An analysis of antibody response following the second dose of CoronaVac and humoral response after booster dose with BNT162b2 or CoronaVac among healthcare workers in Turkey.

Limited data are available on the short- to midterm levels of antibodies to the CoronaVac vaccine and quantitative change in humoral response after homologous or heterologous booster doses. In this prospective cohort study, we evaluated the anti-receptor-binding domain (RBD) immunoglobulin G (IgG) levels after two doses of CoronaVac and heterologous/homologous booster administration among healthcare workers in a university hospital in Turkey. Quantitative anti-RBD IgG antibody levels were measured at first and fourth months in 560 healthcare workers who had completed two doses of CoronaVac vaccine, and within 2 months after the third dose of CoronaVac or BNT162b2. Participants were asked to complete a questionnaire during the first blood draw. The seropositivity rate was 98.9% and 89.1%, and the median antibody level was 469.2 AU/ml and 166.5 AU/ml at first and fourth month, respectively. In the fourth month, a mean reduction of 61.4% ± 20% in antibody levels was observed in 79.8% of the participants. The presence of chronic disease (odds ratio [OR]: 1.76, 95% confidence interval [CI]: 1.15-2.69) and being in the 36-50 age group (OR: 2.11, 95% CI: 1.39-3.19) were identified as independent predictors for low antibody response. The antibody level increased 104.8-fold (median: 17 609.4 vs. 168 AU/ml) and 8.7-fold (median: 1237.9 vs. 141.4 AU/ml) in the participants who received BNT162b2 and CoronaVac, respectively. During the follow-up, 25 healthcare workers (4.5%) were infected with severe acute respiratory syndrome coronavirus 2. Considering the waning immunity and circulating variants, a single booster dose of messenger RNA vaccine seems reasonable after the inactivated vaccine especially in risk groups.

Tracking SARS-CoV-2, Ízmir, Turkey: Journal of Pediatric Infection

In more severe cases, pneumonia, severe acute respiratory tract infection, kidney failure may develop and the disease can result in death (4). In our study, it was planned to evaluate pediatric patients who presented to our hospital with findings of respiratory tract infection retrospectively, to scan SARS-CoV-2 RNA in the respiratory tract specimens in our archive and to conduct an investigation by sequence analysis in case positivity was detected. Materials and Methods 886 respiratory tract specimens that had been sent to the Central Laboratory from the pediatric inpatients and outpatients of Dokuz Eylul University Faculty of Medicine (DEU) Hospital between October 1, 2019 and March 31, 2020 for the investigation of the causes for viral respiratory tract infection and that had been kept at -70°C were included in the study. Viral target region in the kit is the SARS-CoV-2 RNA-dependent RNA polymerase (RbRp) gene fragment, and human ribonuclease P (RNase P) gene fragment was used as internal control.

Evaluation of COVID-19 antibody response with using three different tests.

BACKGROUND AND OBJECTIVES: In this study, the performance of three different commercial antibody assays for COVID-19 was examined and parameters affecting the antibody response were investigated. The correlation of patients' chest CT results, procalcitonin, CRP, and D-dimer levels with the antibody response were retrospectively evaluated. MATERIALS AND METHODS: COVID-19 antibodies were detected by three commercially available assays in each patient. Two of the assays were rapid immunochromatographic tests and - one was an ELISA-based IgG assay. SARS-CoV-2 RNA was tested by "COVID-19 RT-qPCR Detection Kit" using nasopharyngeal swab samples. The results of antibody tests were compared with each other, RT-qPCR, Biochemical parameters and chest CT findings. RESULTS: RT-qPCR was positive in 46.6% (41/88) of the evaluated patients among which 77.3% (68/88) were healthcare workers. Seventeen (41.4%) of viral RNA positive patients had a positive antibody result with at least two assays. Both of the rapid immunochromatographic tests had identical sensitivity of 36.6% and specificity of 100%, compared to RT-qPCR assay; while the sensitivity of the ELISA based Euroimmune test was 43.9%, and the specificity was 95.7%. The sensitivity and specificity of the immunochromatographic tests were 75% and 100% respectively, compared to ELISA test result. There was a correlation between antibody positivity and old age and male gender. The presence of typical chest CT findings increased the antibody positivity 13.62 times. Antibody positivity was also increased with the decrease in Ct value of the PCR assay. There was no significant relationship between the biochemical parameters (CRP, D-dimer and procalcitonin values) and the antibody or RT-qPCR results. CONCLUSION: There was a correlation between antibody response and male gender, older age, presence of symptoms, typical chest CT findings and low PCR-Ct value.

