As with other vaccines, COVID-19 vaccines can cause local and/or general side effects. However, not everyone that is vaccinated experience side effects. Side effects that may occur are a mild fever, chills, fatigue, nausea, headache or a reaction at the injection site such as redness, pain, stiffness or swelling. These symptoms disappear spontaneously after a few hours to a few days after vaccination and can be relieved by taking a painkiller or a fever reducing drug. In (very) rare cases, a serious side effect (such as an allergic reaction) may occur.