Effectiveness of Coronavirus Disease 2019 Vaccines in Preventing Infection, Hospital Admission, and Death: A Historical Cohort Study Using Iranian Registration Data During Vaccination Program

  1. Alireza Mirahmadizadeh
  2. Alireza Heiran
  3. Kamran Bagheri Lankarani
  4. Mohammadreza Serati
  5. Mohammad Habibi
  6. Owrang Eilami
  7. Fatemeh Heiran
  8. Mohsen Moghadami

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Abstract

Background

There are some concerns about the effectiveness of the inactivated and vector-based vaccines against severe acute respiratory syndrome coronavirus 2 in real-world settings with the emergence of new mutations, especially variants of concern. Data derived from administrative repositories during mass vaccination campaigns or programs are of interest to study vaccine effectiveness.

Methods

Using 4-repository administrative data linkage, we conducted a historical cohort study on a target population of 1 882 148 inhabitants aged at least 18 years residing in southern Iran.

Results

We estimated a 71.9% [95% confidence interval [CI], 70.7%–73.1%], 81.5% [95% CI, 79.5%–83.4%], 67.5% [95% CI, 59.5%–75.6%], and 86.4% [95% CI, 84.1%–88.8%] hospital admission reduction for those who received the full vaccination schedule of BBIBP-CorV (Sinopharm), ChAdOx1-S/nCoV-19 vaccine (AZD1222, Oxford-AstraZeneca), rAd26-rAd5 (Gam-COVID-Vac, Sputnik V), and BIV1-CovIran (COVIran Barekat) vaccines, respectively. A high reduction in mortality (at least 85%) was observed in all age subgroups of the fully immunized population.

Conclusions

The pragmatic implementation of a vaccination plan including all available vaccine options in the Iranian population was associated with a significant reduction in coronavirus disease 2019 (COVID-19) detected infections as well as hospital admissions and deaths associated with COVID-19.

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  1. Version published to 10.1093/ofid/ofac177
  2. ScreenIT

    SciScore for 10.1101/2022.01.18.22269330: (What is this?)

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

    Table 1: Rigor

    EthicsField Sample Permit: 2-1- Study Design, Population and Data Repositories: As a potential spin-off of administrative data linkage, we conducted a historical cohort study on the individual data of a target population of 3,628,857 (out of 4,943,933) inhabitants aged at least 18 years residing in the regions under cover of the Shiraz University of Medical Sciences (SUMS), Fars province, Southern Iran, from the start of the vaccination program (February 09, 2021) to the end of follow-up (October 22, 2021).
    Sex as a biological variablenot detected.
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.
    Cell Line Authenticationnot detected.

    Table 2: Resources

    Experimental Models: Cell Lines
    SentencesResources
    The 4 vaccines studied against COVID-19 were [1] the BBIBP-CorV vaccine, which is a monovalent Vero cells vaccine composed of inactivated 19nCoV-CDC-Tan-HB02 (HB02) strain of SARS-CoV-2 virus antigens. [13]; [2] the ChAdOx1-S/nCoV-19 vaccine, which is a modified rAd vector (ChAdOx1), containing the full-length codon-optimized coding sequence of the spike protein of SARS-CoV-2 (ChAdOx1-S/nCoV-19), with a tissue plasminogen activator leader sequence [14]; [3] the rAd26-rAd5, which is a recombinant replication-deficient adenovirus (rAd)-based vaccine, containing rAd type 26 (rAd26) and rAd type 5 (rAd5) vectors that both of them carry the gene for SARS-CoV-2 full-length glycoprotein S (rAd26-S and rAd5-S) [2]; and [4] the BIV1-CovIran (COVIran Barekat), which is an inactivated whole-virus SARS-CoV-2 vaccine [15].
    Vero
    suggested: None

    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 findings in our study are subject to at least four limitations. First, vaccination status and outcome misclassifications might be plausible, comparing the vaccine efficacy studies, despite the high specificity of the COVID-19 vaccination status from our data repositories. Worth noting, we performed a number of data-recheck plans. Second, while our study covered a long follow-up period of 35 weeks, VE data with longer follow-up are warranted. Second, underestimation of actual SARS-CoV-2 infection among the study population might be happened due to the underuse of PCR tests for all suspected patients in the community. Third, noncomprehensive data entry – specifically, the COVID-19-related administrative data registries were not intended to collect the unvaccinated population data – for comorbidities and other confounding factors did not allow us to introduce these variables into the analysis. Fourth, due to lower numbers of vaccinated people with rAd26-rAd5 and BIV1-CovIran vaccines, VE values for these two vaccines might not be robust.

    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

    SciScore is an automated tool that is designed to assist expert reviewers by finding and presenting formulaic information scattered throughout a paper in a standard, easy to digest format. SciScore checks for the presence and correctness of RRIDs (research resource identifiers), and for rigor criteria such as sex and investigator blinding. For details on the theoretical underpinning of rigor criteria and the tools shown here, including references cited, please follow this link.

  3. Version published to 10.1101/2022.01.18.22269330v1 on medRxiv