From FDA

Possible adverse reactions shown in the FDA’s “working list” include:

Guillain-Barré syndrome
Acute disseminated encephaloymelitis (“Characterized by a brief but widespread attack of inflammation in the brain and spinal cord that damages myelin – the protective covering of nerve fibers,” according to NIH.)
Transverse myelitis
Encephalitis/ myelitis/ encephalomyelitis/ meningoencephalitis/ meningitis/ encepholaphathy
Convulsions/seizures
Stroke
Narcolepsy and cataplexy
Anaphlyaxis
Acute myocardial infarction
Myocarditis/pericarditis
Autoimmune disease
Deaths
Pregnancy and birth outcomes
Other acute demyelinating diseases
Non-anaphylactic allergic reactions
Thrombocytopenia
Disseminated intravascular coagulation
Venous thromboembolism
Arthritis and arthralgia/joint pain
Kawasaki disease
Vaccine enhanced disease