prior to SARS-CoV-2 circulation in the United States and "cross-reactivity challenge" specimens, was 98% for BTNX kit 1 and ACON and 100% for BTNX kit 2 and SD. These results suggest that LFIAs may provide adequate results for rapid detection of SARS-CoV-2.


Subject(s)
Antibodies, Viral/blood , Betacoronavirus/immunology , Coronavirus Infections/diagnosis , Immunoassay/methods , Immunoglobulin G/blood , Pneumonia, Viral/diagnosis , COVID-19 , Humans , Pandemics , Retrospective Studies , Reverse Transcriptase Polymerase Chain Reaction/methods , SARS-CoV-2 , Sensitivity and Specificity
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