Influenza vaccination status and outcomes among influenza-associated hospitalizations in Columbus, Ohio (2012–2015)

Abstract

Prior studies suggest that the influenza vaccine is protective against some outcomes in hospitalized patients infected with influenza despite vaccination. We utilized surveillance data from Columbus, Ohio to investigate this association over multiple influenza seasons and age groups. Data on laboratory-confirmed influenza-associated hospitalizations were collected as a part of the Influenza Hospitalization Surveillance Project for the 2012-2013, 2013-2014, and 2014-2015 influenza seasons. The association between influenza vaccination status was examined in relation to the outcomes of severe influenza and diagnosis of pneumonia among patients receiving antiviral treatment. Data were analyzed using multivariable logistic regression. We observed no overall association between influenza vaccination status and severe influenza among hospitalized patients. During the 2013-2014 season, those who were vaccinated were 41% less likely to be diagnosed with pneumonia compared with those who were unvaccinated (OR = 0·59 95% CI 0·41-0·86). The influenza vaccine may provide a secondary preventive function against pneumonia among influenza cases requiring hospitalization. However, a protective effect was only observed in 2013-2014, an influenza H1N1 dominant year. Differences in circulating influenza virus strains and vaccine matching to the circulating strains during influenza seasons may impact this association.

Behavior of hospitalized severe influenza cases according to the outcome variable in Catalonia, Spain, during the 2017–2018 season

“…This finding could be explained because vaccinated could attend to the hospital more frequently than do unvaccinated subjects as suggested by Casado et al 32 in a study carried out in older adults in 2013–2014 and 2014–2015 season. However, residual confounding by comorbid conditions could not be ruled out as suggested by other authors 33 because patients with comorbidities (79% in our study) are more likely to access healthcare resources and subsequently have more opportunities to receive the influenza vaccine. On the other hand, as suggested by Gutiérrez-González et al 17 because only hospitalized severe cases are included in the study, the protection for fatal episodes might be underestimated.…”

Contemporary management of severe influenza disease in the intensive care unit

“…Furthermore, it's unclear whether the potential benefits of NAIs seen in these studies would also apply to patients with non-pandemic strains of influenza or whether these benefits would be seen in vaccinated vs. unvaccinated patients. This is of importance as prior studies have demonstrated that influenza vaccination may protect against secondary pneumonia, but this may be dependent upon the circulating influenza strain [11]. Oseltamivir is generally well-tolerated; however, neuropsychiatric events such as delirium, hallucinations, and behavioral changes or rare dermatologic reactions (e.g.…”

“…Limited data exist regarding absorption of oseltamivir and drug concentrations in critically ill patients with one pharmacokinetic study suggesting drug concentrations obtained in critically ill patients do not differ from ambulatory patients as described above [11]. Furthermore, there is no evidence to suggest differences in clinical outcomes based on oseltamivir dose.…”