Active rotavirus immunization is carried through as an oral vaccination from the age of 6 weeks. At intervals of at least 4 weeks, there can either be used a monovalent vaccine which has to be given twice or a vaccine containing 5 different serotypes which has to be applicated thrice. At the age of 24 weeks, immunization has to be finished as the risk of intestinal intussusception (invagination) increases with a later onset of vaccination. Rotavirus vaccine is tolerated well, the protection rate is about 85 %. Possible side effects are a lack of appetite, diarrhea, fever and irritability. Contraindications for the rotavirus vaccine are immunodeficiency, acute illness with fever and a known severe allergic reaction to components of the vaccine.