Evaluation of COVID-19 antibody response with using three different tests

Background and Objectives: In this study, the performance of three different commercial antibody assays for COVID-19 was examined and parameters affecting the antibody response were investigated. The correlation of patients' chest CT results, procalcitonin, CRP, and D-dimer levels with the antibody response were retrospectively evaluated. Materials and Methods: COVID-19 antibodies were detected by three commercially available assays in each patient. Two of the assays were rapid immunochromatographic tests and - one was an ELISA-based IgG assay. SARS-CoV-2 RNA was tested by "COVID-19 RT-qPCR Detection Kit" using nasopharyngeal swab samples. The results of antibody tests were compared with each other, RT-qPCR, Biochemical parameters and chest CT findings. Results: RT-qPCR was positive in 46.6% (41/88) of the evaluated patients among which 77.3% (68/88) were healthcare workers. Seventeen (41.4%) of viral RNA positive patients had a positive antibody result with at least two assays. Both of the rapid immunochromatographic tests had identical sensitivity of 36.6% and specificity of 100%, compared to RT-qPCR assay;while the sensitivity of the ELISA based Euroimmune test was 43.9%, and the specificity was 95.7%. The sensitivity and specificity of the immunochromatographic tests were 75% and 100% respectively, compared to ELISA test result. There was a correlation between antibody positivity and old age and male gender. The presence of typical chest CT findings increased the antibody positivity 13.62 times. Antibody positivity was also increased with the decrease in Ct value of the PCR assay. There was no significant relationship between the biochemical parameters (CRP, D-dimer and procalcitonin values) and the antibody or RT-qPCR results. Conclusion: There was a correlation between antibody response and male gender, older age, presence of symptoms, typical chest CT findings and low PCR-Ct value. [ABSTRACT FROM AUTHOR] Copyright of Iranian Journal of Microbiology is the property of Tehran University of Medical Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Clinical and radiological diagnosis of non-SARS-CoV-2 viruses in the era of COVID-19 pandemic.

Following the announcement of the first coronavirus disease 2019 (COVID-19) case on 11 March 2020 in Turkey, we aimed to report the coinfection rates, and the clinical, laboratory, radiological distinctive features of viral pneumonia caused by viruses other than severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). A cross-sectional study was conducted between 18 and 31 March 2020. COVID-19 suspected cases admitted to pandemic policlinic, who had nasopharyngeal swab specimens tested for both SARS-CoV-2 and other respiratory viral pathogens, were included. Among 112 patients, SARS-CoV-2 was detected in 34 patients (30%). Among the non-SARS-CoV-2 viruses (n = 25, 22%), metapneumovirus (n = 10) was the most frequent agent. There were two coinfections with SARS-CoV-2. Sputum was less in the SARS-CoV-2 group (P = .003). The leukocyte, lymphocyte, and thrombocyte count and C-reactive protein levels were the lowest in the SARS-CoV-2 group (P < .001, P = .04, P < .001, P = .007, respectively). Peripheral involvement (80% vs 20%; P ≤ .001), pure ground-glass opacity (65% vs 33%; P = .04), apicobasal gradient (60% vs 40%; P = .08), involvement of greater than or equal to three lobes (80% vs 40%; odds ratio: 6.0; 95% confidence interval: 1.33-27.05; P = .02), and consolidation with accompanying ground-glass opacity (4% vs 33%; P = .031) were more common in SARS-CoV-2 group. Some clinical, laboratory, and radiological findings may help in the differential diagnosis of non-SARS-CoV-2 viruses from COVID-19. However, coinfections may occur, and a non-SARS-CoV-2 pathogen positivity does not exclude accompanying COVID-19.