Performance of vaccination with CoronaVac in a cohort of healthcare workers (HCW) - preliminary report

  1. Elizabeth de Faria
  2. Ana Rubia Guedes
  3. Maura S. Oliveira
  4. Moacyr Vergara de Godoy Moreira
  5. Fernando Liebhart Maia
  6. Antonio dos Santos Barboza
  7. Mariana Deckers Leme
  8. Leila S. Harima Letaif
  9. Anna Miethke-Morais
  10. Eloisa Bonfá
  11. Aluisio C. Segurado
  12. Francis M. Tomazini
  13. Alcir Alves dos Santos
  14. Pedro Figueiredo
  15. Pâmela dos Santos Andrade
  16. Franciane Mendes de Oliveira
  17. Raissa Heloisa de Araújo Eliodoro
  18. Jaqueline Goes de Jesus
  19. Carolina dos Santos Lazari
  20. Ester C. Sabino
  21. Silvia F. Costa
  22. Antonio Carlos Pedroso de Lima
  23. Anna S. Levin

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Abstract

Background

CoronaVac, a vaccine containing inactivated SARS-CoV-2, demonstrated efficacy of 50.39% 14 days or more after the 2nd dose.

The objective of this study is to report the occurrence of symptomatic COVID-19 in a cohort of HCW vaccinated with CoronaVac and to estimate its effectiveness.

Methods

CoronaVac was given to HCWs inHospital das Clinicas on 18-21 January, 2021 (epi week 3) (22,402 HCWs), and on 14-16 February, 2021 (epi week 7) (21,652 HCWs). Weekly cases of symptomatic COVID-19 were evaluated. Using the period from 2020 epi week 24 through 2021 epi week 2 (before vaccination), a Poisson regression was fit to model the HCWs with COVID-19 of the hospital, and the officially reported cases in the city of São Paulo. The predicted numbers of cases among HCWs for 2021 epi weeks 3-12 were then compared to the observed numbers of cases (after vaccination). Effectiveness was estimated for weeks 9-12 (2 to 5 weeks after the 2nd dose). 142 samples after vaccination were evaluated for SARS-CoV-2 variants of concern.

Results

Since the 1st dose there were 380 HCW diagnosed with COVID-19. On visual analysis, the number of cases of COVID-19 in the city increased sharply in 2021. The number of cases among the HCW did not follow. The estimated effectiveness 2 and 3 weeks after 2nd dose was 50.7% and 51.8%, respectively, and increased over the next 2 weeks. 67/142 samples (47%) were variants of concern, mostly P1 (57).

Conclusion

Coronavac is effective in preventing COVID-19.

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  1. ScreenIT

    SciScore for 10.1101/2021.04.12.21255308: (What is this?)

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

    Table 1: Rigor

    Institutional Review Board Statementnot detected.
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.
    Sex as a biological variablenot 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:
    Our study has limitations. In the first place, it is a very preliminary evaluation in which details of affected patients such as severity of disease and deaths were not taken into account. Secondly, the peak of cases among HCWs in HC preceded the peak of cases in the city of São Paulo. We believe that this was due to the lack of diagnosis of mild and moderate cases in the city. In HC, testing was immediately available to all symptomatic HCWs since the beginning of the pandemic. In support of our idea, the peak of deaths in the city was similar to the cases in our HCWs. It has been discussed that deaths are a more reliable surveillance tool in situations in which testing capacity is limited [17, 18] which was especially true in the beginning of the pandemic in São Paulo. Considering this situation we chose not to include data from 2020 epi weeks 9 through 23 when designing our predictive model. As mentioned earlier, the results for 2021 epi weeks 10-12 should be interpreted with caution, as the numbers of cases in the city of São Paulo in these weeks were outside the range variation observed during parameter estimation of the Poisson regression model. In conclusion, since 2021 epi week 3, when the first dose of CoronaVac was administered to the HCW of the hospital, COVID-19 cases among our HCWs were lower than expected. São Paulo started a second wave of COVID-19 soon after the completion of vaccination in HC, that was not reflected among our HCWs.

    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.

    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.

  2. Version published to 10.1101/2021.04.12.21255308 on medRxiv