Getting a seasonal flu shot may do more than just prevent
influenza. It may also lower a person's risk of heart problems, suggests a new
Researchers who took a fresh look at previously collected
data found people who got flu shots were less likely to have heart problems
during the next year than those who were given a fake shot, or placebo. That
was especially true for people with recent heart troubles. "If there are
those out there who for whatever reason don't get the flu shot or don't feel
that they need it... this is one more reason why they might help," Dr
Jacob Udell said.
Udell is the study's lead author from the University of
Toronto's Women's College Hospital and Peter Munk Cardiac Centre at Toronto
Previous reports have shown people who come down with the
flu have an increased risk over the near term of having a stroke, heart failure
and heart disease, he told Reuters Health. It’s thought the infection triggers
inflammation throughout the body and can aggravate existing heart problems.
For the new study, the researchers searched several
databases for trials that compared people who received the flu shot to others
who did not. They found five published studies and one unpublished study that
included 6 735 participants. Participants were in their late 60s, on average.
A little more than a third had a history of heart problems.
Overall, 3% of those who received a flu shot went on to have a heart problem including
a heart attack or stroke within a year. That compared to about 5% of those in
the placebo groups. Among those with recent heart disease, the difference was
The researchers found about 10% of participants with a
recent heart problem went on to have another after they received the flu shot.
That compared to about 23% in the placebo groups. "Clearly if you had a
recent heart attack our research is showing... they're going to derive the
most protection," Udell said. "I think it adds a stronger bit of
evidence to the recommendations that are currently being made," Dr David
Frid, a preventative cardiologist at the Cleveland Clinic in
Ohio, was not involved with the new study. "From the clinical perspective,
it gives us more supporting data to say to our patients, 'Here's a recent study
confirming what we've been telling you that if you have heart disease you
should be getting the flu vaccine,'" he told Reuters Health.
Dr Kathleen Neuzil from the global health nonprofit organisation
PATH in Seattle wrote an editorial accompanying the new study in The Journal of
the American Medical Association. She cautions that the findings can't say the
flu shot prevents heart problems. However, Neuzil writes that the known complications
of flu among older people warrant the vaccine's use.