Characterization of antibody response to SARS-CoV-2 Orf8 from three waves of COVID-19 outbreak in Thailand.

A dynamic of virus adaptation and a mass vaccination campaign could significantly reduce the severity of clinical manifestations of COVID-19 and transmission. Hence, COVID-19 may become an endemic disease globally. Moreover, mass infection as the COVID-19 pandemic progressed affected the serology of the patients as a result of virus mutation and vaccination. Therefore, a need exists to acquire accurate serological testing to monitor the emergence of new outbreaks of COVID-19 to promptly prevent and control the disease spreading. In this study, the anti-Orf8 antibodies among samples collected in Thailand's first, fourth, and fifth waves of COVID-19 outbreaks compared with pre-epidemic sera were determined by indirect ELISA. The diagnostic sensitivity and specificity of the anti-Orf8 IgG ELISA for COVID-19 samples from the first, fourth, and fifth waves of outbreaks was found to be 100% compared with pre-epidemic sera. However, the diagnostic sensitivity and specificity of the anti-Orf8 IgG ELISA for a larger number of patient samples and controls from the fifth wave of outbreaks which were collected on day 7 and 14 after an RT-PCR positive result were 58.79 and 58.44% and 89.19 and 58.44%, respectively. Our data indicated that some of the controls might have antibodies from natural past infections. Our study highlighted the potential utility of anti-Orf8 IgG antibody testing for seroprevalence surveys but still warrants further investigations.

Sensitive and visual detection of SARS-CoV-2 using RPA-Cas12a one-step assay with ssDNA-modified crRNA.

BACKGROUND: CRISPR-Cas12a based one-step assays are widely used for nucleic acid detection, particularly for pathogen detection. However, the detection capability of the one-step assay is reduced because the Cas12a protein competes with the isothermal amplification enzymes for the target DNA and cleaves it. Therefore, the key to improving the sensitivity of the one-step assay is to address the imbalance between isothermal amplification and CRISPR detection. In previous study, we developed a Cas12a one-step assay using single-stranded DNA (ssDNA)-modified crRNA (mD-crRNA) and applied this method for the detection of pathogenic DNA. RESULTS: Here, we utilized mD-crRNA to establish a sensitive one-step assay that enables the visual detection of SARS-CoV-2 under ultraviolet light, achieving a detection limit of 5 aM without cross-reactivity. The sensitivity of mD-crRNA in the one-step assay was 100-fold higher than that of wild-type crRNA. Mechanistic studies revealed that the addition of ssDNA at the 3' end of mD-crRNA attenuates the binding affinity between the Cas12a-mD-crRNA complex and the target DNA. Consequently, this reduction in binding affinity decreases the cis-cleavage activity of Cas12a, mitigating its cleavage of the target DNA in the one-step assay. As a result, there is an augmentation in the amplification and accumulation of target DNA, thereby enhancing detection sensitivity. In the clinical testing of 40 SARS-CoV-2 RNA samples, the concordance between the results of the one-step assay and known qPCR results was 97.5 %. SIGNIFICANCE: The one-step assay using mD-crRNA proves to be highly sensitive and specificity and visually effective for the detection of SARS-CoV-2. Our study delves into the application of the mD-crRNA-mediated one-step assay in nucleic acid detection and its associated reaction mechanism. This holds great significance in addressing the inherent incompatibility issues between isothermal amplification and CRISPR detection.

Magnetic metal-organic frameworks as sensitive aptasensors for coronavirus spike protein.

Electrochemical biosensors, known for their low cost, sensitivity, selectivity, and miniaturization capabilities, are ideal for point-of-care devices. The magnetic metal-organic framework (MMOF), synthesized using the in-situ growth method, consists of ferric salt, magnetic nanoparticles, histidine, and benzene tetracarboxylic acid. MMOF was sequentially modified with aptamer-biotin and streptavidin-horseradish peroxidase, serving as a detector for spike protein and a transducer converting electrochemical signals using H2O2-hydroquinone on a screen-printed electrode. MMOF facilitates easy washing and homogeneous deposition on the working electrode with a magnet, enhancing sensitivity and reducing noise. The physical and electrochemical properties of the modified MMOFs were thoroughly characterized using various analytical techniques. The aptasensors' performance achieved a detection limit of 6 pM for voltammetry and 5.12 pM for impedance spectroscopy in human serum samples. This cost-effective, portable MMOF platform is suitable for rapid point-of-care testing for SARS-CoV-2 spike proteins.

