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Vaccine Safety >
Issues of Interest > GBS
Guillain-Barre
Syndrome (GBS) and
Influenza Vaccine
Questions
answered on this page:
- What
is Guillain-Barre Syndrome?
- What
causes GBS?
- How
often does GBS occur after influenza vaccination?
- Should
I receive the influenza vaccine?
- If
I have had GBS, should I receive influenza
vaccine?
Articles
on this topic:
Institute
of Medicine Report: ...Guillain-Barré
Syndrome Linked Only to 1976 Swine Flu Vaccine
(released Oct. 6, 2003)
Each year with the beginning of the annual
influenza season, there are questions about
influenza vaccine, a medical condition known
as Guillain-Barre Syndrome (GBS) and their
possible association.
- What
is Guillain-Barre Syndrome?
GBS
is a rare neurological disease characterized
by loss of reflexes and temporary paralysis
usually beginning in the lower extremities
(legs) and moving to the upper extremities
(arms).
The main symptoms of GBS are weakness, numbness,
tingling, prickling and increased sensitivity
that spreads over the body. Muscle paralysis
usually starts in the feet and legs, and
can sometimes involve respiratory muscles
that help with breathing. The symptoms of
GBS usually appear over the course of a single
day and may continue to progress for 3 or
4 days up to 3 or 4 weeks. The symptoms in
more than 90 percent of the cases reach a
peak by 4 weeks. Although fatal in five percent
or less of cases, recovery usually begins
within 2 to 4 weeks after the progression
stops. In some cases recovery may be delayed
for months. However, while most patients
recover functionally; some persistent symptoms
may be present in 15-20% of patients.
 Top
- What
causes GBS?
The actual cause(s) of GBS are unknown, but
the most common predisposing conditions to
GBS are bacterial or viral infections, or
surgery.
More than half of all patients with GBS have
a history of an acute infectious illness,
in the 1 to 4 weeks prior to the onset of
neurologic symptoms.
Recently, Campylobacter, a bacteria commonly
found inadequately cooked food, especially
poultry, has been implicated as one of the
likely causes of GBS. There have been rare
reports of GBS after the administration of
some vaccines. The 1976 swine influenza vaccine
was shown to increase the rate of GBS by
slightly less than one case per 100,000 vaccinations.
Unlike the 1976 swine influenza vaccine,
subsequent vaccines prepared from other virus
strains have not been clearly associated
with an increased frequency of GBS.
Top
- How
often does GBS occur after influenza vaccination?
The vast majority (>99%) of patients with
GBS have not recently received a vaccination.
Reports of GBS after the administration of
vaccines are therefore rare. In most cases
where GBS developed after an immunization,
proof that the vaccine caused GBS has not
been established.
The risk of developing GBS following immunization
is therefore extremely small if at all. Even
when there has been a suggestion of a causal
association, it is likely to have been no
more than 1-2 cases of GBS per million vaccinations.
Obtaining a precise estimate of a small increase
in risk is difficult for a rare condition
such as GBS, which has an annual background
incidence of only 1 to 2 cases per 100,000
adult population.
Top
- Should
I receive the influenza vaccine?
Yes, if you are 65 years of age or over and
are in a high risk group. For other persons,
you may wish to seek advice from your health
care provider. The estimated risk of GBS,
if it exists, is substantially less than
that of severe influenza.
Top
- If I have
had GBS in the past, should
I receive influenza vaccine?
The incidence of GBS in the general population
is very low, persons with a history of GBS
have a greater chance of developing GBS than
persons without such a history. Thus, the
likelihood of developing GBS is expected
to be greater among persons with a history
of GBS than among persons with no history
of this syndrome. Whether influenza infection
or influenza vaccination might be causally
associated with this risk for GBS recurrence
is not known. For persons known to have developed
GBS within 6 weeks of a previous influenza
vaccination, avoiding future influenza vaccinations
may be prudent. Other persons with a history
of GBS are likely to be at increased risk
of complications from influenza disease.
The established benefits of influenza vaccination
probably justify their receipt of annual
influenza vaccinations.
Top
References
Adverse Events
Associated with Childhood Vaccines, Institute
of Medicine, Evidence Bearing on Causality,
Institute of Medicine, 1994, page 37-47.
Epidemiology
and Prevention of Vaccine Preventable Diseases,
4th Edition, The Pink Book, Centers for Disease
Control, September 1997.
MMWR, Vol. 46/No.
RR-9, April 25, 1997, page 8-9.
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