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1.
BMC Infect Dis ; 22(1): 859, 2022 Nov 17.
Article in English | MEDLINE | ID: covidwho-2139175

ABSTRACT

BACKGROUND: Lyme borreliosis (LB) is the most common tick-borne infectious disease in the northern hemisphere. The diagnosis of LB is usually made by clinical symptoms and subsequently supported by serology. In Europe, a two-step testing consisting of an enzyme-linked immunosorbent assay (ELISA) and an immunoblot is recommended. However, due to the low sensitivity of the currently available tests, antibody detection is sometimes inaccurate, especially in the early phase of infection, leading to underdiagnoses. METHODS: To improve upon Borrelia diagnostics, we developed a multiplex Borrelia immunoassay (Borrelia multiplex), which utilizes the new INTELLIFLEX platform, enabling the simultaneous dual detection of IgG and IgM antibodies, saving further time and reducing the biosample material requirement. In order to enable correct classification, the Borrelia multiplex contains eight antigens from the five human pathogenic Borrelia species known in Europe. Six antigens are known to mainly induce an IgG response and two antigens are predominant for an IgM response. RESULTS: To validate the assay, we compared the Borrelia multiplex to a commercial bead-based immunoassay resulting in an overall assay sensitivity of 93.7% (95% CI 84.8-97.5%) and a specificity of 96.5% (95%CI 93.5-98.1%). To confirm the calculated sensitivity and specificity, a comparison with a conventional 2-step diagnostics was performed. With this comparison, we obtained a sensitivity of 95.2% (95% CI 84.2-99.2%) and a specificity of 93.0% (95% CI 90.6-94.7%). CONCLUSION: Borrelia multiplex is a highly reproducible cost- and time-effective assay that enables the profiling of antibodies against several individual antigens simultaneously.


Subject(s)
Borrelia , Lyme Disease , Humans , Antibodies, Bacterial , Serologic Tests/methods , Immunoglobulin G , Lyme Disease/diagnosis , Immunoglobulin M
2.
Int J Infect Dis ; 111: 5-9, 2021 Oct.
Article in English | MEDLINE | ID: covidwho-2113670

ABSTRACT

OBJECTIVE: The aim of this study was to investigate the infectiousness of re-positive coronavirus disease 2019 (COVID-19) patients. METHODS: All nucleic acid testing (NAT) was performed using throat swabs, nasopharyngeal swabs, and anal swabs, which were tested by Fluorescent quantitative realtime PCR. Re-positive cases were defined as a discharged patient who re-tested positive by NAT. Micro-neutralization of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was performed based on the methods for severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS) viruses. IgM and IgG against the N protein of SARS-CoV-2 were determined by ELISA. RESULTS: A total 255 (16.04%) of 1590 COVID-19 patients were re-positive. The re-positive cases were more likely to occur in patients in the 20-39 years age group and in patients with disease of moderate severity. Quantitative PCR showed that cycle threshold (Ct) values and viral loads were both far lower than in the hospitalized COVID-19 patients. The viral load in re-positive cases was very low. Viral culture of the samples from re-positive patients showed no cytopathic effect, and NAT of the culture medium of viral cultures all exhibited negative results. CONCLUSION: The viral load in re-positive cases was very low; patients were not infectious and the risk of human-to-human transmission was extremely low. Discharged COVID-19 patients should undergo home health management for 3 weeks.


Subject(s)
COVID-19 , Humans , Real-Time Polymerase Chain Reaction , SARS-CoV-2 , Serologic Tests , Viral Load
3.
Rev Assoc Med Bras (1992) ; 68(3): 344-350, 2022 Mar.
Article in English | MEDLINE | ID: covidwho-2114224