Accelerated diagnosis: a crosslinking catalytic hairpin assembly system for rapid and sensitive SARS-CoV-2 RNA detection.

The COVID-19 pandemic has underscored the urgent need for rapid and reliable strategies for early detection of SARS-CoV-2. In this study, we propose a DNA nanosphere-based crosslinking catalytic hairpin assembly (CCHA) system for the rapid and sensitive SARS-CoV-2 RNA detection. The CCHA system employs two DNA nanospheres functionalized with catalytic hairpin assembly (CHA) hairpins. The presence of target SARS-CoV-2 RNA initiated the crosslinking of DNA nanospheres via CHA process, leading to the amplification of fluorescence signals. As a result, the speed of SARS-CoV-2 diagnosis was enhanced by significantly increasing the local concentration of the reagents in a crosslinked DNA product, leading to a detection limit of 363 fM within 5 min. The robustness of this system has been validated in complex environments, such as fetal bovine serum and saliva. Hence, the proposed CCHA system offers an efficient and simple approach for rapid detection of SARS-CoV-2 RNA, holding substantial promise for enhancing COVID-19 diagnosis.

Optical biosensors for diagnosis of COVID-19: nanomaterial-enabled particle strategies for post pandemic era.

The COVID-19 pandemic underlines the need for effective strategies for controlling virus spread and ensuring sensitive detection of SARS-CoV-2. This review presents the potential of nanomaterial-enabled optical biosensors for rapid and low-cost detection of SARS-CoV-2 biomarkers, demonstrating a comprehensive analysis including colorimetric, fluorescence, surface-enhanced Raman scattering, and surface plasmon resonance detection methods. Nanomaterials including metal-based nanomaterials, metal-organic frame-based nanoparticles, nanorods, nanoporous materials, nanoshell materials, and magnetic nanoparticles employed in the production of optical biosensors are presented in detail. This review also discusses the detection principles, fabrication methods, nanomaterial synthesis, and their applications for the detection of SARS-CoV-2 in four categories: antibody-based, antigen-based, nucleic acid-based, and aptamer-based biosensors. This critical review includes reports published in the literature between the years 2021 and 2024. In addition, the review offers critical insights into optical nanobiosensors for the diagnosis of COVID-19. The integration of artificial intelligence and machine learning technologies with optical nanomaterial-enabled biosensors is proposed to improve the efficiency of optical diagnostic systems for future pandemic scenarios.

[Clinical and morphological features of lung injury long-term after SARS-CoV-2 recovery].

AIM: To study the clinical and histological profile of lung tissue in patients with persistent pulmonary disease, respiratory symptoms and CT findings after SARS-CoV-2 infection. MATERIALS AND METHODS: The study included 15 patients (7 females and 8 males) with a mean age of 57.7 years. All patients underwent laboratory tests, chest computed tomography, echocardiography, and pulmonary function tests. Pulmonary tissue and bronchoalveolar lavage samples were obtained by fibrobronchoscopy, transbronchial forceps (2 patients), and lung cryobiopsy (11 patients); open biopsy was performed in 2 patients. Cellular composition, herpesvirus DNA, SARS-CoV-2, Mycobacterium tuberculosis complex, galactomannan optical density index, and bacterial and fungal microflora growth were determined in bronchoalveolar lavage. SARS-CoV-2 was also identified in samples from the nasal mucosa, throat and feces using a polymerase chain reaction. RESULTS: The results showed no true pulmonary fibrosis in patients recovered from SARS-CoV-2 infection with persistent respiratory symptoms, functional impairment, and CT findings after SARS-CoV-2 infection. The observed changes comply with the current and/or resolving infection and inflammatory process. CONCLUSION: Thus, no true pulmonary fibrosis was found in patients after SARS-CoV-2 infection with persistent respiratory symptoms, functional impairment, and CT findings. The observed changes comply with the current and/or resolving infection and inflammatory process.

