The influenza vaccine is associated with a reduced risk of hospitalisation in patients with heart failure, according to a large UK study.
The research, involving around 60,000 patients, appears to ends the controversy over flu vaccination in heart failure patients and provides more robust evidence for current recommendations.
“More efforts are needed to ensure that heart failure patients receive an annual flu jab”
The researchers noted that uptake of the flu vaccination in heart failure patients was relatively low, being around 50-70% in countries like the UK.
They said more evidence had been needed on whether flu jabs could reduce adverse events in patients with heart failure, which would provide the impetus to improve uptake.
The study authors looked at data on 59,202 heart failure patients using the Department of Health’s Clinical Practice Research Datalink from 1990 to 2013.
Flu vaccination was associated with a 30% lower risk of admission for cardiovascular diseases, 16% lower risk for respiratory infections and 4% lower risk of all-cause hospitalisation in the period 31 to 300 days after vaccination, compared with the corresponding period in a vaccination-free year.
Flu jab associated with fewer heart failure admissions
Study author Professor Kazem Rahimi, deputy director of the George Institute for Global Health at Oxford University, said: “These findings do not suggest that influenza infection causes myocardial infarction or other cardiovascular events.
“A more likely explanation for the reduction in risk of cardiovascular hospitalisation is that vaccination reduces the likelihood of an infection which could in turn trigger cardiovascular deterioration,” he said.
He added: “The relative effect seems to be smaller for respiratory infections which may be due to fact that the vast majority of these hospitalisations are not related to influenza and in our study we were not able to distinguish between the different types of respiratory infection.”
The observed links between immunisation and admission were largest 31 to 120 days after vaccination and in patients aged under 66. There were no differences between men and women.
Professor Rahimi said that based on the findings “more efforts are needed to ensure that heart failure patients receive an annual flu jab”.
Meanwhile, a separate study in Taiwan has suggested influenza vaccination is associated with a lower risk of dementia in patients with heart failure.
The study involved 20,509 patients with heart failure, of which 10,797 received at least one flu jab and the other 9,712 were not vaccinated during a 12-year period.
“This is an important prospect for dementia prevention”
Patients who had received the jab were 35% less likely to develop dementia than those who had not and those who had been vaccinated more than three times had a 55% lower dementia risk. The largest protective effect was observed in patients over 70 and if they were male.
Study author Dr Ju-Chi Liu, director of cardiovascular medicine at Taipei Medical University, said “Previous studies have shown that there is link between impairment in cognitive function and heart failure.
“We think that the flu virus can activate the immune response and cause inflammation which may injure the brain cells,” he said. “Respiratory infection during flu can induce changes in blood pressure and heart rate, which may also harm the brain tissue.
“These effects of the flu could play a role in the development of dementia, particularly in heart failure patients who already have impaired circulation in the brain,” said Dr Liu.
He added: “If influenza vaccination can prevent the inflammation induced by flu, it may decrease the risk of dementia in heart failure patients. This is an important prospect for dementia prevention.”
Both studies were presented at a European Society of Cardiology conference in Florence yesterday – Heart Failure 2016 and the 3rd World Congress on Acute Heart Failure.