Close to one in five (19%) people in the survey shared that they are scared of the short-term side-effects of the booster dose. These temporary symptoms are similar to those you might notice when you get a flu shot, such as a sore arm, fever, body aches, headaches and tiredness for a day or two. While it is natural to fear these symptoms, they do not mean that you are sick. Rather, it is a signal that your immune system is responding to the booster shot and building up protection against COVID-19.