expected after certain vaccines. These findings were consistent with safety signals that many regulatory agencies had already recognized and incorporated into vaccine guidance.

Rare Side Effects Identified

Researchers and health agencies have reported rare but recognized side effects associated with some COVID-19 vaccines.

These include:

Myocarditis

Inflammation of the heart muscle, seen most often in younger males after mRNA vaccines. Most reported cases were mild and patients recovered with appropriate medical care.

Pericarditis

Inflammation of the lining surrounding the heart. Like myocarditis, many cases responded well to treatment.

Guillain-Barré Syndrome (GBS)

An uncommon neurological disorder that has been observed after some vaccines, particularly adenoviral-vector vaccines such as AstraZeneca and Johnson & Johnson, although the overall risk remains very low.

Cerebral Venous Sinus Thrombosis (CVST)

A rare type of blood clot in veins draining the brain that was linked to AstraZeneca vaccination in a very small number of individuals, particularly during