Colorado Doctor Lists Bizarre COVID Vaccine Side Effects As more and more people get vaccinated for COVID-19, doctors are learning more and more about the body's response to it, including bizarre side effects. A Colorado Medical Editor for CBS4, Dr. Dave Hnida does a weekly question and answer broadcast for the Denver TV station, where he outlined some of the normal, and more abnormal side effects his patients have reported to him. Get our free mobile app He attributes the side effects to the body's immune system's response to the vaccine, which can vary greatly from person to person. While most experience side effects such as aches, pains, and fatigue, Hnida also talked about some more uncommon and strange side effects, such as what's known as 'COVID arm:'