ABSTRACT

BACKGROUND: Coronavirus disease 2019, which is caused by the new severe acute respiratory syndrome coronavirus 2, became a pandemic in 2020 with a mortality rate of 2% and high transmissibility, thus making studies with an epidemiological profile essential. OBJECTIVES: The aim of this study was to characterize the population that performed the severe acute respiratory syndrome coronavirus 2 molecular and serological tests in Carlos Chagas Laboratory - Sabin Group in Cuiabá. METHODS: A retrospective cross-sectional study was carried out with all the samples collected from nasal swab tested by RT-PCR and serological for severe acute respiratory syndrome coronavirus 2 IgM/IgG from the population served between April and December 2020. FINDINGS: In the analysis period, 23,631 PCR-coronavirus disease 2019 examinations were registered. Of this total number of cases, 7,649 (32.37%) tested positive, while 15,982 (66.31%) did not detect viral RNA and 374 of the results as undetermined. The peak of positive RT-PCR performed in July (n=5,878), with 35.65% (n=2,096). A total of 8,884 tests were performed on serological test SOROVID-19, with a peak of 1,169 (57.16%) of the positive tests for severe acute respiratory syndrome coronavirus 2 in July. MAIN CONCLUSIONS: Molecular positivity and serological tests, both peaked in July 2020, were mostly present in women aged 20-59 years, characterizing Cuiabá as the epicenter of the Midwest region in this period due to the high rate of transmissibility of severe acute respiratory syndrome coronavirus 2.


Subject(s)
COVID-19 , SARS-CoV-2 , Antibodies, Viral , COVID-19/diagnosis , COVID-19/epidemiology , Cross-Sectional Studies , Female , Humans , Immunoglobulin G , Immunoglobulin M , Prevalence , Retrospective Studies , Serologic Tests/methods
5.
J Infect Dev Ctries ; 16(9): 1376-1384, 2022 09 30.
Article in English | MEDLINE | ID: covidwho-2066666

ABSTRACT

The diagnosis of COVID-19 is considered a significant step in the management of the disease that is causing a major worldwide public health challenge from the time of its emergence in December 2019. Since it has been established that SARS-CoV-2 spreads rapidly, timely detection of the positive cases and isolation of such individuals and their contacts helps in containing viral transmission. In this paper, we review the in vitro technology platforms for testing and diagnosing COVID-19 patients: molecular tests, rapid antigen tests, and serology tests. As part of our review of each category of tests, we discuss the commercialized testing platforms, their analyzing systems, specimen collection protocols, and testing methodologies. Moreover, the efficacy and limitations of each technique are also discussed. The key structural components of the virus are presented to provide an understanding of the scientific principles behind the testing tools.


Subject(s)
COVID-19 , COVID-19/diagnosis , COVID-19 Testing , Clinical Laboratory Techniques/methods , Humans , SARS-CoV-2 , Serologic Tests/methods
6.
PLoS One ; 17(9): e0273818, 2022.
Article in English | MEDLINE | ID: covidwho-2039402

ABSTRACT

BACKGROUND: The SARS-CoV-2 pandemic is a global threat affecting 210 countries, with 2,177,469 confirmed cases and 6.67% case fatality rate as of April 16, 2020. In Africa, 17,243 cases have been confirmed, but many remain undiagnosed due to limited laboratory-capacity, suboptimal performance of used molecular-assays (~30% false negative, Yu et al. and Zhao et al., 2020) and limited WHO-recommended rapid-tests. OBJECTIVES: We aim to implement measures to minimize risks for COVID-19 in Cameroon, putting together multidisciplinary highly-experienced virologists, immunologists, bioinformaticians and clinicians, to achieve the following objectives: (a) to integrate/improve available-infrastructure, methodologies, and expertise on COVID-19. For this purpose, we will create a platform enabling researchers/clinicians to better integrate and translate evidence into the COVID-19 clinical-practice; (b) to enhance capacities in Cameroon for screening/detecting individuals with high-risks of COVID-19, by setting-up effective core-facilities on-site; (c) to validate point-of-care SARS-CoV-2 molecular assays allowing same-day result delivery, thus permitting timely diagnosis, treatment, and retention in care of COVID-19 patients; (d) to implement SARS-CoV-2 diagnosis with innovative/highly sensitive ddPCR-based assays and viral genetic characterization; (e) to validate serological assays to identify COVID-19-exposed persons and follow-up of convalescents. METHODS: This is a prospective, observational study conducted among COVID-19 suspects/contacts during 24 months in Cameroon. Following consecutive sampling of 1,536 individuals, oro/nasopharyngeal swabs and sera will be collected. Well characterised biorepositories will be established locally; molecular testing will be performed on conventional real-time qPCR, point-of-care GeneXpert, antigen-tests and digital droplet PCR (ddPCR); SARS-CoV2 amplicons will be sequenced; serological testing will be performed using ELISA, and antibody-based kits. Sensitivity, specificity, positive- and negative-predictive values will be evaluated. EXPECTED OUTCOMES: These efforts will contribute in creating the technical and clinical environment to facilitate earlier detection of Sars-CoV-2 in Africa in general and in Cameroon in particular. Specifically, the goals will be: (a) to implement technology transfer for capacity-building on conventional and point-of-care molecular assays, achieving a desirable performance for clinical diagnosis of SARS-CoV2; (b) to integrate/improve the available infrastructure, methodologies, and expertise on Sars-CoV2 detection; (c) to improve the turn-around-time for diagnosing COVID-19 infection with obvious advantage for patients/clinical management thanks to low-cost assays, thus permitting timely treatment and retention in care; (d) to assess the epidemiology of COVID-19 and circulating-variants in Cameroon as compared to strains found in other countries.


