Flu vaccine may also protect against blood clot formation
New research has observed that, in elderly, hospitalized patients, prior flu vaccination reduced patients’ morbidity, blood clot and cranial bleeding risks, compared with unvaccinated patients.
Previous research has demonstrated a correlation between flu vaccination and reduced bacterial infection, and heart attack risks in young patients. Based on this, a novel, Danish study, carried out at Aarhus University Hospital (Denmark), has investigated the health impacts of influenza vaccination, specifically in elder individuals.
In this register-based, cohort study, researchers assessed data on 89,818 elderly patients – over the age of 65 years – who had survived hospitalization on an intensive care unit between 2005 and 2015.
Eligible study participants were identified using the Danish Intensive Care Database. Propensity matching was employed to mitigate the effects of confounding factors and Cox proportional hazards regression was utilized to calculate hazard ratios representing patients’ relative risk of adverse outcomes.
In the study, researchers observed that hospitalized, elderly, critically ill patients, who had been vaccinated against influenza, had reduced mortality, blood clot and cranial bleeding risks, compared with unvaccinated individuals.
Regardless of the cause of hospital admission, vaccinated individuals were 16% less likely to suffer a stroke event, compared with non-vaccinated patients.
Further, researchers observed that vaccinated patients had a lower all-cause mortality risk, during the year following their hospital discharge, compared with individuals who were not vaccinated. The comparative hazard ratio of these patient cohorts was 0.92.
Christian Fynbo Christiansen, Clinical Associate Professor and Consultant at Aarhus University Hospital, noted: “Every year, 30,000 people are admitted to the intensive care units in Danish hospitals…Approximately three out of four survive the hospitalization and are discharged from hospital. But even among the patients who are discharged, almost one in five die within the first year while many others suffer complications.”
Christiansen continued: “Our study shows that there are fewer deaths and serious complications among the patients who have been vaccinated against influenza…this supports the current recommendation that elderly people should be vaccinated.”
Christiansen CF, Thomsen RW, Schmidt M, Pedersen L, Sørensen HT. Influenza vaccination and 1-year risk of myocardial infarction, stroke, heart failure, pneumonia, and mortality among intensive care unit survivors aged 65 years or older: a nationwide population-based cohort study. Intensive Care Med. 45(7), 957–967 (2019);