People with heart failure are more susceptible to flu complications than other people. However, a new study has revealed that flu vaccinations may have a significant impact on lifespan.

Most doctors, scientists, and other medical professionals consider flu vaccinations to be a safe and effective way of protecting people against influenza, or the flu.

The vaccine, usually given in the form of an injection, contains small amounts of deactivated flu viruses.

These viruses are not harmful in this state but do trigger the human body to produce antibodies to fight against them. This means that the next time the virus enters the body, it can produce the same response quickly.

The Centers for Disease Control and Prevention (CDC) advises that everyone over the age of 6 months has a flu vaccination. However, certain individuals are more at risk of experiencing flu-related complications or even death.

This includes people over 65 years old and over, those who are pregnant, and those who have medical conditions, such as heart disease.

A new study has examined just how much of an impact a flu shot can have on the survival rate of people diagnosed with heart failure. This group of individuals are often older and are also likely to have a range of other health issues. For these people, getting the flu can be a severe problem.

The analysis

A team of researchers from the University of Copenhagen in Denmark analyzed data from a total of 134,048 Danish people who had recently received a diagnosis of heart failure. The researchers gathered the data from several national registries that store information on hospital diagnoses, prescriptions, and causes of death.

Each person born in Denmark receives a unique personal identification number, and this number allowed researchers to follow particular people for 12 years, from 2003 to 2015.

Many findings from the study came to light. The data analysis, now published in the American Heart Association's journal Circulation, firstly showed that the number of people getting flu vaccinations had increased.

In 2003, 16% of people with heart failure had the flu vaccine. In 2015, this had risen to 52% of people.

The researchers also found a link between flu vaccinations and "an 18% reduced risk of premature death." This reduction existed even after taking other factors, such as medications, other health issues, and financial situations, into account.

The importance of vaccines

The research also identified the importance of having regular flu shots. For example, people who had an annual flu vaccination after a diagnosis of heart failure showed a 19% reduction in cardiovascular death and all-cause death compared to those who did not get vaccinated.

Having the flu shot less than once a year resulted in an 8% reduction in the risk of cardiovascular death and "a 13% reduced risk of all-cause death" when compared to people who had never had the vaccination.

The final factor that the researchers identified was the timing of the flu vaccination. The team found a reduction in the number of cardiovascular and all-cause deaths when people received the vaccine at the beginning of the flu season, which is usually around September or October, rather than in November and December, for example.

Heart failure's future

Scientists expect heart failure to become an increasing problem in future years, making these results potentially useful for a human population that is now living longer. One limitation of this research, however, is that the scientists only studied people newly diagnosed with heart failure. Lead author of the study Daniel Modin says:

"While this research only looked at patients with newly diagnosed heart failure, the protection from a flu shot likely benefits any patient with heart failure."

—Daniel Modin

He continues, "I hope that our study can assist in making physicians and cardiologists who care for patients with heart failure aware of how important influenza vaccination is for their patients. Influenza vaccination may be regarded as a standard treatment in heart failure similar to medications."