Impact of the Sinopharm's BBIBP-CorV vaccine in preventing hospital admissions and death in infected vaccinees: Results from a retrospective study in the emirate of Abu Dhabi, United Arab Emirates (UAE)

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.).

Keywords: COVID-19; Inactivated viral vaccine; Real-world vaccine effectiveness study; SARS-CoV-2; Sinopharm BBIBP-CorV vaccine; United Arab Emirates (UAE).

Graphical abstract

Fig. 1

Data collection plan. Flow chart of the data collection plan for the study.

Fig. 2

Study design and participant numbers. The study participants were divided into three groups (fully vaccinated with two doses of vaccine, partially vaccinated with one does of the vaccine, and unvaccinated) and followed for admission to the general hospital ward, critical care units, or death. See text for details.

Fig. 3

Effectiveness of the Sinopharm BBIBP-CorV vaccine. Graphs revealing the cumulative risk of: A) admission into a hospital general ward, B) admission into critical care units, and C) death. The number of patients in each category are listed below the graphs.