If you’ve recently been vaccinated, your immune system is working hard and learning how to fight SaRS-CoV-2 spike proteins. This will mean that if you ever encounter the real virus, your body is ready! . But along the way, sometimes our bodies react in weird ways to the COVID-19 vaccines. A sore arm, achiness, mild headaches, or even swollen armpit glands are all normal. Most side-effects go away within a few days. Swipe through to see how common they are. . There are extremely rare side effects, particularly linked to the AstraZeneca vaccine, that can be more serious. Our friend @science.sam has a great story highlight about the signs of the severe clotting side effect called VITT. . The stats in this post are from a big UK study of reactions to the Pfizer/BioNTech and Astrazeneca vaccines, published in April 2021 in the Lancet. You can read it here: tinyurl.com/SUFSideEffects