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Change in patterns of hospitalization for influenza during COVID-19 surges
Sindhaghatta Venkatram1, Anuhya Alapati1, Arundhati Dileep1
1Division of Pulmonary and Critical Care Medicine, BronxCare Health System, Affiliated with Icahn School of Medicine at Mount Sinai, New York, NY, USA.
Insights
Influenza hospitalizations decreased during the COVID-19 pandemic, with no change in patient outcomes or mortality. Identifying the specific virus, such as influenza or coronavirus disease 2019 (COVID-19), remains crucial for treatment.
Area of Science:
- Infectious Diseases
- Epidemiology
- Public Health
Background:
- Influenza hospitalization rates were stable prior to 2020.
- The emergence of coronavirus disease 2019 (COVID-19) raised concerns about potential coinfections with influenza.
- Similar clinical presentations of influenza and COVID-19 necessitated comparative analysis.
Purpose of the Study:
- To compare the incidence and clinical outcomes of influenza hospitalizations before and during the COVID-19 pandemic.
- To assess the impact of COVID-19 on influenza patient outcomes, including mortality.
- To identify factors influencing mortality in hospitalized influenza patients.
Main Methods:
- Retrospective study of hospitalized patients with influenza from 2017 to 2021.
- Comparison of influenza incidence and clinical outcomes across four influenza seasons (pre- and during COVID-19).
- Analysis of patient demographics, comorbidities, coinfections, and mortality predictors.
Main Results:
- A significant decrease in influenza hospitalization incidence was observed during the COVID-19 pandemic.
- No differences in clinical outcomes or mortality were found for influenza patients when comparing pre- and during-pandemic periods.
- Influenza patients during the pandemic had a 4.4% coinfection rate with COVID-19 and 7.8% with bacterial superinfections; COVID-19 coinfection did not increase mortality.
Conclusions:
- Influenza hospitalization rates declined during the COVID-19 pandemic, but clinical outcomes remained stable.
- Bacterial pneumonia and coinfection with COVID-19 did not significantly increase mortality in influenza patients.
- Accurate viral diagnosis is critical for effective therapeutic management of respiratory infections.
Background:
Hospitalization due to influenza has been stable in recent years. In March 2020, New York was an epicenter for coronavirus disease 2019 (COVID-19). Because influenza and COVID-19 present similarly, there were serious concerns that coinfection of these viruses would burden the healthcare system. We compared incidence and outcomes of patients hospitalized with influenza before and during COVID-19 (seasons 2017-2021).
Methods:
We conducted a retrospective study evaluating hospitalized patients with influenza. Four influenza seasons were evaluated, 2017-2021, pre- and during COVID-19 pandemic. We compared incidence of influenza and clinical outcomes across the seasons.
Results:
We found 412 patients hospitalized due to influenza in the study period; 394 had influenza, and 18 had both influenza and COVID-19 infections. Demographics across the four influenza seasons were comparable; the cohort was predominantly female (61%) and had an average age of 60 years old. Comorbid conditions were common. No outcome differences were found for patients with influenza when comparing influenza seasons prior to and during the COVID-19 pandemic. The mortality for the entire cohort was 6.5%. During the COVID-19 pandemic, there were 18 (4.4%) influenza patients coinfected with COVID-19 and 32 (7.8%) patients with bacterial super infection. Predictors of mortality in patients with influenza included presence of shock, heart failure, bacterial pneumonia, and use of mechanical ventilation. Coinfection with COVID-19 did not increase mortality.
Conclusion:
We observed a significant decrease in the incidence of hospitalization due to influenza during the COVID-19 pandemic. Clinical presentations and outcomes for patients with influenza remain stable. Being aware of possible increased mortality for patients with both influenza and bacterial pneumonia is important. Although coinfection with COVID-19 did not increase mortality in influenza patients, identifying the specific virus responsible for infections has major therapeutic implications.
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