[The role of spectral analysis of cough sounds in the diagnosis of COVID-19].

AIM: To evaluate the possibility of using spectral analysis of cough sounds in the diagnosis of a new coronavirus infection COVID-19. MATERIALS AND METHODS: Spectral toussophonobarography was performed in 218 patients with COVID-19 [48.56% men, 51.44% women, average age 40.2 (32.4; 51.0)], in 60 healthy individuals [50% men, 50% women, average age 41.7 (32.2; 53.0)] with induced cough (by inhalation of citric acid solution at a concentration of 20 g/l through a nebulizer). The recording was made using a contact microphone located on a special tripod at a distance of 15-20 cm from the face of the subject. The resulting recordings were processed in a computer program, after which spectral analysis of cough sounds was performed using Fourier transform algorithms. The following parameters of cough sounds were evaluated: the duration of the cough act (ms), the ratio of the energy of low frequencies (60-600 Hz) to the energy of high frequencies (600-6000 Hz), the frequency of the maximum energy of the cough sound (Hz). RESULTS: After statistical processing, it was found out that the parameters of the cough sound of COVID-19 patients differ from the cough of healthy individuals. The obtained data were substituted into the developed regression equation. Rounded to integers, the resulting number had the following interpretation: "0" - there is no COVID-19, "1" - there is COVID-19. CONCLUSION: The technique showed high levels of sensitivity and specificity. In addition, the method is characterized by sufficient ease of use and does not require expensive equipment, therefore it can be used in practice for timely diagnosis of COVID-19.

An Immiscible-Phase Filtration Device for Isolation, Amplification, and Detection of Nucleic Acids for Clinical Diagnostics.

Clinical diagnostics of infectious diseases via nucleic acid amplification tests (NAATs) depend on a separate step of isolation of nucleic acids from cells/viruses embedded in complex biological matrices. The most recent example has been reverse transcription polymerase chain reaction (RT-PCR) for amplification and detection of SARS-CoV-2 RNA for COVID-19 diagnostics. Kits for RNA extraction and purification are commercially available; however, their integration with amplification systems is generally lacking, resulting in two separate steps, i.e., sample preparation and amplification. This makes NAATs more time-consuming, requiring skilled personnel, and can increase the likelihood of contamination. Here, we describe a setup and methodology to perform the quick extraction and detection of nucleic acids in an integrated manner. In particular, we focus on the use of an immiscible filtration device for capture, isolation, concentration, amplification, and colorimetric detection of SARS-CoV-2 RNA.

Evaluation of blood pressure variation in recovered COVID-19 patients at one-year follow-up: a retrospective cohort study.

BACKGROUND: Coronavirus disease 2019 (COVID-19) has various sequelae, one of which might be hypertension. We aimed to evaluate COVID-19's impact on blood pressure (BP) in non-hospitalized patients at one-year follow-up. METHOD: A total of 7,950 consecutive COVID-19 patients regularly visiting our cardiology clinic were retrospectively screened. Patients' electronic medical records including demographics, comorbidities, vital signs, treatments, and outcomes, were reviewed by two physicians. Individuals with at least one BP measurement in the three months preceding COVID-19 and one measurement in 12 months or more following recovery were included. BP levels before and after COVID-19 were compared using the paired t-test. RESULTS: 5,355 confirmed COVID-19 patients (mean age 55.51 ± 15.38 years) were included. Hypertension (56.9%) and diabetes mellitus (34%) were the predominant comorbidities, and 44.3% had prior major adverse cardiovascular events. Both systolic (126.90 ± 20.91 vs. 139.99 ± 23.94 mmHg, P < 0.001) and diastolic BP (80.54 ± 13.94 vs. 86.49 ± 14.40 mmHg, P < 0.001) were significantly higher post-COVID-19 vs. pre-COVID-19. Notably, 456 (14%) hypertensive patients experienced exacerbated hypertension, while 408 (17%) patients developed new-onset hypertension, overall 864 (16%) of patients had exacerbation or new hypertension. Linear regression analysis revealed that advanced age, smoking, previous cardiovascular events, hypertension, and diabetes mellitus predict increased BP following COVID-19 (P < 0.001). CONCLUSION: COVID-19 raised systolic and diastolic BP in the long term in non-hospitalized patients, with over one-sixth developing new-onset or exacerbated hypertension. All patients should be evaluated regarding BP, following COVID-19 recovery, particularly those with the mentioned predictive factors. (clinicaltrial.gov: NCT05798208).