Subject(s)
COVID-19 , SARS-CoV-2 , COVID-19/diagnosis , COVID-19 Testing , Cameroon/epidemiology , Humans , Observational Studies as Topic , RNA, Viral , Sensitivity and Specificity , Serologic Tests/methods
7.
J Infect Chemother ; 28(11): 1590-1593, 2022 Nov.
Article in English | MEDLINE | ID: covidwho-2036255

ABSTRACT

INTRODUCTION: Compared to nasopharyngeal swabs (NPS), there has been insufficient evaluation of the diagnostic performance of nasal swabs (NS) for the detection of severe acute respiratory coronavirus 2 (SARS-CoV-2) in the nucleic acid amplification test (NAAT) and quantitative SARS-CoV-2 antigen test (QAT). METHODS: We prospectively compared healthcare worker-collected and flocked NS within nine days after symptom onset to paired NPS to detect SARS-CoV-2 in NAAT and QAT on the fully automated Lumipulse system. The agreement between sample types was evaluated, and cycle threshold (Ct) values and antigen levels were used as surrogate viral load measures. RESULTS: Sixty sets of NPS and NS samples were collected from 40 patients with COVID-19. The overall agreements between NAAT and QAT samples were 76.7% and 65.0%, respectively. In NAAT, the Ct value of NS was significantly higher, 5.9, than that of NPS. Thirty-nine (95.1%) NS tested positive in 41 positive-paired NPS with Ct ≤ 30. The negative correlation was observed between antigen levels of NS in QAT and Ct values of NS in NAAT (r = -0.88). In QAT, the antigen level of NS was significantly lower than that of NPS. Thirty-six (90.0%) NS tested positive in 40 positive-paired NPS with antigen levels >100 pg/mL, which were collected significantly earlier than those with antigen levels ≤100 pg/mL. CONCLUSIONS: In NAAT and QAT, NS had limited performance in detecting SARS-CoV-2 compared to NPS. However, NS may be helpful for patients with COVID-19 with high viral loads or those in the early stages of the illness.


Subject(s)
COVID-19 , SARS-CoV-2 , COVID-19/diagnosis , COVID-19 Testing , Humans , Nasopharynx , Nucleic Acid Amplification Techniques , SARS-CoV-2/genetics , Sensitivity and Specificity , Serologic Tests , Viral Load
8.
Anal Biochem ; 658: 114902, 2022 12 01.
Article in English | MEDLINE | ID: covidwho-2031059

ABSTRACT

The development of the Coronavirus disease 2019 (COVID-19) vaccine is one of the most important efforts in controlling the pandemic. Serological tests are used to identify highly reactive human donors for convalescent plasma therapy, measuring vaccine efficacy and durability. This review article presents a review of serology tests and how antibody titers in response to vaccines have been developed. Some of the serological test methods discussed are Plaque Reduction Neutralization Test (PRNT), Enzyme-Linked Immunosorbent Assay (ELISA), Lateral flow immunoassay (LFIA), chemiluminescent immunoassay (CLIA), and Chemiluminescent Micro-particle Immunoassay (CMIA). This review can provide an understanding of the application of the body's immune response to vaccines to get some new strategies for vaccines.


