Nearly all medications involve risks to the patient, and vaccines are no different. But the risk of injury due to a vaccine is relatively minor, especially when compared to contracting one of the diseases they are designed to prevent. Even rarer are those circumstance when a person suffers a serious and life-debilitating injury from a vaccine. Such injuries do happen, however, and below are some of the more common serious syndromes. All of them involve inflammation resulting from an auto-immune overreaction to the vaccine.
Shoulder Injury (or SIRVA for Shoulder Injury Related to Vaccine Administration)
When a vaccine is administered in the upper part of the arm, injury to the shoulder and rotator cuff can occur. Some people may experience mechanical injury from the injection itself, especially if the needle enters the bursa. Others may experience injury due to inflammation due to the vaccine itself. These injuries can be quite debilitating and can lead to severe pain, restricted range of motion, and even paralysis of the arm. Adhesive capsulitis and brachial neuritis have been known to result from vaccine administration.
Anaphylaxis or Anaphylactic Shock
Sometimes the immune system overreacts to a vaccine, which can cause inflammation throughout the body. This can be manifested by itching, hives, and swelling of the throat and lowering of blood pressure. In the worst cases, a person can even go into anaphylactic shock, where the body’s organs begin to shut down from lack of blood perfusion due to low blood pressure.
Encephalitis
Like anaphylaxis, encephalitis is an auto-immune reaction that causes inflammation. But encephalitis refers specifically to inflammation in the brain. Encephalitis can manifest with headache, fever, and fatigue.
Guillain-Barré Syndrome
Also an auto-immune disorder, GBS refers to the immune system turning on the body’s nerves. The immune system attacks the nerve cells and damages them, which can lead to weakness and paralysis.
Transverse Myelitis
Myelitis is inflammation to the myelin sheath that coats our nerves and contributes to the conduction of electrical signals through them. Again, the immune system sometimes overreacts to a vaccine and turns on itself, attacking the body’s myelin in the mistaken belief it is a foreign invader. Destruction of myelin can damage our motor and sensory nerves in the spinal cord and throughout the body, resulting in a variety of symptoms that can include weakness, paralysis, blurred vision, and incontinence.