Vaccines generally safe, National Academy of Sciences saysBy Rob
, Published: August 25

Vaccines are generally safe for most people, the National Academy of
Sciences has concluded, dismissing stubborn concerns about supposed links to
autism and other serious health problems.

In the academy’s first comprehensive review of vaccine safety in 17 years, a
committee of experts formed by the Institute of Medicine analyzed more than
1,000 research studies. They concluded that benefits outweigh the risks,
which are rare and usually not life-threatening.

In a 667-page report <> released
Thursday, the 16-member committee found convincing evidence that vaccines
can cause 14 health problems, including seizures, brain inflammation, rashes
and fainting, but said those complications appeared to be very uncommon. The
committee also concluded there was evidence that some vaccines could cause
other complications, such as allergic reactions and temporary joint pain.

But the committee found no link between being immunized and the most serious
health problems that have raised concern, including autism and Type 1

“We have a lot of evidence that vaccines save lives and avert a lot of
suffering,” said Ellen Wright Clayton, a professor of pediatrics and law at
Vanderbilt University who chaired the committee. “The side effects we’re
talking about here are really relatively rare . . . and the majority of the
ones we found are either short-term or easily treated. That would be the
take-home message.”

The safety of vaccines has become the subject of intense debate in the
United States and elsewhere in recent years. Some parents have expressed
concern that the rising number of inoculations recommended for children
might be causing complications, leading some to refuse to get their children
vaccinated against diseases such as measles, mumps and whooping cough.

Many public health authorities, however, have become increasingly alarmed
that the refusals have led to a resurgence of infectious diseases that were
once common killers but had been largely eliminated through wide-scale
vaccination. In fact, a large outbreak of measles occurred in Europe this
year, and the number of cases being reported in the United States this year
has surged. This week, Maryland and Virginia health officials warned
passengers who took an Amtrak train from Boston to Virginia last week that
they may have been exposed to measles from an infected passenger. California
has reported a resurgence of whooping cough.

*‘Remarkably safe’*

Many prominent medical groups have repeatedly concluded that the benefits of
vaccines outweigh the risks, and the purported link between autism and
childhood vaccines has been uniformly disputed by leading authorities. But
the new report is the most comprehensive look at the subject by one of the
most prestigious scientific organizations. Vaccine proponents hoped that it
would encourage more parents to get their children vaccinated.

“Although vaccines can cause certain problems rarely, on balance they are
remarkably safe,” said Paul A. Offit, chief of infectious diseases at
Children’s Hospital of Philadelphia.

The committee reviewed the existing scientific evidence for every commonly
used vaccine and the complications possibly associated with each. It
determined whether the studies showed that each vaccine clearly caused each
possible complication, may have caused each complication, clearly did not
cause any complications or whether there was insufficient evidence to know
one way or the other.

Clayton acknowledged that there were more than 100 conditions for which the
scientific evidence was inadequate to make a clear determination. The
experts also could not quantify exactly how frequently side effects occur.
That prompted critics of vaccines to question the report’s conclusions.

“The committee’s clear acknowledgment that there is a lack of adequate
scientific understanding about the way that vaccines act in the human body,
including how, when, why and for whom they are harmful, is confirmation that
more and higher quality vaccine safety science is urgently needed,” Barbara
Loe Fisher of the National Vaccine Information Center said by e-mail.

The Institute of Medicine has reviewed the safety of vaccines 11 times at
the request of Congress since it enacted the National Childhood Vaccine
Injury Act in 1986, with the last review occurring in 1994. The Department
of Health and Human Services uses the reviews to administer the Vaccine
Injury Compensation Program, which compensates the families of children
injured by vaccines.

The committee concluded that there was convincing evidence that the
measles-mumps-rubella (MMR) vaccine can lead to seizures triggered by fevers
in some people. But that complication was almost always short-lived and did
not lead to serious complications, the experts determined. The MMR vaccine
can also cause a rare form of brain inflammation in some people with severe
immune-system problems, the panel said.

“We looked very hard, and we did not find many adverse effects,” Clayton
said. “I think that’s really good news.”

In a minority of patients, the chickenpox vaccine can cause brain swelling,
pneumonia, hepatitis, meningitis, shingles or chickenpox, the committee
found. But most of those cases occurred in people with immune system
problems, according to analysis.

The MMR, chickenpox, flu, hepatitis B, tetanus and meningococcal vaccines
can all cause an allergic reaction known as anaphylaxis shortly after
getting the injections, as well as fainting and inflammation, the committee
said. There is also weaker evidence that the vaccine can cause short-term
joint pain in some women and children, according to the study, and some
people can experience anaphylaxis after getting vaccinated against the human
papillomavirus (HPV).

But the flu shot does not cause Bell’s palsy or worsen asthma, as had been
feared, the committee concluded.

And while many studies have examined whether flu shots can cause
Guillain-Barre syndrome, a neurological disorder, the committee was unable
to say with certainty whether there was or was not a cause-and-effect

*‘No’ autism risk*

While it is impossible to prove there is no link between vaccines and
autism, Clayton said, the weight of the evidence appears convincing.

“There have been a number of very strong studies looking at a large number
of people. They consistently show no risk” for autism from the MMR vaccine,
Clayton said.

The report’s release coincided with new federal data that showed that only
about half of U.S. teenage girls had gotten vaccinated against HPV, a
sexually transmitted virus that can cause cervical cancer. The vaccine has
been dogged by concerns about safety and fears that the vaccine might
encourage sexual activity. But Melinda Wharton of the Centers for Disease
Control and Prevention said studies show that the vaccine is highly
effective and safe.

“We’re talking about preventing cervical cancer,” Wharton said. “Not as many
of our nation’s girls are receiving this life-saving vaccine as they


Michael Balter
Contributing Correspondent, Science
Adjunct Professor of Journalism,
New York University

Email:  [log in to unmask]

“Faced with the choice between changing one’s mind and proving that there is
no need to do so, almost everyone gets busy on the proof."
                                                  --John Kenneth Galbraith