Subject(s)
COVID-19 , SARS-CoV-2 , Humans , COVID-19/diagnosis , COVID-19/prevention & control , Clinical Laboratory Techniques/methods , Antibodies, Viral , Serologic Tests/methods , Enzyme-Linked Immunosorbent Assay/methods , Vaccination , Antibodies, Neutralizing
9.
PLoS One ; 17(6): e0265816, 2022.
Article in English | MEDLINE | ID: covidwho-2021634

ABSTRACT

We probed the transmission of COVID-19 by applying an airborne transmission model to five well-documented case studies-a Washington state church choir, a Korean call center, a Korean exercise class, and two different Chinese bus trips. For all events the likely index patients were pre-symptomatic or mildly symptomatic, which is when infective patients are most likely to interact with large groups of people. Applying the model to those events yields results that suggest the following: (1) transmission was airborne; (2) superspreading events do not require an index patient with an unusually high viral load; (3) the viral loads for all of the index patients were of the same order of magnitude and consistent with experimentally measured values for patients at the onset of symptoms, even though viral loads across the population vary by a factor of >108. In particular we used a Wells-Riley exposure model to calculate q, the total average number of infectious quanta inhaled by a person at the event. Given the q value for each event, the simple airborne transmission model was used to determined Sq, the rate at which the index patient exhaled infectious quanta and N0, the characteristic number of COVID-19 virions needed to induce infection. Despite the uncertainties in the values of some parameters of the superspreading events, all five events yielded (N0∼300-2,000 virions), which is similar to published values for influenza. Finally, this work describes the conditions under which similar methods can provide actionable information on the transmission of other viruses.


Subject(s)
COVID-19 , Influenza, Human , COVID-19/epidemiology , Exhalation , Humans , Serologic Tests , Viral Load
10.
Sci Rep ; 12(1): 14637, 2022 08 27.
Article in English | MEDLINE | ID: covidwho-2016832

ABSTRACT

Determining accurate estimates for the characteristics of the severe acute respiratory syndrome coronavirus 2 in the upper and lower respiratory tracts, by fitting mathematical models to data, is made difficult by the lack of measurements early in the infection. To determine the sensitivity of the parameter estimates to the noise in the data, we developed a novel two-patch within-host mathematical model that considered the infection of both respiratory tracts and assumed that the viral load in the lower respiratory tract decays in a density dependent manner and investigated its ability to match population level data. We proposed several approaches that can improve practical identifiability of parameters, including an optimal experimental approach, and found that availability of viral data early in the infection is of essence for improving the accuracy of the estimates. Our findings can be useful for designing interventions.


Subject(s)
COVID-19 , Humans , Models, Theoretical , SARS-CoV-2 , Serologic Tests , Viral Load
11.
Lancet Infect Dis ; 22(9): 1264-1265, 2022 09.
Article in English | MEDLINE | ID: covidwho-2016273
12.
Int J Infect Dis ; 122: 576-584, 2022 Sep.
Article in English | MEDLINE | ID: covidwho-2015433

ABSTRACT

OBJECTIVES: Observing the serological cross-reactivity between SARS-CoV-2 and dengue virus (DV), we aimed to elucidate its effect on dengue serodiagnosis and infectivity in a highly dengue-endemic city in India. METHODS: A total of 52 COVID-19 (reverse transcription-polymerase chain reaction [RT-PCR] positive) serum samples were tested in rapid lateral flow immunoassays and DV immunoglobulin G (IgG) enzyme-linked immunosorbent assay (ELISA) to detect DV or SARS-CoV-2 IgG/immunoglobulin M. The COVID-19 antibody (Ab) positive samples were subjected to a virus neutralization test (Huh7 cells) using DV type 1 (DV1) clinical isolate. RESULTS: Most (93%) of the SARS-CoV-2 Ab-positive serum samples cross-reacted with DV in rapid or ELISA tests. All were DV RNA and nonstructural protein 1 (NS1) antigen-negative. COVID-19 serum samples that were DV cross-reactive neutralized DV1. Of these, 57% had no evidence of DV pre-exposure (DV NS1 Ab-negative). The computational study also supported potential interactions between SARS-CoV-2 Ab and DV1. CONCLUSION: DV serodiagnosis will be inconclusive in areas co-endemic for both viruses. The COVID-19 pandemic appears to impart a protective response against DV in DV-endemic populations.


