Influenza Vaccination and Hospitalizations Among COVID-19 Infected Adults

Area of Science:

• Infectious Diseases
• Immunology
• Public Health

Background:

• No effective treatments currently exist to decrease Coronavirus disease 2019 (COVID-19) hospitalizations.
• The influenza vaccine has been hypothesized to potentially reduce COVID-19 severity.

Purpose of the Study:

• To investigate the association between influenza vaccination status and COVID-19 severity.
• To determine if influenza vaccination impacts hospitalization and intensive care unit (ICU) admission rates in COVID-19 patients.

Main Methods:

• Retrospective cohort review of 2005 adult patients with a positive COVID-19 test at the University of Florida health care system.
• Analysis of comorbidities and influenza vaccination status.
• Logistic regression to assess the relationship between influenza vaccination and COVID-19 severity (hospitalization/ICU admission).

Main Results:

• COVID-19 patients unvaccinated against influenza in the past year had 2.44 times greater odds of hospitalization and 3.29 times greater odds of ICU admission compared to vaccinated patients.
• These associations remained significant after controlling for multiple comorbidities and demographic factors.
• The protective effect was observed irrespective of underlying health conditions.

Conclusions:

• Influenza vaccination appears to be potentially protective against moderate to severe COVID-19.
• The findings suggest that promoting influenza vaccination could mitigate COVID-19 morbidity and mortality.
• Further research is encouraged to explore the mechanisms, such as natural killer cell activation, and confirm generalizability.