Summary about Disease
Yellow fever vaccine-associated neurological disease (YEL-AND) is a rare but serious adverse event following vaccination with the yellow fever vaccine. It encompasses a spectrum of neurological complications, including encephalitis (inflammation of the brain), acute disseminated encephalomyelitis (ADEM), and Guillain-Barré syndrome (GBS).
Symptoms
Symptoms vary depending on the specific neurological complication but can include:
Encephalitis: Fever, headache, altered mental status (confusion, disorientation), seizures, weakness, paralysis.
ADEM: Sudden onset of neurological symptoms including vision loss, weakness, difficulty coordinating movements, seizures, and altered mental status.
Guillain-Barré Syndrome (GBS): Progressive muscle weakness, often starting in the legs and ascending upwards; tingling or numbness in the extremities; difficulty with breathing.
Causes
YEL-AND is caused by the yellow fever vaccine itself. The exact mechanism is not fully understood, but it is believed to be related to the attenuated (weakened) live virus in the vaccine triggering an abnormal immune response that attacks the nervous system.
Medicine Used
4. Medicine used Treatment for YEL-AND focuses on managing the specific neurological complications and supporting the patient's recovery.
Encephalitis: Antiviral medications (if a viral cause other than the vaccine is suspected), anti-seizure medications, corticosteroids to reduce inflammation, supportive care (e.g., mechanical ventilation if needed).
ADEM: Corticosteroids, intravenous immunoglobulin (IVIG), plasma exchange (plasmapheresis), supportive care.
Guillain-Barré Syndrome (GBS): Intravenous immunoglobulin (IVIG) or plasma exchange (plasmapheresis), supportive care (e.g., mechanical ventilation if needed), pain management.
Is Communicable
No, YEL-AND is not communicable. It is a reaction to the vaccine, not an infectious disease.
Precautions
Precautions to minimize the risk of YEL-AND primarily involve careful assessment of individuals before vaccination to identify contraindications and risk factors. These include:
Age: Infants younger than 6 months, and adults over 60, are at increased risk.
Immune status: Individuals with weakened immune systems (e.g., due to HIV/AIDS, cancer treatment) should not receive the vaccine.
History of thymus disorders: Individuals with a history of thymus disorders are at increased risk.
Prior reactions: Individuals who have had a severe allergic reaction to the vaccine or its components should not receive it again.
Pregnancy/Breastfeeding: In general, yellow fever vaccination should be avoided during pregnancy and breastfeeding unless the risk of exposure to yellow fever outweighs the risk of vaccination.
How long does an outbreak last?
YEL-AND is not an outbreak. It is a rare adverse event following vaccination.
How is it diagnosed?
Diagnosis of YEL-AND involves:
Clinical evaluation: Assessment of the patient's symptoms, neurological examination, and medical history (including recent yellow fever vaccination).
Neuroimaging: MRI of the brain and spinal cord to look for inflammation or other abnormalities.
Lumbar puncture (spinal tap): Analysis of cerebrospinal fluid (CSF) to look for signs of inflammation or infection.
Electrodiagnostic studies: Nerve conduction studies and electromyography (EMG) to assess nerve and muscle function, particularly in suspected cases of GBS.
Ruling out other causes: Testing to exclude other possible causes of neurological symptoms, such as infections, autoimmune diseases, and structural brain lesions.
Timeline of Symptoms
9. Timeline of symptoms Symptoms of YEL-AND typically appear within 2-30 days after yellow fever vaccination, although onset may vary.
Important Considerations
YEL-AND is very rare. The benefits of yellow fever vaccination generally outweigh the risks, especially for individuals traveling to or living in areas where yellow fever is endemic.
Prompt diagnosis and treatment are crucial for improving outcomes.
Healthcare providers should be aware of the potential for YEL-AND and report suspected cases to public health authorities.
Patients should be fully informed about the risks and benefits of yellow fever vaccination before receiving the vaccine.