Results of a two-year study involving 1,300 heart attack victims was
published recently in the American Journal of Epidemiology.
Contradicting prior claims that a flu shot might lower the risk of a
second heart attack, the study showed that receiving the influenza
vaccination reduced neither the likelihood of a second attack nor dying
due to heart disease.
"These results suggest that the benefit of influenza vaccine for
older adults does not extend to protection against recurrent coronary
events," the study's authors concluded.
"Although our results do not suggest a benefit of influenza
vaccine in the prevention of recurrent coronary events, the benefits of
the vaccine in preventing serious complications of influenza infection are
well documented," they wrote.
Yet, they failed to mention the potential side effects of the vaccine,
which include fever, fatigue, painful joints and headache. The most severe
reaction is Guillain-Barré Syndrome (GBS), a rare but serious adverse
reaction that can occur in two to four weeks of a vaccination. This
syndrome is a nerve disorder characterized by muscle weakness, unsteady
gait, numbness, tingling, pain and, sometimes, paralysis to one or more
limbs or to the face.
According to the National Vaccine Information Center (NVIC), the flu
vaccine is prepared from the fluids of chick embryos inoculated with a
specific type (or types) of influenza virus. The strains of flu virus in
the vaccine are inactivated with formaldehyde and preserved with
thimerosal, which is a mercury derivative.
"Every year, federal health agency officials try to guess which
three flu strains are most likely to be prevalent in the U.S. the
following year to determine which strains will be included in next year's
flu vaccine," the NVIC explained. "If they guess right, the
vaccine is thought to be 70-80% effective in temporarily preventing the
flu of the season in healthy persons less than 65 years old (the efficacy
rate drops to 30-40% in those over 65 years old but the vaccine is thought
to be 50-60% effective in preventing hospitalization and pneumonia and 80%
effective in preventing death from the flu in the over 65 age group).
However, sometimes health officials do not correctly predict which flu
strains will be most prevalent and the vaccine's effectiveness is much
lower for that year."
Although rarely mentioned by medical doctors when giving the shot, the
Centers for Disease Control (CDC) and the vaccine manufacturers list
recipients whose at-risk conditions should be noted before the vaccine is
administered. These include anyone sick with a fever, or who has an
impaired immune system, an egg or mercury allergy, or a history of GBS.
In years past, pregnancy was also a contraindication to flu vaccine
but, today, the CDC's Advisory Committee on Immunization Practices
recommends flu vaccine for women more than 14 weeks pregnant.
Still, the NVIC warns that pregnant women should be aware that the flu
vaccine contains thimerosal, which is a mercury derivative. Mercury is
toxic to the brain and has been found to be associated with brain damage
and developmental delays in babies whose mothers were exposed to high
levels of mercury during pregnancy.
SOURCES: "Influenza Vaccination Is Not Associated with a
Reduction in the Risk of Recurrent Coronary Events," by Lisa A.
Jackson, et al, American Journal of Epidemiology, October 1, 2002.
"The flu and the flu vaccine," National Vaccine Information
Center.