Oesophageal cell collection device and biomarker testing to identify high-risk Barrett's patients requiring endoscopic investigation.

BACKGROUND: Barrett's oesophagus surveillance places significant burden on endoscopy services yet is vital to detect early cancerous change. Oesophageal cell collection device (OCCD) testing was introduced across Scotland for Barrett's surveillance in response to the COVID-19 pandemic. This national pragmatic retrospective study presents the CytoSCOT programme results and evaluates whether OCCD testing is successfully identifying high-risk Barrett's patients requiring urgent endoscopy. METHODS: All patients undergoing OCCD testing for Barrett's surveillance across 11 Scottish health boards over a 32-month period were identified. Patients who underwent endoscopy within 12 months of OCCD test were included. Individual patient records were interrogated to record clinical information and OCCD test result to categorize patients into risk groups. Endoscopic histopathology results were analysed according to risk group and segment length. Patients were deemed high risk if the OCCD test demonstrated atypia and/or p53 positivity. RESULTS: 4204 OCCD tests were performed in 3745 patients: 608 patients underwent endoscopy within 12 months and were included in this analysis. Patients with longer Barrett's segments were significantly more likely to have an abnormal OCCD test. 50/608 patients (8.2%) had high-grade dysplasia or cancer on endoscopic biopsies: this equates to 1.3% of the total group (50/3745). 46/50 patients (92.0%) were deemed high risk, triggering urgent endoscopy: this rose to 100% with insufficient tests removed. There were no cancers diagnosed within 12 months post-OCCD in the low-risk group. CONCLUSION: OCCD testing is an effective triage tool to identify high-risk patients with Barrett's oesophagus requiring further investigation with endoscopy within the real-world setting.

Hematological Parameters and Comorbidities in COVID-19: Insights into Clinical Profiles and Outcome Predictors.

BACKGROUND: The global pandemic, known as the coronavirus disease 2019 (COVID-19) and caused by the severe acute respiratory syndrome, coronavirus 2 (SARS-CoV-2), poses a significant threat, particularly to individuals with comorbidities such as hypertension, chronic obstructive pulmonary disease (COPD), diabetes, HIV, cardiovascular disease (CVD), and cancer. METHODS: This descriptive retrospective study investigates the impact of comorbidities on COVID-19-positive patients. The study includes individuals that were tested positive for SARS-CoV-2 via polymerase chain reaction at the Security Forces Hospital, Makkah, KSA, between February, 2022, and June, 2022. A total of 208 patients (107 males, 101 females) were examined, and the laboratory results revealed normal parameters. RESULTS: An analysis indicates that 86.5% of the patients were discharged, 2.9% remained hospitalized, and 10.6% succumbed to the disease, indicating a 10.6% mortality rate among comorbid COVID-19-positive patients. Notably, the study identifies specific comorbidities (chronic kidney disease, diabetes mellitus, hypertension) and changes in laboratory parameters (red blood cells, hemoglobin, C-reactive protein, white blood cells, ferritin, D-dimer, ALT, troponin, LDH, neutrophils) associated with ICU admission during hospitalization. CONCLUSIONS: This study underscores the critical impact of comorbidities, such as chronic kidney disease, diabetes, and hypertension, on the clinical outcomes of COVID-19-positive patients. The identification of specific laboratory parameters linked with ICU admission provides valuable insights for risk stratification and tailored management strategies.

SARS-CoV-2 Infection Increases High Risk Rate of Down Syndrome Screening Test by Reducing Alpha-Fetoprotein.

