Change in patterns of hospitalization for influenza during COVID‐19 surges

Abstract

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.

COVID-19 and Respiratory Virus Co-Infections: A Systematic Review of the Literature

“…Overall, 82.3% of SARS-CoV-2 and influenza co-infected patients were symptomatic at diagnosis [9][10][11][12][13][14][15]27,[60][61][62][63][64][65][66][67]. Despite the differences in terms of transmissibility and incubation period between SARS-CoV-2 and influenza viruses, co-infected patients usually manifested symptoms typical of COVID-19, including (new or persisting) fever (93.2%), cough (97.6%), (new or aggravated) shortness of breath/dyspnea (95.0%), diarrhea (93.8%), myalgia (44.1%), and fatigue (40.3%) [9,10,[12][13][14][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][50][51][52][53]58,[61][62][63].…”

Poor hospitalization outcomes in patients undergoing allogeneic hematopoietic stem cell transplant with hospital acquired influenza infection

“…10 Keeping in mind that our data are from the pre-pandemic era, it is possible that the rate of HAII in allo-HSCT patients has dropped even further due to the nationwide hospital reforms in the escalation of airborne and droplet precautions as well as the decrease in hospital visitors. 11 Although the risk of HAII is low in patients admitted for allo-HSCT, our analysis revealed that the patients that do contract influenza are at a significantly higher risk of poor hospital outcomes including death. Therefore, early recognition of symptoms and a low threshold for testing is critical, especially during the flu season.…”

“…Our large real‐world data of over 70 000 hospitalizations for allo‐HSCT reported a rate of less than 0.5% of HAIII, which reflects the excellent implementation of preventive strategies, including hand hygiene, gowning, and vaccination of healthcare staff at bone marrow transplant centers across the country 10 . Keeping in mind that our data are from the pre‐pandemic era, it is possible that the rate of HAII in allo‐HSCT patients has dropped even further due to the nationwide hospital reforms in the escalation of airborne and droplet precautions as well as the decrease in hospital visitors 11 . Although the risk of HAII is low in patients admitted for allo‐HSCT, our analysis revealed that the patients that do contract influenza are at a significantly higher risk of poor hospital outcomes including death.…”

Changes in hospitalizations and emergency department respiratory viral diagnosis trends before and during the COVID-19 pandemic in Ontario, Canada

“…Reductions were also observed for influenza, but evidence of a resurgence was sparse at the time of writing [36][37][38][39]. In Australia, where the seasonal surge in admissions is typically observed in the summer months, surveillance reporting from sentinel hospital sites revealed a return to pre-pandemic levels of hospital admissions for the 2022/23 season (the third since the pandemic began) with a peak in spring [40].…”

“…already taxed EDs and healthcare staff. Furthermore, the coexistence of SARS-CoV-2 and influenza in hospitalized patients was rare in the early pandemic, but co-infection is more likely in the upcoming 2022/23 influenza season and the implications of this on viral pathogenesis and patient outcomes remains unclear [38,41,42]. Alleviating strain on the healthcare system may include public health campaigns to promote influenza vaccination, further uptake of anti-RSV vaccination (maternal or among higher-risk infants and children) [43], and exploring RSV vaccination for older adults [44].…”