Subject(s)
COVID-19 , Dengue Virus , Dengue , Antibodies, Viral , COVID-19/diagnosis , Enzyme-Linked Immunosorbent Assay , Humans , Immunoglobulin G , Immunoglobulin M , Neutralization Tests , Pandemics , SARS-CoV-2 , Sensitivity and Specificity , Serologic Tests
13.
Tuberculosis (Edinb) ; 136: 102253, 2022 09.
Article in English | MEDLINE | ID: covidwho-2004564

ABSTRACT

Tuberculosis (TB) stays a major cause of death globally after COVID-19 and HIV. An early diagnosis to control TB effectively, needs a fast reliable diagnostic method with high sensitivity. Serodiagnosis involving polyclonal antibodies detection against an antigen of Mycobacterium tuberculosis (Mtb) in serum samples can be instrumental. In our study, Rv3874 and Rv3875 antigens were cloned, expressed, and purified individually and as a chimeric construct in Escherichia coli BL21. Enzyme-Linked Immunosorbent Assay (ELISA) based findings revealed that the Rv3874-Rv3875 chimeric construct was two-fold more sensitive (59.7%) than the individual sensitivities of Rv3874 (28.4%) and Rv3875 (24.9%) for 201 serum TB positive samples. Furthermore, the fusion construct was a little more sensitive (60.4%) for male subjects than that for females (58.8%). Lastly, our preliminary findings, molecular insights of secondary structure, and statistical and in silico analysis of each construct also advocate that CEP can be considered a better immunodiagnostic tool in addition to previously reported EC skin test.


Subject(s)
COVID-19 , Mycobacterium tuberculosis , Tuberculosis , Antigens, Bacterial , Enzyme-Linked Immunosorbent Assay/methods , Escherichia coli , Female , Humans , Male , Mycobacterium tuberculosis/genetics , Recombinant Fusion Proteins/genetics , Recombinant Fusion Proteins/metabolism , Sensitivity and Specificity , Serologic Tests , Tuberculosis/diagnosis
14.
Int J Mol Sci ; 23(17)2022 Aug 24.
Article in English | MEDLINE | ID: covidwho-1997650

ABSTRACT

Serological assays are useful in investigating the development of humoral immunity against SARS-CoV-2 in the context of epidemiological studies focusing on the spread of protective immunity. The plaque reduction neutralization test (PRNT) is the gold standard method to assess the titer of protective antibodies in serum samples. However, to provide a result, the PRNT requires several days, skilled operators, and biosafety level 3 laboratories. Therefore, alternative methods are being assessed to establish a relationship between their outcomes and PRNT results. In this work, four different immunoassays (Roche Elecsys® Anti SARS-CoV-2 S, Snibe MAGLUMI® SARS-CoV-2 S-RBD IgG, Snibe MAGLUMI® 2019-nCoV IgG, and EUROIMMUN® SARS-CoV-2 NeutraLISA assays, respectively) have been performed on individuals healed after SARS-CoV-2 infection. The correlation between each assay and the reference method has been explored through linear regression modeling, as well as through the calculation of Pearson's and Spearman's coefficients. Furthermore, the ability of serological tests to discriminate samples with high titers of neutralizing antibodies (>160) has been assessed by ROC curve analyses, Cohen's Kappa coefficient, and positive predictive agreement. The EUROIMMUN® NeutraLISA assay displayed the best correlation with PRNT results (Pearson and Spearman coefficients equal to 0.660 and 0.784, respectively), as well as the ROC curve with the highest accuracy, sensitivity, and specificity (0.857, 0.889, and 0.829, respectively).


