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. 2023 Feb;16(2):250-256.
doi: 10.1016/j.jiph.2022.12.016. Epub 2022 Dec 26.

Effectiveness of influenza vaccination against SARS-CoV-2 infection among healthcare workers in Qatar

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Effectiveness of influenza vaccination against SARS-CoV-2 infection among healthcare workers in Qatar

Elias Tayar et al. J Infect Public Health. 2023 Feb.

Abstract

Background: Some studies have reported that influenza vaccination is associated with lower risk of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and/or coronavirus disease 2019 (COVID-19) morbidity and mortality. This study aims to estimate effectiveness of influenza vaccination, using Abbott's quadrivalent Influvac Tetra vaccine, against SARS-CoV-2 infection and against severe COVID-19.

Methods: This matched, test-negative, case-control study was implemented on a population of 30,774 healthcare workers (HCWs) in Qatar during the 2020 annual influenza vaccination campaign, September 17, 2020-December 31, 2020, before introduction of COVID-19 vaccination.

Results: Of 30,774 HCWs, 576 with PCR-positive tests and 10,033 with exclusively PCR-negative tests were eligible for inclusion in the study. Matching by sex, age, nationality, reason for PCR testing, and PCR test date yielded 518 cases matched to 2058 controls. Median duration between influenza vaccination and the PCR test was 43 days (IQR, 29-62). Estimated effectiveness of influenza vaccination against SARS-CoV-2 infection> 14 days after receiving the vaccine was 29.7% (95% CI: 5.5-47.7%). Estimated effectiveness of influenza vaccination against severe, critical, or fatal COVID-19 was 88.9% (95% CI: 4.1-98.7%). Sensitivity analyses confirmed the main analysis results.

Conclusions: Recent influenza vaccination is associated with a significant reduction in the risk of SARS-CoV-2 infection and COVID-19 severity.

Keywords: COVID-19; Case-control; Epidemiology; Immunity; Influenza; Vaccine.

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Conflict of interest statement

Conflict of interest The authors declare no conflict of interest.

Figures

Fig. 1
Fig. 1
Flowchart describing the population selection process for investigating effectiveness of influenza vaccination against SARS-CoV-2 infection.

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References

    1. Jackson M.L., Chung J.R., Jackson L.A., Phillips C.H., Benoit J., Monto A.S., et al. Influenza Vaccine Effectiveness in the United States during the 2015-2016 Season. N Engl J Med. 2017;377(6):534–543. PubMed PMID: 28792867. Pubmed Central PMCID: PMC5727917. Epub 2017/08/10. - PMC - PubMed
    1. Pearson M.L., Bridges C.B., Harper S.A. Healthcare infection control practices advisory C, advisory committee on immunization P. Influenza vaccination of health-care personnel: recommendations of the healthcare infection control practices advisory committee (HICPAC) and the Advisory Committee on Immunization Practices (ACIP) MMWR Recomm Rep. 2006;55(RR-2):1–16. PubMed PMID: 16498385. Epub 2006/02/25. - PubMed
    1. Conlon A., Ashur C., Washer L., Eagle K.A., Hofmann, Bowman M.A. Impact of the influenza vaccine on COVID-19 infection rates and severity. Am J Infect Control. 2021;49(6):694–700. PubMed PMID: 33631305. Pubmed Central PMCID: PMC7899024. Epub 2021/02/26. - PMC - PubMed
    1. Fink G., Orlova-Fink N., Schindler T., Grisi S., Ferrer A.P.S., Daubenberger C., et al. Inactivated trivalent influenza vaccination is associated with lower mortality among patients with COVID-19 in Brazil. BMJ Evid Based Med. 2020 PubMed PMID: 33310766. Pubmed Central PMCID: PMC7735072. Epub 2020/12/15. - PubMed
    1. Huang K., Lin S.W., Sheng W.H., Wang C.C. Influenza vaccination and the risk of COVID-19 infection and severe illness in older adults in the United States. Sci Rep. 2021;11(1):11025. PubMed PMID: 34040014. Pubmed Central PMCID: PMC8155195. Epub 2021/05/28. - PMC - PubMed

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