ABSTRACT
The impact of the COVID-19 pandemic on large events has been substantial. In this work, an evaluation of the potential impact of international arrivals due to Expo 2020 in terms of potential COVID-19 infections from October 1st, 2021, until the end of April 2022 in the United Arab Emirates is presented. Our simulation results indicate that: (i) the vaccination status of the visitors appears to have a small impact on cases, this is expected as the small numbers of temporary visitors with respect to the total population contribute little to the herd immunity status; and (ii) the number of infected arrivals is the major factor of impact potentially causing a surge in cases countrywide with the subsequent hospitalisations and fatalities. These results indicate that the prevention of infected arrivals should take all precedence priority to mitigate the impact of international visitors with their vaccination status being of less relevance.
ABSTRACT
The world has faced the COVID-19 pandemic for over two years now, and it is time to revisit the lessons learned from lockdown measures for theoretical and practical epidemiological improvements. The interlink between these measures and the resulting change in mobility (a predictor of the disease transmission contact rate) is uncertain. We thus propose a new method for assessing the efficacy of various non-pharmaceutical interventions (NPI) and examine the aptness of incorporating mobility data for epidemiological modelling. Facebook mobility maps for the United Arab Emirates are used as input datasets from the first infection in the country to mid-Oct 2020. Dataset was limited to the pre-vaccination period as this paper focuses on assessing the different NPIs at an early epidemic stage when no vaccines are available and NPIs are the only way to reduce the reproduction number ( R 0 ). We developed a travel network density parameter ß t to provide an estimate of NPI impact on mobility patterns. Given the infection-fatality ratio and time lag (onset-to-death), a Bayesian probabilistic model is adapted to calculate the change in epidemic development with ß t . Results showed that the change in ß t clearly impacted R 0 . The three lockdowns strongly affected the growth of transmission rate and collectively reduced R 0 by 78% before the restrictions were eased. The model forecasted daily infections and deaths by 2% and 3% fractional errors. It also projected what-if scenarios for different implementation protocols of each NPI. The developed model can be applied to identify the most efficient NPIs for confronting new COVID-19 waves and the spread of variants, as well as for future pandemics.
ABSTRACT
BACKGROUND: This is a community-based, retrospective, observational study conducted to determine effectiveness of the BBIBP-CorV inactivated vaccine in the real-world setting against hospital admissions and death. STUDY DESIGN: Study participants were selected from 214,940 PCR-positive cases of COVID-19 reported to the Department of Health, Abu Dhabi Emirate, United Arab Emirates (UAE) between September 01, 2020 and May 1, 2021. Of these, 176,640 individuals were included in the study who were aged ≥ 15 years with confirmed COVID-19 positive status who had records linked to their vaccination status. Those with incomplete or missing records were excluded (n = 38,300). Study participants were divided into three groups depending upon their vaccination status: fully vaccinated (two doses), partially vaccinated (single dose), and non-vaccinated. Study outcomes included COVID-19-related admissions to hospital general and critical care wards and death. Vaccine effectiveness for each outcome was based on the incidence density per 1000 person-years. RESULTS: The fully-, partially- and non-vaccinated groups included 62,931, 21,768 and 91,941 individuals, respectively. Based on the incidence rate ratios, the vaccine effectiveness in fully vaccinated individuals was 80%, 92%, and 97% in preventing COVID-19-related hospital admissions, critical care admissions, and death, respectively, when compared to the non-vaccinated group. No protection was observed for critical and non-critical care hospital admissions for the partially vaccinated group, while some protection against death was apparent, although statistically insignificant. CONCLUSIONS: In a COVID-19 pandemic, use of the Sinopharm BBIBP-CorV inactivated vaccine is effective in preventing severe disease and death in a two-dose regimen. Lack of protection with the single dose may be explained by insufficient seroconversion and/or neutralizing antibody responses, behavioral factors (i.e., false sense of protection), and/or other biological factors (emergence of variants, possibility of reinfection, duration of vaccine protection, etc.).