ABSTRACT
Background: Vaccination against SARS-CoV-2 is a potent preventive tool against Covid-19. However, response to vaccination vary depending on comorbidities. This study evaluates clinical and immunological factors affecting humoral response of End-Stage Renal Disease(ESRD) patients to BNT162b2 Vaccine. Method(s): Humoral immunity was evaluated in 54 ESRD patients, by serum levels of anti-receptor-binding-domain (RBD) and neutralizing antibodies (Nab), measured by CLIA, 30 (T1), 60 (T2) and 120 (T3) days, after the second vaccine dose. Results were correlated to baseline patients' T and B-lymphocyte subpopulations as determined by flow cytometry. Result(s): Proportion of seroconverted patients based on Nab titer was diminished from 83.3%(T1) to 53.7%(T3), in three months. Age was negatively correlated to Nab at T1 and T2 (T1:R=-0.334, p=0.027, T2:R=-0.344, p=0.022). Patients on hemodiafiltration had higher Nab titers at T3. Presence of diabetes was associated with lower response rate, as 9/11 diabetics compared to 16/43 non-diabetics lost seroconversion at T3. Univariate analysis revealed a strong positive correlation of naive CD4 T-lymphocyte population with RBD at T1(R2=0.199, p=0.015) and with Nab titer at T3(R2=0.645, p<0.001), while no association was shown with naive CD8 T-lymphocytes. Nab titers at T3 were significantly correlated with late differentiated CD4 T-lymphocytes(R2=0.56, p<0.001) and EMRA CD8 T-lymphocytes(R2=0.156, p=0.017). Finally, RBD levels had a significant positive correlation with naive, and negative with memory B-lymphocyte count at T3(R2=0.147, p=0.031, R2=0.159, p=0.039, respectively). Conclusion(s): Age, diabetes mellitus and hemodialysis prescription have a strong impact to response to vaccination. T and B-lymphocytes phenotype are major determinants of humoral response potency to COVID vaccination with BNT162b2, in ESRD patients.
ABSTRACT
The COVID-19 pandemic has rapidly affected humanity’s habits, forcing governments to obtain special measures to ensure world health. The imposition of the social distance measure has raised several questions about the future of tourism. Thus, smart cities (SC) are at the focal point, while their technological capabilities being re-examined for their effectiveness during the pandemic crisis. So far, several solutions have been proposed by the tech giants, states, and the European Union (EU), using Information Communication Technology (ICT) and solutions supported by Bluetooth, Radio Frequency Identification (RFID), Near Field Communication (NFC), Internet of Things (IoT), as well as Artificial Intelligence (AI). This conceptual paper examines the use of an access point for the tourism of the COVID-19 era, implicated for visitors, marketers, and city authorities-administration, using the NFC technology, or solely a digital ticket. The visitor-user will be informed by an app concerning the social distancing, while at the same time, the user will have the possibility of Transmedia (TM) personalized experience. © 2021, The Author(s), under exclusive license to Springer Nature Switzerland AG.