Flu Causes Heart Attacks But Vaccine Protects
September 22, 2009
WASHINGTON (Reuters) - Influenza can help trigger heart attacks and may account
for a 35 percent to 50 percent rise in heart attack deaths during flu season,
British researchers reported on Monday.
While a flu vaccine can prevent these deaths, fewer than half of the most
vulnerable heart patients in Britain actually get a flu vaccine every year,
however, they said.
"We believe influenza vaccination should be encouraged wherever indicated,
especially in those people with existing cardiovascular disease," Charlotte
Warren-Gash of University College London and colleagues wrote in the journal
Lancet Infectious Diseases.
"Further evidence is needed on the effectiveness of influenza vaccines to reduce
the risk of cardiac events in people without established vascular disease."
Warren-Gash and colleagues reviewed 39 studies conducted between 1932 and 2008
on the potential links between flu and heart deaths.
All the studies that covered entire populations showed a rise in deaths due to
heart disease or heart attacks when influenza viruses were circulating, they
found.
Seasonal influenza kills about 250,000 to 500,000 people a year, a figure that
experts came up with by carefully monitoring confirmed flu deaths in a small
area, counting excess deaths during influenza season over large populations, and
consolidating both calculations.
Warren-Gash's team found the proportion of excess influenza deaths that were due
to heart disease ranged from 35 percent to 50 percent.
Four out of eight studies showed people who were vaccinated from seasonal
influenza were less likely to have a heart attack they found.
But in Britain, only 47 percent of people with chronic heart disease, asthma,
diabetes or other conditions who are supposed to get a flu shot did last year.
Countries now are gearing up to vaccinate hundreds of millions of people against
the pandemic H1N1 swine flu and people with chronic heart disease are at the top
of the list of those who should get one.
SOURCE: Lancet Infectious Diseases, September 21, 2009.