Effectiveness of BNT162b2 and ChAdOx1 Vaccines against Symptomatic COVID-19 among Healthcare Workers in Kuwait: A Retrospective Cohort Study
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Abstract
Background: Estimating vaccine effectiveness (VE) against severe, acute respiratory syndrome coronavirus 2 (SARS-CoV-2) among healthcare workers (HCWs) is necessary to demonstrate protection from the disease. Between 24 December 2020 and 15 June 2021, we determined the factors associated with vaccine coverage and estimated VE against SARS-CoV-2 infection in HCWs at a secondary hospital in Kuwait. Methods: We extracted sociodemographic, occupational, SARS-CoV-2 infection, and vaccination data for eligible HCWs from the hospital records. Vaccine coverage percentages were cross-tabulated with the HCW factors. Cox regression was used to estimate hazard ratios in vaccinated versus unvaccinated. Results: 3246 HCWs were included in the analysis, of which 82.1% received at least one vaccine dose (50.4% only one dose of ChAdOx1, 3.3% only one dose of BNT162b2, and 28.3% two doses of BNT162b2). However, 17.9% of HCWs were unvaccinated. A significantly lower vaccination coverage was reported amongst female HCWs, younger age group (20–30 years), and administrative/executive staff. The adjusted VE of fully vaccinated HCWs was 94.5% (95% CI = 89.4–97.2%), while it was 75.4% (95% CI = 67.2–81.6%) and 91.4% (95% CI = 65.1–97.9%) in partially vaccinated for ChAdOx1 and BNT162b2, respectively. Conclusions: BNT162b2 and ChAdOx1 vaccines prevented most symptomatic infections in HCWs across age groups, nationalities, and occupations.
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SciScore for 10.1101/2021.07.25.21261083: (What is this?)
Please note, not all rigor criteria are appropriate for all manuscripts.
Table 1: Rigor
Ethics not detected. Sex as a biological variable These were: age group (20 -30, 31-40, 41 – 50, and >50), sex (male or female), nationality (Kuwaiti national and non-Kuwaiti resident), staff group (Administrative or Executive; Nursing or Health-care assistant; Doctor; Specialist Staff; Estates, Porters, or Security; and Pharmacist) and occupation settings (categorized into six groups: 1) office or laboratory, 2) hospital pharmacy, 3) outpatient including radiology, day ward, general practice, or renal dialysis unit, 4) inpatient ward, theatres, emergency department, maternity unit or labor ward, or ambulance, 5) intensive care, and 6) other (e.g., plaster and observational rooms). Randomization not … SciScore for 10.1101/2021.07.25.21261083: (What is this?)
Please note, not all rigor criteria are appropriate for all manuscripts.
Table 1: Rigor
Ethics not detected. Sex as a biological variable These were: age group (20 -30, 31-40, 41 – 50, and >50), sex (male or female), nationality (Kuwaiti national and non-Kuwaiti resident), staff group (Administrative or Executive; Nursing or Health-care assistant; Doctor; Specialist Staff; Estates, Porters, or Security; and Pharmacist) and occupation settings (categorized into six groups: 1) office or laboratory, 2) hospital pharmacy, 3) outpatient including radiology, day ward, general practice, or renal dialysis unit, 4) inpatient ward, theatres, emergency department, maternity unit or labor ward, or ambulance, 5) intensive care, and 6) other (e.g., plaster and observational rooms). Randomization not detected. Blinding not detected. Power Analysis not detected. Table 2: Resources
Software and Algorithms Sentences Resources All analyses were conducted in STATA statistical software. STATAsuggested: (Stata, RRID:SCR_012763)Results from OddPub: We did not detect open data. We also did not detect open code. Researchers are encouraged to share open data when possible (see Nature blog).
Results from LimitationRecognizer: We detected the following sentences addressing limitations in the study:This study has several limitations. First, the study was based on one public secondary hospital and might not be generalizable to HCWs in other public hospitals in Kuwait. However, this hospital is one of the major healthcare facilities in Kuwait and serves over a quarter of the country’s population. Second, the identification of HCWs SARS-CoV-2 PCR-confirmed infections was based on passive reporting to the hospital management due to lack of active laboratory surveillance. However, it was/is required by all HCWs to report PCR-confirmed infections to their upper management within each hospital’s department. Furthermore, underreporting PCR-confirmed infections might underestimate the ‘actual’ number of infections regardless of vaccination status; if this disproportionately impacted those who were unvaccinated compared to those who were vaccinated, this could overestimate vaccine effectiveness. Third, vaccine effectiveness estimates for partial immunity (≥ 14 days after BNT162b2 first dose through receipt of second dose) had wide confidence intervals which likely due to the low number of PCR-confirmed infections reported. In conclusion, vaccine effectiveness of both BNT162b2 and ChAdOx1 COVID-19 vaccines in HCW under ‘real-world’ conditions demonstrated that vaccine is effective in preventing most symptomatic infection across age groups, nationalities, occupation setting, and staff groups. A significant proportion (17.9%) of HCWs were unvaccinated despite the vaccine accessibili...
Results from TrialIdentifier: No clinical trial numbers were referenced.
Results from Barzooka: We did not find any issues relating to the usage of bar graphs.
Results from JetFighter: We did not find any issues relating to colormaps.
Results from rtransparent:- Thank you for including a conflict of interest statement. Authors are encouraged to include this statement when submitting to a journal.
- Thank you for including a funding statement. Authors are encouraged to include this statement when submitting to a journal.
- No protocol registration statement was detected.
Results from scite Reference Check: We found no unreliable references.
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