Flu vaccines provide
virtually no benefit to children. That's the
conclusion of a new review of all relevant
studies. Interestingly, the news comes at a time
when some health officials have begun to
recommend the vaccination of all children in
order to prevent them from passing on the flu to
their elderly relatives. The review follows on
the heels of a study that looked at three
decades' worth of data and found that vaccines
for the elderly are not as effective as
previously thought. And contrary to conventional
medical wisdom, vaccines do not seem to reduce
flu-related deaths in elderly people.
To determine the value of flu vaccines to
children, Tom Jefferson, MD, and colleagues at
the Cochrane Collaboration looked at over a
thousand studies. They selected 14 high-quality
clinical trials in which vaccinated children had
been compared with unvaccinated children. The
combined results of these 14 trials were
reported in the British journal The Lancet
(2/26/05). Here's the conclusion: “We recorded
no convincing evidence that vaccines can reduce
mortality, [hospital] admissions, serious
complications, and community transmission of
influenza.”
The best the Cochrane reviewers could come up
was this: “Vaccines were somewhat effective at
reducing school absence…” Though the U.S.
Centers for Disease Control (CDC) and Prevention
advises flu vaccines for babies 6-23 months
because they tend to suffer more complications
once they get the flu, no evidence supports the
recommendation. The Cochrane reviewers found
that vaccines had little effect on bronchitis,
ear infections, and hospitalizations, compared
with the babies given placebo vaccines. In
short, the CDC recommendations are irresponsible
given the fact that the only two studies that
involved babies found no benefit and little is
known about adverse effects of these vaccines
for babies.
Benefit to Elderly overrated
Now for the importance of flu vaccines to the
elderly. A new comprehensive study cast doubt on
the widespread belief that flu vaccines save
lives (Archives of Internal Medicine, 2/14/05).
Though the authors work for a federal government
health agency, they produced evidence that
failed to support CDC recommendations.
Lone Simonsen, PhD, and colleagues at the
National Institute of Allergy and Infectious
Diseases conducted a review of 33 consecutive
flu seasons, from 1968 to 2001. The authors
began their report with an acknowledgement that
an accurate assessment of flu-related deaths is
virtually impossible because few cases are
confirmed with blood tests. And the viral
infection is usually cleared from the body
before the appearance of complications that
cause death. For these reasons, the authors had
to use a special statistical method to estimate
flu-related deaths and deaths from all causes
among elderly Americans over the
three-decade-period.
Here is what Dr. Simonsen and colleagues found:
-The number of flu-related deaths among elderly
Americans increased steadily during the
33-year-period, despite the fact that their
acceptance of flu vaccinations also steadily
increased. For example, only 20% of all elderly
Americans had a flu shot in 1980, compared with
65% in 2001.
-There was a decline in flu-related deaths among
people 65-74 years in the decade after the 1968
flu pandemic because people had naturally
acquired immunity due to exposure to the
emerging viruses of that period. The increasing
flu vaccine coverage after 1980, however, did
not correlate with a decline in flu-related
deaths.
-The over-all death rate for people over 85
during flu seasons did not change over the
33-year-period. Dr. Simonsen and colleagues cite
earlier research that might provide an
explanation for why flu vaccines did not reduce
the flu-related deaths in “the very elderly”
after 1980 when vaccine coverage began to
increase, “...antibody responses following
influenza vaccination decline sharply after age
65 years and a clinical trial involving subjects
60 years or older...found that the efficacy of
influenza vaccine in preventing influenza
illness was lower in people older than 70
years.”
Because fewer than 10% of all winter deaths can
be attributed to the flu in any year during this
study's three-decade period, the authors
conclude that vaccination's benefit to elderly
people has been substantially overestimated.
Maryann Napoli, Center for Medical Consumers (C)
March 2005.