No evidence of increased risk of Guillain-Barre syndrome following vaccination
Patients are not at increased risk of Guillain-Barré syndrome in the six-week period after vaccination with any vaccine, including influenza, according to a Kaiser Permanente study published in Clinical Infectious Diseases.
The retrospective study by researchers at the Kaiser Permanente Vaccine Study Center spanned 13 years and was controlled for seasonality.
“If there is a risk of Guillain-Barré syndrome following any vaccine, including influenza vaccines, it is extremely low,” said Roger Baxter, MD, co-director of the Kaiser Permanente Vaccine Study Center.
During the 13-year period (1994-2006), 415 confirmed cases of Guillain-Barré syndrome were observed. Within this group, the researchers found only 25 patients had received any vaccine in the six weeks prior to the onset of the disease. The study also found that 277 patients had a respiratory or gastrointestinal illness in the 90 days preceding the onset.
Guillain-Barré syndrome is an acute disease thought to be an autoimmune disorder resulting in destruction of a nerve’s myelin sheath and peripheral nerves. In many cases, the syndrome is temporally associated with an infectious disease; most published case series report that approximately two-thirds of all cases are preceded within three months by a gastrointestinal or respiratory infection. Guillain-Barré syndrome had been linked to the influenza vaccine in a 1976 study, but not clearly since. There have been reports of an association with other vaccines, which have not been confirmed.
Previous studies of Guillain-Barré syndrome as a possible adverse event related to vaccines have been subject to confounding by differences between vaccinated and unvaccinated individuals which may be unmeasured, said Dr. Baxter, who led the team that conducted this new research.
The Vaccine Study Center researchers further explained that variables that change over time – like infectious diseases or rates of vaccination – can lead to confusion in observational studies, which look at already collected data rather than randomizing people to treatment versus placebo. For this reason, they said, it is necessary to use special epidemiologic and statistical methods to overcome these variables.
The case-centered study design used to conduct this research focuses on the outcome, then looks back to determine vaccination status. This method can control for many of the variables that change over time and, consequently, lead to a more accurate assessment of Guillain-Barré syndrome risk or recurrence following vaccination.
Guillain-Barre’ syndrome (say “ghee-YAN bah-RAY”) is a problem with your nervous system. It causes muscle weakness, loss of reflexes, and numbness or tingling in your arms, legs, face, and other parts of your body.
Guillain-Barre’ syndrome (GBS) can cause paralysis and lead to death. But most people get better and have few lasting problems.
GBS is rare.
What causes Guillain-Barre’ syndrome?
Experts don’t know what causes GBS. They think that the nerves are attacked by your body’s own defense system (the immune system). This is called an autoimmune disease.
In GBS, the immune system attacks the covering (myelin sheath camera) of certain nerves. This causes nerve damage.
Infections that may trigger GBS
GBS usually begins to affect the nerves after you’ve had a viral or bacterial infection. Often it is after an infection of the lungs or stomach and intestines.
Infections that may trigger GBS include:
Campylobacter jejuni, which can cause a type of food poisoning.
Mycoplasma , which can cause pneumonia.
Cytomegalovirus (CMV), which can cause fever, chills, sore throat, swollen glands, body aches, and fatigue.
Epstein-Barr virus (EBV), which can cause mononucleosis (mono).
Varicella-zoster virus, which can cause chickenpox and shingles.
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Additional authors on the study include Nicola P. Klein, MD, PhD, Bruce Fireman, MA, Paula Ray, MPH, and Edwin Lewis, MPH, with the Kaiser Permanente Vaccine Study Center; Nandini Bakshi, MD, with The Permanente Medical Group; and Claudia Vellozzi, MD, MPH, with the Immunization Safety Office, Centers for Disease Control and Prevention.
About the Kaiser Permanente Vaccine Study Center
Founded in 1985, the Kaiser Permanente Vaccine Study Center began as a way of responding to numerous requests to use Kaiser Permanente’s large population for vaccine efficacy studies. Key studies have focused on Haemophilus influenza, type B (Hib), chickenpox, pneumococcus, rotavirus and flu vaccines. The center operates 31 sites in Northern California and collaborates with Kaiser Permanente’s Northwest, Hawaii and Colorado regions, as well as participates in several Centers for Disease Control and Prevention and National Institutes of Health studies.
Symptoms
Symptoms of Guillain-Barre can get worse very quickly. It may take only a few hours to reach the most severe symptoms, but weakness that increases over several days is also common.
Muscle weakness or the loss of muscle function (paralysis) affects both sides of the body. In most cases, the muscle weakness starts in the legs and then spreads to the arms. This is called ascending paralysis.
Patients may notice tingling, foot or hand pain, and clumsiness. If the inflammation affects the nerves to the diaphragm and chest and there is weakness in those muscles, the person may need breathing assistance.
Typical symptoms include:
Loss of reflexes in the arms and legs
Low blood pressure or poor blood pressure control
Muscle weakness or loss of muscle function (paralysis)
In mild cases, there may be weakness instead of paralysis
May begin in the arms and legs at the same time
May get worse over 24 to 72 hours
May occur in the nerves of the head only
May start in the arms and move downward
May start in the feet and legs and move up to the arms and head
Numbness
Sensation changes, including pain and tingling
Tenderness or muscle pain (may be a cramp-like pain)
Uncoordinated movement (cannot walk without help)
Other symptoms may include:
Blurred vision and double vision
Clumsiness and falling
Difficulty moving face muscles
Muscle contractions
Palpitations (sensation of feeling the heart beat)
Emergency symptoms (seek immediate medical help):
Breathing temporarily stops
Can’t take a deep breath
Difficulty breathing
Difficulty swallowing
Drooling
Fainting
Feeling light-headed when standing
About the Kaiser Permanente Division of Research
The Kaiser Permanente Division of Research conducts, publishes and disseminates epidemiologic and health services research to improve the health and medical care of Kaiser Permanente members and the society at large. It seeks to understand the determinants of illness and well-being and to improve the quality and cost-effectiveness of health care. Currently, DOR’s 600-plus staff is working on more than 250 epidemiological and health services research projects.
About Kaiser Permanente
Kaiser Permanente is committed to helping shape the future of health care. We are recognized as one of America’s leading health care providers and not-for-profit health plans. Founded in 1945, our mission is to provide high-quality, affordable health care services and to improve the health of our members and the communities we serve. We currently serve more than 9 million members in nine states and the District of Columbia. Care for members and patients is focused on their total health and guided by their personal physicians, specialists and team of caregivers. Our expert and caring medical teams are empowered and supported by industry-leading technology advances and tools for health promotion, disease prevention, state-of-the-art care delivery and world-class chronic disease management. Kaiser Permanente is dedicated to care innovations, clinical research, health education and the support of community health.