ABSTRACT
Introduction: Collection media of clinical samples with the capacity to denature viruses reduce the risk of contagion during transportation and processing. Objective(s): To use the nucleic acids transport media (NATM) in nasopharyngeal swab samples collected for the diagnosis of SARS-CoV-2. Method(s): An experimental study was conducted to demonstrate the medium capacity to inactivate viral infectivity. Zika virus (ZIKV), of biosafety level 2, was used as an enveloped virus model. The clinical performance of the NATM for the diagnosis of SARS-CoV-2 was evaluated. A ZIKV strain propagated in the Vero cell line was used and, prior to cells infection, ZIKV was in contact at different intervals (2;15, and 30 min) with pure NATM;subsequently, serial dilutions (10-1-10-4) were performed. Viral inactivation was evaluated by RT-PCR in the supernatant and the collected cells when the propagation period was completed. CITOSWAB VTM was used as reference to estimate the clinical performance of the NATM in 30 nasopharyngeal swabs collected for the diagnosis of SARS-CoV-2 infection. Result(s): ZIKV remained infectious at inoculum dilutions of >= 10-2, regardless of contact time. Clinical specificity and sensitivity of the NATM for the diagnosis of SARS-CoV-2 were 100%, respectively. Conclusion(s): Results suggest that ZIKV positive clinical samples at dilutions <= 10-1 of the NATM can be safely handled, which could potentially be applied to the molecular diagnosis of SARS-CoV-2. Copyright © 2022, Editorial Ciencias Medicas. All rights reserved.
ABSTRACT
Introduction: This paper shows the results obtained in the validation of in vitro serological assays to detect IgM, IgG antibodies, and total antibodies against SARS-CoV-2 UMELISA SARS-CoV-2 IgM, UMELISA ANTI-SARS-CoV-2 and UMELISA SARS-CoV-2 IgG developed by the Immunoassay Center.
ABSTRACT
Introduction: This paper shows the results obtained in the validation of in vitro serological assays to detect IgM, IgG antibodies, and total antibodies against SARS-CoV-2 UMELISA SARS-CoV-2 IgM, UMELISA ANTI-SARS-CoV-2 and UMELISA SARS-CoV-2 IgG developed by the Immunoassay Center. Methods: Panels of serum samples from negative and COVID-19 confirmed patients were used to determine the analytical performance of each assay. Results: UMELISA SARS-CoV-2 IgM, UMELISA ANTI-SARS-CoV-2 and UMELISA SARS-CoV-2 IgG assays demonstrated 100% clinical specificity for all assays;and 100% analytical specificity for the first two assays, and 93.1% for the last one. Clinical sensitivity was 64.3%, 80.8% and 97.5%, respectively. The positive predictive value was 100% in all assays, while the negative predictive value ranged from 83.3% to 95.2%. Concordance varied from 92.4% to 96.9%, and kappa index in every assay was very good. Assays sensitivity increased to 82.7%, 96.5% and 100 %, respectively for serum samples collected more than 14 days after onset of the symptoms. Conclusions: The assays demonstrated high sensitivity and specificity, which allows us to have Cuban technology-based tools for serological, epidemiological surveillance, and other types of studies, including those related to vaccines on a platform with wide national distribution. © 2022, Editorial Ciencias Medicas. All rights reserved.
ABSTRACT
Background: We provide care for the rural, low-income, and underserved population of Oroville. The community has a vaccination rate of 50% and booster rate of over 20% in the 3rd year of the ongoing global SARS-CoV-2 pandemic in 2022. During this period, a subset of our cancer patients benefited from the use of immune checkpoint inhibitors. Methods: This is a cross-sectional observational study of the effectiveness of a mRNA-based vaccine in medical care workers compared to patients with systemic malignancies treated with immunomodulation of PD-1 and CTLA-4 inhibitors. The study was approved by the hospital IRB. We evaluated the total anti-Spike protein antibody titer using a commercial semi-quantitative assay, Labcorp Test #164090. All subjects received 3 doses of the mRNA vaccine. We excluded anyone who was administered therapeutic monoclonal antibodies (mAb) or had a recent infection within 120 days. Results: Subjects with systemic malignancies were significantly older, p = 0.0001 by t-test: median age: 76, range: 64-82, compared to health care workers: median age: 52, range: 21-75. Accrual had to be prematurely stopped upon the arrival of Omicron wave in the community. Out of the seven subjects treated with immunomodulation, six received nivolumab, including two in combination with ipilimumab. One subject received pembrolizumab. Six of the subjects had metastatic disease: one was treated adjuvantly for locally advanced esophageal adenocarcinoma. The rest had NSCLC and one case of urothelioma. We divided the groups to those who had the highest titer of antibody versus everybody else and found a similar distribution in both groups using the Chi2 test. The vast majority of the healthcare workers, 24/27 or 89%, had above the upper limit antibody titer. Patients with systemic malignancy, 5/7 or 71%, had above the upper limit antibody titer p = N.S. Conclusions: Three doses of the mRNA vaccine provided high titers irrespective of frailty or age. We hypothesize that immunomodulation could favorably affect vaccination response.
ABSTRACT
Introduction: In late 2019, a new coronavirus was detected in China causing an acute respiratory illness known as COVID-2019. Objective. Evaluate seven commercial systems for the rapid detection of antibodies to determine their sensitivity, specificity and robustness in our conditions to be used by the National Health System. Methods: Seven systems were evaluated for the detection of IgM/IgG antibodies. Evaluation panel with samples from negative individuals, sera from other pathologies prior to the pandemic and from positive patients with the disease were conformed. Results: General sensitivity figures range between 25 and 88%, with the Realy Tech and Deep Blue systems showed the best results. The specificity for both was 100%. The IgM positive rate according to Realy Tech or Deep Blue increased to 94.1 or 81.8% in the late stage of the disease. Conclusions: Realy Tech and Deep Blue systems detected IgM/IgG in serum and in whole blood with adequate sensitivity and specificity. Cross-reactivity does not seem to be a problem. Serology in the case of COVID-19 cannot be used as a diagnostic but it allows epidemiological surveillance to know the immune status of populations. It’s essential to analyze the immune response against the infection to carry out epidemiological characterization and potentially inform individual risk of future disease and the study of potential vaccines. © 2021, Editorial Ciencias Medicas. All rights reserved.