Risk of hospitalization and vaccine effectiveness among COVID-19 patients in the UAE during the Delta and Omicron outbreaks

Abstract

IntroductionA rapid increase in COVID-19 cases due to the spread of the Delta and Omicron variants in vaccinated populations has raised concerns about the hospitalization risk associated with, and the effectiveness of, COVID-19 vaccines.MethodThis case–control study aims to determine the hospitalization risk associated with the inactivated BBIBP-CorV (Sinopharm) and mRNA BNT162b2 (Pfizer–BionTech) vaccines, and their effectiveness reducing the rate of hospital admission between 28 May 2021 and 13 January 2022, during the Delta and Omicron outbreaks. The estimation of vaccine effectiveness of 4,618 samples was based on the number of patients hospitalized at different vaccination statuses, adjusted for confounding variables.ResultsHospitalization risk increases in patients affected with the Omicron variant if patients are aged ≤ 18 years (OR 6.41, 95% CI 2.90 to 14.17; p < 0.001), and in patients affected with the Delta variant if they are aged > 45 years (OR 3.41, 95% CI 2.21 to 5.50; p < 0.001). Vaccine effectiveness reducing the rate of hospital admission for fully vaccinated participants infected with the Delta and Omicron variants was similar for both the BBIBP-CorV (94%, 95% CI 90% to 97%; 90%, 95% CI 74% to 96%) and BNT162b2 vaccines (95%, 95% CI 61% to 99.3%; 94%, 95% CI 53% to 99%), respectively.DiscussionThe BBIBP-CorV and BNT162b2 vaccines utilized in the UAE vaccination program were highly effective in reducing the rate of COVID-19-related hospitalization during the Delta and Omicron outbreaks, and further effort must be taken to achieve high vaccine coverage rates in children and adolescents in the global context to reduce the hospitalization risk associated with COVID-19 on an international scale.

The impact of comorbidity status in COVID-19 vaccines effectiveness before and after SARS-CoV-2 omicron variant in northeastern Mexico: a retrospective multi-hospital study

“…The association of COVID-19 infection, hospitalization and death with vaccination status was performed by stepwise multivariate logistic ordinal regression. From this analysis, different models were performed to calculate odds ratios (OR) and 95% confidence intervals (CI) for each outcome of interest and from these OR (25,(66)(67)(68)(69)(70)(71).…”

“…Three main outcomes were analyzed, (a) Infection (yes, no) (b) Hospitalization (yes, no), and (c) Death secondary to COVID-19 complications (yes, no). VE was calculated with the following formula: VE = (1 − OR) × 100% this method is widely used to calculate vaccine effectiveness (25,(66)(67)(68)(69)(70)(71).…”

Clinical Evaluation of Omicron Subvariant Ba. 2- A Hospital Based Study

“…The possibility of being admitted to a hospital from an emergency department. Omicron (Hazard Ratio 0.33, 95 percent CI: 0.30 to 0.33) was about one-third of Delta (Hazard Ratio 0.33, 95 percent CI: 0.30 =-098721 [8] Study from African population showed that in the early stages of the fourth wave in South Africa, a different pattern of features and outcomes was found in patients hospitalized with COVID-19 compared to earlier waves, with younger patients having fewer comorbidities, fewer hospitalizations, and lower respiratory rates. [2] COVID-19 immunization, including a booster dose, was linked to a decreased risk of intensive care unit admission in people hospitalized with SARS-CoV-2 infection during Omicron predominance.…”

Vaccine Effectiveness against SARS-CoV-2 Infection during the Circulation of Alpha, Delta, or Omicron Variants: A Retrospective Cohort Study in a Tertiary Hospital in Serbia

“…At the end of 2020, after numerous experimental studies [ 1 , 2 , 3 , 4 ], different types of vaccines against the coronavirus disease of 2019 (COVID-19) became available in the wider population, as one of the most significant and effective measures to prevent COVID-19. Then, real-life observational studies showed the protective effect of vaccines in different parts of the world and in different populations [ 5 , 6 , 7 , 8 , 9 ]. The widespread uptake of COVID-19 vaccines has become the most powerful weapon in controlling the COVID-19 pandemic.…”