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BACKGROUND: The coronavirus disease 2019 (COVID-2019) causes the severe contagious acute respiratory syndrome. Therefore, massive vaccination campaign is mandatory to control the spread. Sputnik COVID-19 vaccines induce immunity through different mechanisms involving antibody response that bind to the spike protein to neutralize the viral entry into the cells. AIM: This study aims to compare the titers of specific antibodies in the pre- and post-vaccination sera in the vaccinated Egyptian population to evaluate the efficacy of the sputnik vaccine. METHODS: Samples were collected from 205 adult volunteers receiving the Sputnik vaccine in the Reference Laboratory of Egyptian University Hospitals. Samples were collected before vaccination and within 1, 2, or 3 months after receiving two doses of Sputnik SARS-CoV-2 vaccines from August to October 2021, serum samples collected were tested by quantitative chemiluminescent immunoassay using (Mindray CL-960i chemiluminescence analyzer, India) at the Reference laboratory of Egyptian University Hospitals for neutralizing antibodies, anti-spike antibodies, and total antibody levels before and after vaccination. RESULTS: The results of the 205 paired samples illustrated that there was a statistically significant difference between pre- and post-vaccination antibody levels with a p-value of (< 0.001) indicating that the vaccine produced significantly high levels of antibodies. CONCLUSION: COVID-19 Sputnik vaccines induce immunity through an antibody response that binds to the virus to neutralize its entry into cells. Our study showed a significant increase in the measured post-vaccination levels of the three antibodies among the enrolled volunteers compared to the basal pre-vaccination level and thus sputnik vaccine protects against SARS-CoV-2 infections.

BACKGROUND: Detection of positive 2019-nCoV nucleic acids by real-time reverse transcriptase-polymerase chain reaction (rRT-PCR)-based assays performed on the upper and lower respiratory samples remains the gold standard for the diagnosis of COVID-19. However, antigen-detecting rapid diagnostic tests can offer a faster (15–30 min) and less expensive way to diagnose active severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection than nucleic acid amplification tests. AIM: Hence, the present study aimed to compare and evaluate the results of different SARS-CoV-2 rapid point-of-care antigen tests with SARS-CoV-2 PCR as a reference method. METHODS: Sixty-five nasopharyngeal swab specimens were collected from attendees of the Reference Laboratory of Egyptian university hospitals. The samples were placed in viral transport medium for RNA extraction. The remaining part of the suspension was stored at −70°C until use for COVID-19 antigen testing. All samples were processed for the COVID-19 Ag rapid test and RT-PCR simultaneously. RESULTS: RT-PCR assay revealed 46 (70.8%) positive samples and 19 (29.2%) negative samples for COVID-19. All eight rapid antigen assays indicated specificity and positive predictive value of 100% each. As for the other parameters, the sensitivity, negative predictive value (NPV), and accuracy ranged from 43.8 to 93.8, 33.3 to 90, and 60 to 96, respectively. Biozak exhibited the best performance with the highest sensitivities 91.3, 81.8, and 93.75, respectively, while Viro and Standard Q were the worst among the tested kits with sensitivity, NPV, and accuracy of 50, 33.3, and 60 each. Regarding the relationship between the viral load of COVID-19 detected by RT-PCR and the results of the eight rapid antigen tests (RAT), we deduced that the higher the viral load, the better the sensitivity observed. CONCLUSION: The RATs used, in our study, exhibited heterogeneous diagnostic performance, where some of them showed very promising results in comparison to the reference RT-PCR assay.

