Incidences of Acute Demyelinating Encephalomyelitis (ADEM) Following Vaccinations

Acute disseminated encephalomyelitis (ADEM) is a rare autoimmune disease marked by widespread attack of inflammation in the brain and spinal cord. ADEM typically damages myelin, causing destruction of white matter. It is often triggered following a viral infection or vaccination. ADEM's symptoms are similar to multiple sclerosis (MS) and is considered part of the multiple sclerosis borderline diseases.

In an article published in the Journal of Clinical Neuroscience titled “Post-vaccination encephalomyelitis: Literature review and illustrative case,” the authors studied reviewed data of incidences of encephalomyelitis following vaccination.

The researchers studied various categories of acute disseminated encephalomyelitis (ADEM) such as transverse myelitis, neuromyelitis, and multiple sclerosis.  The study found that 75% of encephalomyelitis cases occurred following vaccination or infection.  ADEM has been linked to several vaccines including rabies, smallpox, measles-mumps-rubella (MMR), influenzaand hepatitis B.

ADEM is seen in about.4 per 100,000 people that are vaccinated.  However, ADEM following immunization seems to occur significantly more frequently following primary vaccination as opposed to revaccination (booster vaccines).  In other words, for childhood vaccines such as DTAP and MMR, it is more likely to result in ADEM during the initial vaccination than later in life when boosters are administered.

Patients with ADEM usually first present with fever followed by progressive neurological symptoms such as numbness and tingling of the extremities and urinary incontinence.  If you or your child experiences fever 2-42 days after vaccination, seek medical attention immediately as it may be a serious condition.