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Effect of Vaccination Against Influenza Viruses on Infection, Hospitalization, and Death from Respiratory COVID-19: A Systematic Review and Meta-Analysis
35 Pages Posted: 26 Jul 2023
More...Abstract
The appearance of the severe acute respiratory syndrome coronavirus 2 (SARS‑CoV‑2) that causes coronavirus disease 2019 (COVID-19) has profoundly affected our societies and brought a huge burden in terms of human lives, especially because of the involvement of the cardiovascular system. In order to contain the spread of this new virus, strict social distance measures have been introduced in many countries. Similarly, anti-influenza vaccination was also highly recommended to avoid co-infections between influenza viruses and SARS-CoV-2 in the effort to decrease the risk of increased COVID-19 severity. Intriguingly, although influenza almost disappeared during the initial waves of COVID-19, scattered reports suggested an effect of the anti-influenza vaccination on COVID-19 development and/or severity. We analyzed 51 studies related to the capacity of anti-influenza vaccination to affect the infection with SARS-CoV-2 and found a significant effect of anti-influenza vaccination on the rate of SARS-CoV-2 infection and isolation in the intensive care unit (ICU), but not on hospitalization, or mortality. Our findings reveal the complexity of the relationship between the anti-influenza vaccination and the infection with SARS-CoV-2 related to healthcare workers, the general population, elderly individuals, sick individuals, and pregnant women. We also revealed that distinct types of anti-influenza vaccines differentially affect the protection against COVID-19, and we highlighted the impact of the distance between the anti-influenza vaccination and the encounter with SARS-CoV-2. Overall, our study stresses the importance of the anti-influenza vaccination in the protection against SARS-CoV-2 infection.
Funding: Ivan Zanoni is supported by NIH grants 2R01AI121066, 2R01DK115217, 1R01AI165505, 1R01AI170632, and contract no. 75N93019C00044, Lloyd J. Old STAR Program CRI3888, and holds an Investigators in the Pathogenesis of Infectious Disease Award from the Burroughs Wellcome Fund.
Declaration of Interest: The authors declare no conflict of interest.
Keywords: influenza, influenza vaccination, COVID-19, meta-analysis, SARS-CoV-2 infection, hospitalization, admission to intensive care units, mortality
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