BACKGROUND: The coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has been a significant global health issue in recent years. Numerous studies indicate that COVID-19 during pregnancy is associated with an increased likelihood of pregnancy complications. Additionally, pregnancy itself is known to elevate the risk of severe SARS-CoV-2 infection. To explore the potential impact of SARS-CoV-2 infection on the probability of Down syndrome in fetuses, we conducted serological testing of Down syndrome markers in pregnant women who had contracted the virus. METHODS: Serological experiments were conducted utilizing a particle chemiluminescence test. The cohort of pregnant women was categorized into three groups: a control group with no infection, a group infected with SARS-CoV-2 Omicron within the first six weeks of gestation, and a group infected beyond the sixth week of gestation. RESULTS: In the group of individuals infected within 6 gestational weeks, the infection resulted in a decrease in alpha-fetoprotein (AFP) levels and a higher positive rate of Down syndrome screening tests (p ˂ 0.05). However, in this study, SARS-CoV-2 infection did not lead to an increase in the occurrence of Down syndrome in the fetus. The positive rate of women infected beyond 6 gestational weeks was slightly higher than the non-infected group (6.2% vs. 5.7%), but these differences were not statistically significant (p > 0.05). Within the group infected beyond 6 gestational weeks, there was, compared to the control group, a decrease in free beta human chorionic gonadotropin (ß-hCG) levels (p < 0.05). CONCLUSIONS: This study presents a novel investigation into the impact of SARS-CoV-2 infection on AFP and ß-hCG levels. It has been observed that pregnant women who contract SARS-CoV-2 may exhibit an increased likelihood of positive results in serum tests conducted for Down syndrome screening. However, it is important to note that the occurrence of Down syndrome in the developing fetus does not appear to be elevated. To validate these findings, additional research involving larger and diverse cohorts is necessary.

Strategic Retesting to Reduce False Positive SARS-CoV-2 PCR Test Results.

BACKGROUND: Nucleic acid amplification testing is the gold standard for SARS-CoV-2 diagnostics, although it may produce a certain number of false positive results. There has not been much published about the characteristics of false positive results. In this study, based on retesting, specimens that initially tested positive for SARS-CoV-2 were classified as true or false positive groups to characterize the distribution of cycle threshold (CT) values for N1 and N2 targets and number of targets detected for each group. METHODS: Specimens that were positive for N-gene on retesting and accompanied with S-gene were identified as true positives (true positive based on retesting, rTP), while specimens that retested negative were classified as false positives (false positive based on retesting, rFP). RESULTS: Of the specimens retested, 85/127 (66.9%) were rFP, 16/47 (34.0%) specimens with both N1 and N2 targets initially detected were rFP, and the CT values for each target was higher in rFP than in rTP. ROC curve analysis showed that optimal cutoff values of CT to differentiate between rTP and rFP were 34.8 for N1 and 33.0 for N2. With the optimal cutoff values of CT for each target, out of the 24 specimens that were positive for both N1 and N2 targets and classified as rTP, 23 (95.8%) were correctly identified as true positives. rFP specimens had a single N1 target in 52/61 (85.2%) and a single N2 target in 17/19 (89.5%). Notably, no true positive results were obtained from any specimens with only N2 target detected. CONCLUSIONS: These results suggest that retesting should be performed for positive results with a CT value greater than optimal cutoff value for each target or with a single N1 target amplified, considering the possibility of a false positive. This may provide guidance on indications to perform retesting to minimize the number of false positives.

Contributing Factors Affecting the Length of Hospital Stay among Febrile Patients with Omicron Reported in Suzhou.