Subject(s)
COVID-19 , SARS-CoV-2 , Antibodies, Neutralizing , Antibodies, Viral , COVID-19/diagnosis , COVID-19 Testing , Humans , Immunoglobulin G , Sensitivity and Specificity , Serologic Tests/methods
15.
Clin Lab ; 68(8)2022 Aug 01.
Article in English | MEDLINE | ID: covidwho-1994480

ABSTRACT

BACKGROUND: Identifying the distribution and pattern of specific aeroallergens in Sichuan, China, after the corona-virus disease (COVID-19) epidemic and to provide a basis for future prevention and clinical treatment. METHODS: Serological tests for 10 types of aeroallergens were performed on 10,036 participants attending the West China Second University Hospital from January 2020 to January 2021. SPSS23.0 was used to statistically analyze their specific immunoglobulin E (sIgE) grades in different genders, various age groups, and different diseases. RESULTS: Of the 10,036 participants, 4,578 (45.62%) were allergic to at least one allergen. House dust had the highest sensitization rate (2,974, 29.63%), followed by Dermatophagoides farina (2,717, 27.07%) and Dermatophagoides pteronyssinus (2,611, 26.02%). Male and female participants had no significant difference in overall sensitization distributions. The prevalence differences between 0 - 3, 4 - 6, 7 - 9, 10 - 12, 13 - 15, and over 16-year-old age groups were statistically significant (p < 0.05), and the highest incidence age for children to be sensitive to aeroallergens was 4 - 6 years, respectively. Sensitization to D. pteronyssinus, D. farina, house dust, dog epithelium, and Alternaria alternata was more common in patients with rhinitis and asthma compared with bronchitis. CONCLUSIONS: Aeroallergens are important causes of respiratory-related allergic diseases, and the characteristics of allergen sensitization discovered in this study could help with inhalant allergy disease prevention, diagnosis, and management in the post-epidemic era.


Subject(s)
Allergens , COVID-19 , Epidemics , Hypersensitivity , Adolescent , Allergens/analysis , COVID-19/epidemiology , Child , Child, Preschool , China/epidemiology , Dust , Female , Humans , Hypersensitivity/diagnosis , Hypersensitivity/epidemiology , Infant , Infant, Newborn , Male , Serologic Tests
16.
ScientificWorldJournal ; 2022: 7754329, 2022.
Article in English | MEDLINE | ID: covidwho-1993134

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection that causes coronavirus disease 2019 (COVID-19) is a disease with a high rate of transmission. Serological tests are important to perform surveys and to determine the immunological status of the population. Based on this, we evaluated three enzyme-linked immunoassays (ELISAs) using different antigens from SARS-CoV-2 in a cohort of 161 patients. The performance of the ELISA developed for immunoglobulin G (IgG) measurement against SARS-CoV-2 was evaluated based on sensitivity, specificity, and accuracy. We found specificities of 0.98, 0.98, and 0.99 and sensitivities of 0.99, 0.91, and 0.87 for the nucleocapsid (N) protein, spike protein, and receptor binding domain (RBD) fraction, respectively. The accuracy assessment indicated the N protein (accuracy = 0.98) as the antigen most likely to give a correct diagnosis. Overall, the antibody responses were present for all three proteins in subjects with confirmed SARS-CoV-2 infections, showing a similar pattern of antibody production for different antigens. In summary, these highly sensitive and specific ELISAs, with a more competitive price, appear to be a valid approach for the serodiagnosis of COVID-19.


Subject(s)
COVID-19 , SARS-CoV-2 , Antibodies, Viral , COVID-19/diagnosis , COVID-19/immunology , COVID-19 Testing , Enzyme-Linked Immunosorbent Assay , Humans , SARS-CoV-2/immunology , Sensitivity and Specificity , Serologic Tests , Spike Glycoprotein, Coronavirus
18.
J Infect Dis ; 226(10): 1721-1725, 2022 Nov 11.
Article in English | MEDLINE | ID: covidwho-1973170

ABSTRACT

To determine viral dynamics in Omicron breakthrough infections, we measured severe acute respiratory syndrome coronavirus 2 RNA in 206 double-vaccinated or boostered individuals. During the first 3 days following the onset of symptoms, viral loads were significantly higher (cycle threshold [Ct], 21.76) in vaccinated compared to boostered (Ct, 23.14) individuals (P = .029). However, by performing a longitudinal analysis on 32 individuals over 14 days, no difference in the viral load trajectory was observed between double-vaccinated and boostered patients. Our results indicate that booster immunization results in a reduction in detectable viral loads without significantly changing viral load dynamics over time.