BACKGROUND: Readily available, accurate, and rapid diagnostic technologies are of high priority to contain emerging and re-emerging pandemics and to properly allocate personal protective equipment usage and preventing nosocomial spread with subsequent community transmission. Detection of positive 2019-nCoV nucleic acids by real-time reverse transcriptase-polymerase chain reaction (rRT-PCR)-based assays remains the gold standard for COVID-19 diagnostics. However, these assays take an average over 3–5 h to generate results and the PCR tests require certified laboratories, expensive equipment, and trained technicians to operate. Therefore, there is an urgent need for rapid point of care molecular tests that can be readily used in a healthcare setting that generates reliable results within few hours. Those tests should provide reliable results in the setting to facilitate the diagnosis and rapid decision-making. AIM: The present study aimed to evaluate the diagnostic performance of Abbott ID NOW SARS-CoV-2 compared to two gold standard assays (Allplex 2019- nCoV and VIASURE SARS-CoV-2) and to detect the relation between viral load and the sensitivity of ID NOW SARS-CoV-2 assay. METHODS: A total of 86 and 42 nasopharyngeal swabs collected from patients attending the Reference Laboratory of Egyptian University Hospitals during the period from January 2022 to May 2022, were tested by our reference methods of RT-PCR for COVID-19 detection; VIASURE kit and Allplex kits, respectively. Corresponding dry nasal swabs were collected from the same patients for ID NOW SARS-CoV-2 ribonucleic acid (RNA) detection assay. RESULTS: As regards the results of the 86 nasopharyngeal swabs tested by both VIASURE kit and ID NOW, there was a good agreement between both methods (95%) (kappa = 0.924), where the ID NOW method was not able to detect three COVID-19-positive samples (3/86, 5.1%). ID NOW exhibited specificity and sensitivity of 100% and 94.9%, respectively. As for comparing results of ID NOW with Allplex kit, the results of the 42 nasopharyngeal swabs tested by both tests revealed good agreement between both methods (kappa = 0.908). In comparison with Allplex kit, ID NOW exhibited specificity and sensitivity of 90% and 100%, respectively. Regarding the relation between the viral load detected by VIASURE kit and results of the ID NOW test, we found that ID NOW showed a sensitivity of 82.35% in samples with low viral load (CT > 30), while for samples with intermediate (CT: 20–30) and high (CT < 20) viral loads, sensitivity was 100%. CONCLUSION: ID NOW assay in our study exhibited a high diagnostic performance when evaluated with the gold standard RT-PCR methods. Our study further substantiates the high sensitivity of ID NOW in the presence of intermediate and high viral loads detected by molecular RT-PCR SARS-CoV-2 testing. Its analytical performances, combined with the very short 13 min reactional time and the friendly device-guided handling procedure, constitute an additional advantage of ID NOW COVID-19 for setting up a rapid diagnosis within the clinical laboratories and for timely identification of outbreaks allowing for aggressive contact tracing and containment.

BACKGROUND: To date, the molecular assay is the gold-standard method for coronavirus disease 2019 (COVID-19) diagnosis. However, they are expensive and complex. There is a pressing necessity for developing other effective diagnostics for severe acute respiratory syndrome coronavirus (SARS-CoV)-2 patients. Therefore, serological detection of antibodies against SARS-CoV-2 might provide a good alternative. AIM: We aimed to compare and evaluate seven rapid diagnostic tests with Mindray chemiluminescent automated immunoassay as a reference method for SARS-CoV-2 antibodies detection. METHODS: This study included the serum of a total of 49 attendees to the Reference Laboratory of Egyptian university hospitals during the period from April 2021 to May 2021. Anti-COVID-19 antibodies detection in serum samples was performed by Mindray fully automated system as our reference method and seven rapid antibody tests;Wondfo, Vazyme, Dynamiker, Panbio, Artron Maccura and Roche. RESULTS: The chemiluminescent assay revealed 30 (61.2%) positive samples and 19 (38.8%) negative samples for COVID-19 immunoglobulin (Ig) G. For COVID-19 IgM, 11 (22.4%) samples were positive and 38 (77.6%) samples were negative. Anti-SARS-CoV-2 antibodies were not detected in any of the PCR-negative individuals. The best diagnostic performance was demonstrated by Roche IgG and IgM, and Vazyme IgG and IgM antibody tests followed by Panbio. For Roche, the sensitivity and specificity for IgG and IgM were (83.3% and 89.5%) and (72.7% and 81.6%), respectively. Vazyme showed sensitivity and specificity for IgG and IgM were (77.8% and 85.7%) and (75% and 91.7%), respectively. Regards Panbio, the sensitivity and specificity for IgG and IgM were (63.6% and 87.5%) and (50% and 86.7%) respectively. Cohen’s Kappa values revealed a substantial agreement for Roche IgG, Vazyme IgG and IgM of (0.7076, 0.6250, 0.6667) respectively. The worst agreement was reported for Maccura IgG, Wondfo, and Dynamiker IgM with Cohen’s Kappa values of (0.2508, 0.1893, and 0.0313), respectively. CONCLUSIONS: Rapid tests in our study exhibited heterogeneous diagnostic performances. Roche, Vazyme, and Panbio antibody tests showed promising results in concordance with our reference method with the best-reported results. On the other hand, the other tests were inferior and failed in providing valid and reliable results. Further studies are necessary to determine the practicality of these tests in different settings and communities.