BACKGROUND: Coronavirus disease 2019 (COVID-19) has had global attention with regard to the urgent challenging threat to global public health. Currently, the novel Omicron variant is showing rapid transmission across the world, which appears to be more contagious than the previous variants of COVID-19. Early recognition of disease is critical for patients' prognosis. Fever is the most common symptom. We evaluated the clinical characteristics of febrile patients with COVID-19 reported in Suzhou and explored the predictors for a longer duration of hospitalization in febrile patients. METHODS: This retrospective study was carried out in 146 Omicron variant infected patients confirmed by nucleic acid tests in the Affiliated Infectious Hospital of Soochow University between February 13, 2022 and March 2, 2022. Data of febrile and afebrile laboratory-confirmed patients on hospital admission in Suzhou were collected and compared. According to the median length of stay (LOS), febrile cases were divided into short and long LOS groups. Then the predictive factors for a prolonged duration of hospitalization were analyzed using logistic regression methods. Receiver Operating Characteristic (ROC) Curve analysis was used to analyze the effectiveness of the risk factors for prolonged duration of hospitalization in febrile COVID-19 patients. RESULTS: Of the 146 discharged patients in our study, 112 patients (76.7%) caught a fever. Compared to afebrile Omicron patients, febrile patients showed a significantly longer duration of hospitalization (15.00 (5.80) vs. 13.00 (6.00), p = 0.002). Taking the median LOS (15 days) as the dividing point, 64 febrile cases were assigned to the short LOS group and the rest to the long LOS group. The long LOS group had a longer virus shedding duration than the short LOS group (18.42 ± 2.86 vs. 11.94 ± 2.50 days, p < 0.001). Compared to short LOS febrile patients, long LOS patients were older (44.88 ± 21.36 vs. 30.89 ± 17.95 years, p < 0.001) and showed a higher proportion of greater than 60 years old (33.3% vs. 9.4%, p = 0.002; Supplemental Table S2). Febrile patients with long LOS also showed a higher proportion of hypertension (25% vs. 6.3%, p = 0.005) and higher levels of cTnI (5.00 (3.00) vs. 4.00 (2.00) µg/L, p = 0.025). The multivariate analysis indicated that virus shedding duration (OR 2.369, 95% CI 1.684 - 3.333, p < 0.001) was the independent risk factor associated with long-term hospital stay in febrile patients with Omicron. Furthermore, ROC Curve analysis revealed that the area under the curve (AUC) for virus shedding duration to diagnose prolonged duration of hospitalization in febrile COVID-19 patients was 0.951 (95% CI 0.913 - 0.989). The cutoff point was set at 14.5 days. CONCLUSIONS: More than half of the non-severe patients exposed to the new Omicron variant had symptoms of fever. In total, 42.86% of the febrile patients were discharged within 15 days since hospital admission. Febrile Omicron cases took a longer duration of hospitalization compared to afebrile patients, and virus shedding duration (OR 2.369, 95% CI 1.684 - 3.333, p < 0.001) was probably a predictive factor for long-term hospital stays.

A Prediction Model for Prolonged Hospital Length of Stay (ProLOS) in Coronavirus Disease 2019 (COVID-19) Patients.

BACKGROUND: Coronavirus disease 2019 (COVID-19) is an acute respiratory infectious disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). With the normalization of COVID-19 globally, it is crucial to construct a prediction model that enables clinicians to identify patients at risk for ProLOS based on demographics and serum inflammatory biomarkers. METHODS: The study included hospitalized patients with a confirmed diagnosis of COVID-19. These patients were randomly grouped into a training (80%) and a test (20%) cohort. The LASSO regression and ten-fold cross-validation method were applied to filter variables. The training cohort utilized multifactorial logistic regression analyses to identify the independent factors of ProLOS in COVID-19 patients. A 4-variable nomogram was created for clinical use. ROC curves were plotted, and the area under the curve (AUC) was calculated to evaluate the model's discrimination; calibration analysis was planned to assess the validity of the nomogram, and decision curve analysis (DCA) was used to evaluate the clinical usefulness of the model. RESULTS: The results showed that among 310 patients with COVID-19, 80 had extended hospitalization (80/310). Four independent risk factors for COVID-19 patients were identified: age, coexisting chronic respiratory diseases, white blood cell count (WBC), and serum albumin (ALB). A nomogram based on these variables was created. The AUC in the training cohort was 0.808 (95% CI: 0.75 - 0.8671), and the AUC in the test cohort was 0.815 (95% CI: 0.7031 - 0.9282). The model demonstrates good calibration and can be used with threshold probabilities ranging from 0% to 100% to obtain clinical net benefits. CONCLUSIONS: A predictive model has been created to accurately predict whether the hospitalization duration of COVID-19 patients will be prolonged. This model incorporates serum WBC, ALB levels, age, and the presence of chronic respiratory system diseases.