Christian F. Christiansen
In Denmark, elderly ICU survivors who received an influenza vaccine had an 8% decreased risk for death and a 16% reduced risk for hospitalization for stroke in the year after discharge compared with patients who were not vaccinated, according to findings from a population-based cohort study published in Intensive Care Medicine.
“Patients aged 65 years or older who survive a hospitalization with intensive care admission are at high risk of morbidity and mortality within the first year after discharge,” Christian F. Christiansen, MD, PhD, associate professor of clinical epidemiology at Aarhus University Hospital in Denmark, told Infectious Disease News. “Our study shows that there are fewer deaths and strokes within the first year after discharge in intensive care survivors who have been vaccinated against influenza compared with unvaccinated individuals.”
According to Christiansen and colleagues, 1-year mortality after hospital discharge among ICU patients aged 65 years or older ranges between 21% and 27% — three to four times higher than the mortality rate for the general population of the same age. As more critically ill elderly patients are admitted to ICUs and surviving intensive care, “long-term morbidity and mortality after the immediate critical illness are major concerns in this fragile population,” and any benefits from influenza vaccination among these patients would have a significant clinical impact, they noted.
The researchers analyzed data from the Danish Intensive Care Database from 2005 through 2015 and included 89,818 ICU survivors aged 65 years or older in the study. The patients who were vaccinated for influenza (n = 34,871; 39%) were older, used more prescription medications and had more chronic diseases than the unvaccinated patients, according to the study. Vaccinated patients had an adjusted 1-year mortality of 19.3% vs. 18.8% for unvaccinated patients (adjusted HR = 0.92; 95% CI, 0.89-0.95), Christiansen and colleagues reported. Vaccination also was associated with a decreased risk for stroke (adjusted HR = 0.84; 95% CI, 0.78-0.92), but the researchers found no association between vaccination and subsequent hospitalization for pneumonia or heart failure.
“We can only speculate about the potential mechanisms as our study did not provide such data,” Christiansen said. “There is growing evidence linking infection and inflammation to cardiovascular events, and it is possible that preventing influenza infection may decrease the risk of cardiovascular events, including stroke. Others suggest a nonspecific immunomodulatory effect of the vaccine itself, which may influence the outcome of critical illness.”
Christiansen said the study’s findings support current recommendations that influenza vaccination be provided to high-risk groups, including individuals aged 65 years or older. – by Joe Gramigna
Disclosures: The authors report no relevant financial disclosures.