Subject(s)
COVID-19 , Humans , SARS-CoV-2 , Viral Load , Serologic Tests , Antibodies, Viral
19.
PLoS One ; 17(7): e0271808, 2022.
Article in English | MEDLINE | ID: covidwho-1968870

ABSTRACT

PURPOSE: We aimed to elaborate whether cycle threshold (Ct) values differ significantly between wild type SARS-CoV-2 (wtV) and certain viral variants and how strong or weak a potential significant effect might be. METHODS: In a retrospective study, we investigated 1873 SARS-CoV-2 positive samples for the occurrence of viral marker mutations. Age, gender, clinical setting, days after onset of symptoms, and Ct values were recorded. Statistical analysis was carried out with special consideration of effect sizes. RESULTS: During the study period wtV was detected in 1013 samples (54%), while 845 (45%) patients carried the Alpha variant of concern (VOC), and 15 (1%) the Beta VOC. For further analysis, only wtV and the Alpha VOC were included. In a multi-factor ANOVA and post-hoc test with Bonferroni-correction for the age groups we found significant main-effects for Ct values of the viral variant (wtV mean 26.4 (SD 4.27); Alpha VOC mean 25.0 (SD 3.84); F (1,1850) = 55.841; p < .001) and the clinical setting (outpatients: mean 25.7 (SD 4.1); inpatients: mean 27.0 (SD 4.2); F (1,1850) = 8.520, p = .004). However, since the effect sizes were very small (eta squared for the Alpha VOC = .029 and the clinical setting = .004), there was only a slight trend towards higher viral loads of the Alpha VOC compared to wtV. CONCLUSIONS: In order to compare different variants of SARS-CoV-2 the calculation of effect sizes seems to be necessary. A combination of p-values as estimates of the existance of an effect and effect sizes as estimates of the magnitude of a potential effect may allow a better insight into transmission mechanisms of SARS-CoV-2.


Subject(s)
COVID-19 , SARS-CoV-2 , Humans , Retrospective Studies , SARS-CoV-2/genetics , Serologic Tests
20.
Sensors (Basel) ; 22(14)2022 Jul 21.
Article in English | MEDLINE | ID: covidwho-1957420

ABSTRACT

Innovative and highly performing smart voltammetric immunosensors for rapid and effective serological tests aimed at the determination of SARS-CoV-2 antibodies were developed and validated in human serum matrix. Two immunosensors were developed for the determination of immunoglobulins directed against either the nucleocapsid or the spike viral antigen proteins. The immunosensors were realized using disposable screen-printed electrodes modified with nanostructured materials for the immobilization of the antigens. Fast quantitative detection was achieved, with analysis duration being around 1 h. Signal readout was carried out through a smart, compact and battery-powered potentiostat, based on a Wi-Fi protocol and devised for the Internet of Things (IoT) paradigm. This device is used for the acquisition, storage and sharing of clinical data. Outstanding immunosensors' sensitivity, specificity and accuracy (100%) were assessed, according to the diagnostic guidelines for epidemiological data. The overall performance of the sensing devices, combined with the portability of the IoT-based device, enables their suitability as a high-throughput diagnostic tool. Both of the immunosensors were validated using clinical human serum specimens from SARS-CoV-2 infected patients, provided by IRCCS Ospedale San Raffaele.


Subject(s)
Biosensing Techniques , COVID-19 , Vaccines , Antibodies, Viral , Biosensing Techniques/methods , COVID-19/diagnosis , Humans , Immunoassay , Point-of-Care Systems , SARS-CoV-2 , Sensitivity and Specificity , Serologic Tests
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