What should I do if I develop serious side effects? What should I do if I feel ill after having a COVID-19 vaccination?

Side effects such as a slight fever, chills, tiredness, nausea, headache or a reaction at the injection site such as redness, pain, stiffness or swelling are normal and should pass spontaneously. These symptoms disappear after a few hours to a day following vaccination and can be relieved by taking a painkiller or a fever reducing drug. In (very) rare cases, a serious side effect may occur. In case of more serious side effects, such as high fever, side effects that last longer than two days, low blood pressure, shortness of breath or severe allergic reactions, you should contact your general practitioner or family doctor.

Another potentially very rare side effect may be the development of a blood clot1 up to 14 days after vaccination with a COVID-19 vaccine, especially in younger people. If you experience any of the symptoms below, you should seek medical help immediately. After all, a quick response can help with recovery and can prevent further complications.


  • shortness of breath
  • Pain in the chest or stomach
  • swelling and/or coldness of an arm or leg
  • severe or worsening headache or blurred vision after vaccination
  • persistent bleeding
  • several small bruises, red or purplish spots, or blood blisters under the skin

If anyone does experience side effects after vaccination that are not mentioned in the leaflet, they can report those side-effects to the Poison Centre, which is responsible for registering all types of adverse reactions to medicines and vaccines, or directly to the FAMHP (Federal Agency for Medicines and Health Products) via this link.

1Combination of a reduced platelet count with severe thrombosis