Distinct Vaccine Efficacy Rates Among Health Care Workers During a COVID-19 Outbreak in Jordan

  1. Iyad Sultan
  2. Abdelghani Tbakhi
  3. Osama Abuatta
  4. Sawsan Mubarak
  5. Osama Alsmadi
  6. Adib Edilbi
  7. Ruba Al-Ani
  8. Manar Makhlouf
  9. Rawan Hajir
  10. Omar Khreisat
  11. Majeda A. Al-Ruzzieh
  12. Hikmat Abdelrazeq
  13. Asem Mansour

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Abstract

BACKGROUND

We aimed to assess the efficacy of 3 COVID-19 vaccines in a population of health care workers at a tertiary cancer center in Amman, Jordan.

METHODS

We evaluated the records of 2855 employees who were fully vaccinated with 1 of 3 different vaccines and those of 140 employees who were not vaccinated. We measured the number of SARS-CoV-2 infections that occurred at least 14 days after the second vaccine dose.

RESULTS

The 100-day cumulative incidence of PCR-confirmed SARS-CoV-2 infections was 19.3% ± 3.3% for unvaccinated employees and 1.7% ± 0.27% for fully vaccinated employees. The 100-day cumulative infection rates were 0.7% ± 0.22% in BNT162b2 vaccine recipients (n = 1714), 3.6% ± 0.77% in BBIBP-CorV recipients (n = 680), and 2.3% ± 0.73% in ChAdOx1 recipients (n = 456). We used Cox regression analyses to compare the risks of SARS-CoV-2 infection among the different vaccine recipient groups and found a significantly higher infection risk in BBIBP-CorV (hazard ratio [HR] = 2.9 ± 0.31) and ChAdOx1 recipients (HR = 3.0 ± 0.41) compared to BNT162b2 recipients ( P = .00039 and .0074, respectively). Vaccinated employees who had no previously confirmed SARS-CoV-2 infections were at a markedly higher risk for breakthrough infections than those who experienced prior infections (HR = 5.7 ± 0.73, P = .0178).

CONCLUSIONS

Our study offers a real-world example of differential vaccine efficacy among a high-risk population during a national outbreak. We also show the important synergism between a previous SARS-CoV-2 infection and vaccination.

Funding

None

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  1. ScreenIT

    SciScore for 10.1101/2022.01.15.22269356: (What is this?)

    Please note, not all rigor criteria are appropriate for all manuscripts.

    Table 1: Rigor

    EthicsIRB: After obtaining Institutional Review Board approval (KHCC-IRB#21KHCC110), we accessed deidentified employee records that were maintained by our Human Resources department, which included vaccination records and history of confirmed previous SARS-CoV-2 infections.
    Sex as a biological variablenot detected.
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.

    Table 2: Resources

    No key resources detected.

    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:
    The retrospective nature of our study introduced some obvious limitations. We cannot rule out some bias in selecting HCWs for specific types of vaccines. For example, our institutional campaign, which relied heavily on the BNT162b2 vaccine, was specifically directed towards our younger staff who were not prioritized to receive vaccines in the first few weeks of the national campaign. In conclusion, high rates of COVID-19 vaccination can be achieved among HCWs, even in the presence of high rates of hesitancy. The BNT162b2 vaccine was superior to the other vaccines available in Jordan, suggesting its value as a booster vaccine for HCWs who previously received other vaccine types. Mixing and matching vaccines appears to be effective and safe,16 but much more research is needed.

    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.

    About SciScore

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  2. Version published to 10.1101/2022.01.15.22269356 on medRxiv